At 5:34, I immediately realized what the problem was. The spurving bearings were not in line with the panametric fan, therefore the hydrocoptic marzlevanes were not engaging with the pandermic semi-boloid slots in the stator correctly. That easily explains why it was falling out of gear.
For American V belts, the letter in say, a B38 belt denotes its cross section size. The following number denotes the outer circumference, minus two inches in length. That would make a B38 belt 36 inches outer circumference. An X suffix denotes that it is a clogged style belt
Thanks a lot. I couldn't get imperial B (21/32") belts here, so I ordered the closest metric (17mm) size. The DoAll spec on the data plate links to a V5L420 modern spec on their spares website. 42" converts to 1092mm, so i choose the closest standard whch was 1060mm. I since realised that this saw now has a none standard motor mount, so maybe they needed a shorter belt to compensate. I have been informed tha tthe cogged style is wrong for this use case, so I will need to get a different one. Once it is all back together, I will try out the old 965mm and the new 1060mm belts and see which is better, then order a new uncogged belt of that length.
PTFE shoe that fits over the fork to make up the gap bergen the fork and groove in the dog. Oilyte "buttons" instead of the ball bearings. Either way you'll need some kind of positive latch/locking mechanism to keep the fork in place if there is no back rake on the dog teeth. Just have to make sure it's not putting pressure on the fork to keep it in place.
Sadly, I can't offer any useful input for you I but do want to say that I enjoyed your video, so thanks for posting. The comments look interesting so hopefully you'll get some good info from more knowledgeable viewers. Looking forward to the fix. - Heather
Looking at the wear pattern on the shift fork ( heavy near the shift rod, lighter near the contact points ) suggests to me that the fork is bent or misaligned and therefore may not be pulling the dog clutch fully into mesh or holding it in mesh. I was also thinking that those contact balls may be designed to be free to spin but the balls and their sockets have worn "beyond the wear limit", another possible cause of only partial engagement of the drive.
Good observation Gary. I uspect you are right, I'll check it with a square tonight. You are ceratinly right about the ball retention pockets being worn beyond limits as well. I drew up a replacement yoke yesterday.
Things I'd be considering that might (or might not) help: 1. The balls on the yoke look non-round from wear, so maybe too small 2. The nylon bushing on the faceplate side of the shift lever has a ton of slop 3. The reverse slope on the high speed drive dogs
1. Yep. I measured them yesterday. 6.15mm balls, 6.75mm slot. Plus some flat spots on the balls. 2. Yep, I dont thing that plastic bush is original, it is probably already a repair for a slogged out hole in the sheet metal frame. 3. Yep, that one is on me :) I drew up a replacement yoke in CAD yesterday.
I'm concerned about the slope on the back of the drive dogs. Seems like the moment you stop applying torque (like when you stop cutting) it's possible the blade/wheels momentum will briefly back-drive the gearbox, causing the ramps on the rear of the drive dogs to push the selector vac to the middle.
G’Day Mark, I read the 130 comments so far, and concluded I have nothing new to add/suggest…however it’s rewarding to see that you’re tackling this thing. I’m sure you’ll get it sorted! 👍
Drive dogs on motorcycle gearboxes definitely have back rake to keep the gearbox in gear. That applies to both the drive side and the engine braking side of each drive dog. But those things have a lot of vibrations and sudden load shifts. I wouldn't think that raking the drive dogs could create a problem but you do need to set them spot on to the proper compound angle for grinding to ensure you'll get full face contact on all of them instead of point contact
As I now better understand that the shifter needs to positively hold them engaged, I think it would be better with my dodgy set up to grind vertical to keep it simple, and avoid radius at the root with clearance.
This exact issue happens on the bikes I race. They bend the selector forks slightly due to mis-shifting (forks having no where to go) then they take out the nice edges of the dogs as they don't select properly. New forks that fit well into the slots fix it (they have little wear pads on the good ones, never seen balls I guess this is because they are hard)
Between the slop in the fork, and the parent point contact on the dog faces, there looks like there's plenty of opportunity for the dogs to work loose under varying load conditions. Also, I think the relief that had been cut originally is important to keep the engagement fully seated. Any debris, or even hydraulic action of the oil may initiate the dogs decoupling at low load.
You have so much patience. I’d love to see a graph of your decision tree. Nothing makes it to the scrap pile. But there has to be a cutoff somewhere. Maybe there’s more old machines here in the US. I’d never consider this kind of work. Cool as it is. I just spent $1k on parts to fix a Mazak 200M that’s 20 years old. And I won’t do a fraction of the work you’ve done on this one old band saw. Very cool work. Thanks for all the videos.
Hi Craig, I guess, being a hobby, and DoAll pricing it's parts in EWD (Equivelent weight in Diamonds), I would rather make parts at irrational cost in time, than buy them :) www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
I gave myself the same puller. The quality leaves a lot to be desired, but I've often been glad to have it. Highly recommended for occasional use! For next Christmas I can recommend one of these inexpensive inner bearing pullers! You don't need it very often, but when you do, it saves the day! 😉
I just so happen to be working on the same model bandsaw gearbox. If I can supply any photos of my parts, please let me know. Mine appears to be in much better shape then yours.
Hi Steven. Thanks. I appreciate that. Does yours also have the balls in the shifter fork? Looks like other DoAll models have (hardened?) steel weat plates there. www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork Does yours have detents in the change linkage? ruclips.net/video/1t6aH7WTzC8/видео.html
@@RotarySMP Hi RotarySMP. Yes, mine has balls in the shifter fork, but looks a little different than yours. No, mine does not have detents. Also, no wear plates. I believe that the gear shift lever should be either at a 90 degree left or right position when fully engaged. This "locks" the shift lever in position. Your gear change lever appears to be a DIY repair. Maybe the shifter fork is as well.
On another note, I'm going to change out the output shaft bearing to a double row if I can, for better alignment and rigidity. Think I will also change out the bushing for a needle bearing and inner race. This is how the later gearboxes are constructed. Evidently, DoALL knew this was a problem in the design and improved it.
@@steventimme5268 Yep, that gear change lever was missing when I got my saw, so I made it. It has no detents. I also remade the cam and the cam slot. Once I have the play out of the system, I will ave to see whether it latches in the two engaged position, or needs a detent added. I drew up a new shifter fork yesterday, and will go for a wear plate design.
@@steventimme5268 Yeah, I would have put in a needle roller if I had thought it through. By the time I realised, Luke was already making the shaft with the pinion to the original design. Given how little work my saw will see, I expect the intershaft bushing to easily outlive me.
I'm a retired certified millwright (64). I also used to race sports cars (relevant later). In my opinion those dog rings need to have rake on them to stay engaged. You stated that you wanted to make them flat. I disagree. You noticed that the low speed dogs had rake. It would make sense that the other dogs also have rake --- no ???? Like I stated above, I used to race sports cars. The car I owned was a Lola T-360 formula car converted to a full body A sports racer. The relevant point to your video is that this race car had a FT200 gearbox (very expensive to repair and maintain). This gearbox has straight cut gears with dog rings. It was very common to lose a gear in a race, the thing would jump out of gear as soon as you let of the gas coming into a high speed corner just before I had to dive on the brakes. What happens is that the rake on the dog ring and the gear would get smashed because of the violent shifting. The rake on these parts was 7 degrees. Even though there was still some "slight" angle on the parts it would not hold because the sharp tip got knocked off and that's all it needed to lose to not hold. I believe you have the same issue. You are also correct, in my opinion, to repair the shift fork and those ball bearing ends. You wouldn't want metal on metal contact and the ball bearing would act as the rollers. Just my opinions. I may be wrong.
Thanks for the feedback on that. The reason I picked up on 0 rack, was that another DoAll owner reported that is how the dogs are in his gearbox. This is only a 1.1kW drive, and gearchange is only stationary. I will remake the shifter without balls, as later DoAll gearboxs also dropped that design for sliding slippers.
Making a new shift fork is a worthwhile job. Do that for sure. As well as correct the faces on the drive dogs. I'm not as sure about the linkage, but your thoughts are sound. Perhaps add a spring detent setup to hold the linkage in position.
Belt classification Z=10mm A=12.7mm (13mm) B=17 m B38 means B (17mm wide) x 38" (38 x 25,4=965mm) And letters in the end... Li = lenght inside La= langht outside Lp = Ld = lenght middle That means that you need the belt 17x965 Li Ask any belt suplyer like OPTIBELT in Austria
Thanks for that. I am not sure if that 965mm belt which came out was the right length though. The old DoAll spec D9-3770 listed on the dataplate comes up on their website as... www.doallsaws.com/9770-v-belt ...BELT V 5L420 The 42 inches converts to 1092mm, which Is why I ordered the 1060mm as nearest standard length. I have been informed that I should not use an X (knotched back) belt in this application, so I guess I need another belt.
I'd certainly try to get the 3 engagement surfaces squared up to ensure better contact between the selector and the gear. This would reduce any force trying to disengage the gear. Of course, all that slop in the selection mechanisms is too much and needs to be eliminated too.
My opinion is that the drive dogs once engaged, should naturally "want" to stay engaged. So, from your list, I would do #3 first and then tighten up the other issues. :)
That is good logic, but the low gear dogs already have good mesh and back rack, an they were the ones jumping out of gear constantly. I think a saw has enough vibration that you need the shifter to hold the selector in engagement.
I think it’s the yoke given only the ball bearings should be in contact - no wear in the sides which you have. Making a gearbox sleeve to self hold the gear lever seems wise to take out the yoke lean.
The gearbox was previously run until the intershaft bushing was so completely slogged out that a Woodruf key was released. I suspect that wear on the side of the shifter fork was from when the bushing was deflecting. But year, it is a crap design with the balls an completely worn out, so I will replace it.
I was about to comment at the start of the video that a hacksaw looks faster, then you say the worn out bandsaw is just faster than a hacksaw. Hopefully the repair improves reliability.
In a manual transmission car, there are spring loaded ball bearings that seat into detents on the shift arms. Those play a big part in keeping the car in gear. If you add something like that to your shift arm it could help keep it in place. Maybe some kind of friction lock could also work or just a really heave lever flipped so gravity helps keep it in place. It is possible all of the loose components combine with vibration is what is popping it out of gear.
The main problem, as far as I can tell from your footage, is de shifter fork. Judging by the difference in positioning in the fork, the balls have been added later. I would fabricate a new fork, with minimal play, without balls. I have never seen balls on shifter forks in any gearbox. If the play between the drive dog wheel and the fork is minimal, and the change lever is fixed, the gears will stay in place.
The balls do reduce shifting friction and wear. If the original fork wore down so much that it needed fixing like that, then it is definitely a wear zone. But wear is most likely from incorrect alignment, so there is that...
Years ago,an author I admire came up with the term. 'Intelligent lethargy'. As in,sometimes problems solve themselves. With people problems, surprisingly often. With things mechanical, less so. A noisy bearing can after all be solved by replacing the entire transmission. But only if you have a spare transmission. And so forth. Good luck with this. @RotarySMP
It looks like someone before was chasing the same issue and put a ton of rake on the selector. This seems like a patch on another issue, the selector fork shouldn't have much play at all. I agree with the other comment that disengagement may be because of brief backdriving when you take a load off. Also, the rounded shoulder on the side you reground is a no-no. I would aim for a very slight back rake, maybe 5⁰, to make them hook together. Not to keep them engaged, but enough to pull then together should they meet in a slightly off-engagement position. You wouldn't want the selector fork to be under constant load while cutting, it should just keep the parts in a place where they won't be able to disengage - otherwise it will wear out rapidly.
Thanks for you inputs. You are right. When I first did the gearbox repair, I incorrectly thought the shifter was only for gear changing, but now see it is important for retaining the gears engaged. That oldshifter is toast. I drew up a replacement yesterday.
I didn't watch the the older video on this, but has this shifting mechanism a sort of end-position-arrester.. like a over center latch or a spring loaded ball + groove? Is there anything in this whole setup that keeps the drive-dog in its Hi/Lo gear position respectively? Maybe that feat was caused by the loose fit of the lever in the past? A sort of over-center thing.. but stuff wears out over time. What I mean is - if u put in a bushing and make it too rigid it might not work as intended?
Sort of. The slot which the excenter rides in nips up at both ends of rotation.However, that was not enough to stop it falling out of gear (due to the shifter fork wear).
What is holding the drive dogs engaged while the machine vibrates during the cut? It seems to me either you need a back rake to pull them towards each other or you need some kind of spring in there.
I think that it is supposed to be that shifter fork, but it is all so slogged out, that it fails to retain the shifter in position. I drew up a replacement fork yesterday.
With all the space around the drive fork it seems like there is a thrust bearing/washer that is missing. Maybe the previous owner lost it and tried to take up the space by staking the balls in? Also, I have a hunch that the bracket that holds the selector arm is not stock, and that is contributing to the excessive play.
Good points. I hav no idea what the original tolerances were, but these are 6.15mm balls, in a 6.75mm slot (seems excessive), but the balls are so poorly retained now, that they play is a couple of mm. The yoke looks a bit bent, and also has a 1/2mm of wear. I drew up a replacement Yoke yesterday. I think that bracket is probably original. DoAll had some pretty agricultural design practices. :)
Recutting the shoulders seems to be more like something to do with a nice and sharp endmill than a grinding disc. And indeed, the fork needs some attention too.
@@RotarySMPthat wouldn't be too much of a problem for a carbide end mill though, but on reflection grinding is the way to go although I'd go diamond grinding blade myself.
There are other opinions that vertical dog faces also work (I will still need to grind the high speed side). No there is no detent system. I will probably add one.
Well, that`s the issue, the gearbox should not be driving your nuts - but the bandsaw blades... You just gotta figure out how to decouple it from your nuts and onto the saw-drums... Quite the simple solution... Edit- Also, i would leave the back-rake on the dogs... That seems to be extremely sensible and useful... Pure 90deg makes sense, as it should never jump out by itself, but a biting rake wants to pull the two together - which is better if there is any wear... Cheers; Best regards! Steuss
Thanks Steuss. You are right there. I wont regrind the nice flanks with back rack on the low speed dogs, but will regind the high speed dogs, to give nice flat and vertical faces.
That shifter fork is toast and wore out beyond repair. Make a new one and new balls. Think the balls maybe wrong size as well. **I just read other comments , like other guy said balls may not be original equipment. Also believe the opening in fork is wore way to big. Believe it should be symmetrical
Gears when driving through dogs should always pull together. If a selector is holding the gears together with its drive it wears out very rapidly. There need to be equally spaced radial positions for the dogs. so it locks into any position during rotation. At worst the drive faces on the dogs should be 90 deg but that is if the gear is being pulled together with its lead. For the sort of load it is taking you could easily hold it in position with a bronze selector fork and a external gate on the selector. It really depends on what sort of loads you intend to use. As for the wheels you usally have a radised contact face with its crest in the center, drive and idler.
I've never seen a shift fork with steel balls in the tips before, that looks very much like a badly executed DIY bodge to me. Note how one hole is very close to breaking out of the edge of the fork. Steel shift forks would typically have a pad of bearing material (e.g. bronze) on the ends. The damage to the ball's surface with numerous small flats show they aren't spinning within the fork, and instead will be scoring the shift hub.
I have feedback form other DoAll owners that this is an original DoAll bodge. I agree it is a crap design, and other DoAll models didn't use it. www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork I drew up a replacement fork yesterday. I am unsure whether it is better to make a case hardened part, of braze on bronze slippers.
I just rebuilt my DoAll. I found that I needed to reduce the spacing between the low range and high range dogs. I did that by inserting a shim on the output shaft between the bearing and gear. Also your shifter fork might not have the correct ball size... i didn't measure my fork but yours seems to have too much slop inside the dog selector slot. Good luck.
I think I would square the drive dogs up. I would get rid of the ball bearings on the shift fork ends in favor of Bronze brazing the sides of the fork and re-machining it for a running fit in the groove. And finally remove as much slack as possible from the rest of the linkage. The B38 in the old belt is all you need to match for the length.width. The X in the new belt part number denotes a notched back belt. I once bought a cutoff band saw cheap because it made a lot of rumbling noises while running. The previous owner had replaced the belt with a notched back belt and as the belt wore, the notched sections turned into little bumps making the rumbling noise. Replacing the belt with a smooth backed belt solved it.
Thanks for your excellent inputs. I'll be more carefull this time to get a nice flat grind on the dogs. You are right, those balls are a crap design. Even if correct, the peened retention makes for point loads which would wear out fast. Do All used hardened blocks on some saws... www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork .. so I drew up a replacement fork yesterday. Undecided whether to go for a hardened steel fork or bronze wear surface. DoAll also added detents on the linkage of some saws... ruclips.net/video/1t6aH7WTzC8/видео.html ...so I will add some to mine as well. Thanks for the belt knowledge. I didn't know that, and got the wrong belt. I'll get another one.
I don't like all that slip in the shifter fork. I would like to see a better detent for the shifter as well. I was not able to find Homer on Ios but I did find allot of fun trails that lead to beaches there and enjoyed the ATV driving there.
Hi Robert, Yeah that shifter fork is toast. I had incorrectly concluded it was just for shifting when I first did the box, but now understand it is what holds the gear engaged. I drew up a replacement ysterday.
I don't see how those balls could be expected to work, so I find myself in the "not original" camp. They don't have anything to push against in the fork (other than a bit of scruffy peining) Balls in each side into blind holes (offset from each other) might work. But maybe look at brass-facing the fork with TIG brazing and machining to be a nice running fit. I am somewhat surprised that there seems to be no sign of any sort of detente. Maybe the ball handle is a replacement and the original one was heavier?
Hi Andy, given your motorbike experience, I was hoping your would give me your feedback. Thanks. I have feedback from other DoAll owners that it is original, but agree it is a crap design. Even if done "well", the staking around the balls leads to point loads which will wear fast. The balls are only 6.15mm in a 6.75mm slot, so there would be a far bit of play even if the balls were more constrained. DoAll used what looks like hardened slippers on some other saws... www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork That existing fork is toast, so I drew up a replacement yesterday. I am at two minds whether to go with soft bronze slippers, or hardened steel, as it is well lubricated. DoAll also used detents on some other models of saw... ruclips.net/video/1t6aH7WTzC8/видео.html ...so I will add some. The ball handle and sifter rod is a replacement, as I made it :) The original was missing when I got the saw, and would have been just a rod with a 90 bend in it. I am pretty sure the plastic bushing in the frame is also a previsous mod, as the original rod likely slogged out the frame hole.
Certainly not an expert, but I think I agree with you that it's both the brackets and the selector fork. If the balls are meant to be the bearing surface between the fork and the dog gear groove, then there's a ton of wear on all the other surfaces that shouldn't be making contact. The balls also look like they're showing a lot of wear. I'd expect the bracket play isn't maintaining thee axial clearance for the fork, while the worn balls are allowing excessive side to side movement. I'd guess the fork is twisting and binding under load because it has the room to do so, and that's what's letting the dogs disengage. New fork with oversized balls to fit the worn slot, and fix the brackets to hold it in place.
Good inputs. That shifet fork is toast, and I will make a replacement. DoAll used the balls on some saws, but hardened blocks on others. I drew up a replacement fork and will make that, and then address the play in the linkage as well.
The selector balls look like they've been replaced and should be a larger diameter so the selector fork has less play. The current amount of play looks enough for the dog to slide out. Regarding the band jumping out, can you tilt the driven wheel back so the band will tend to stay on, instead of walking its way off.
I wonder if the selector balls were even a Do-All feature, or added by one of the previous owners? There is no adjustment on the driven wheel, except by shimming the gearbox. I'll look at doing that when I reinstall it.
@@RotarySMP If the balls were OE by the looks doall would have put a bit more meat around them, in any event the 'oles they are in a egged out. Make a new selector fork that fits the shift groove better and arrange some positive locking in each gear if you can too. The dog clutches should be square or ever so slightly undercut, undercutting used to be a common racing mod for motorcycle gearboxen to improve gear locking although it does make the dogs reluctant to shift out of gear, not that you are making clutchless down changes on a bandsaw though. 😀
@@julias-shed I just found a picture of the original shifter fork. Obviously made of Platinum! www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork Looks like I need to make a new shifter fork, with hardened blocks.
The shifter fork is the culprit alright, I think. Those balls had flat spots by the look and were very sloppy fit in the slot and the fork, easily enough play for it to disengage under load. They have likely been replaced judging by the staking and may be undersize from the original. I'd go for some replacements a size (or two) up that are a close fit in the slot. How much side play is there in the shift fork shaft? The scoring on the fork says quite a lot, it runs in another bushing? ovaled out? In other words, all the thoughts you had ;) You could even consider adding a third ball in the scored area of the fork to maintain planarity with the slot. That staked ball is a weak point in the design, the staking contact points with the balls are just a thin lip of steel. If you can't get it tight and robust, i'd be tempted to ditch the balls and braze on a couple of bronze slipper pads instead with a good surface area. E.G. like a motorcycles' shifter fork. A detent mechanism somewhere for engaged/disengaged would also be very useful.
Thanks for your design review. Very helpful. The shifter shaft has a nice sliding fit. It is not worn out. But since the balls are not restrained, there is a couple of mm of sideways play. The balls are 6.15mm and have flat spots, while the slot is 6.75mm. I don't have any replacment balls in a better size, and agree that it is not a very robust design anyway. DoAll used shifters with hardended blocks instead of balls on some models, so yesterday I drew up a replacment fork like that. As it is a well lubricated location, I am at two minds whether to use hardened slippers or bronze.
@@RotarySMP Right, so the scoring is a result of the ball hitting the limit of the slot face but the fork continuing to move due to the play between ball and fork. Yes I think the pads are the way to go, either type would work well I'd say given they are constantly bathed, 6 of one 1/2 dozen of the other.
@@m3chanist I was thinking some more about it, and think that bad surface wear on the shifter fork cauld also have been caused back when the intershaft bearing was so slogged out that the output shaft (carrying the selector ) was misaligned. Since my heat treatment oven is dead, I guess brazing on bronze wear pads is more realistic at this point.
@RotarySMP Sounds like a plan. 👍 I envy your doall and it's gearbox, I have a wood saw that I converted with a 1kw DC motor and speed control I repurposed from old rock tumbler, it work OK but I suspect you have much more low speed torque.
I was looking at the selector yoke and was noticing that the cutout in the center doesn’t match the wear marks i’m seeing above it. Is there a chance that it was a home made piece to replace the original?
It is welded to the shifter shaft. The replacements from DoAll appear to be bolted, so it is most likely shop made. www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork Other owners have reported that the design with balls is a DoAll design, but it seems like crap.
I would put significant undercut on all the drive dogs, like an angle of 10 to 15 degrees. There is really no reason not to, because you never need to shift it OUT of gear when using a high load. I would replace the 2 balls because they are visibly trashed, AND leave them able to rotate which should help to reduce flat spots and overall wear. I suppose they need to be peened so they just rotate freely, but still have some ball hanging out each side. You might need to go up in ball size to allow for wear in the shifter groove. Then fix the slop in the shifter shaft, AND check its movement range, something might need shimming. Also I would consider adding 2 detents and a detent bullet and spring, that is just professional if you rely on it staying in gear when vibrating etc. Re the blade popping off the wheels, do you have bands? The wheels should have rubber band (tyres). I recent put silicone rubber bands on mine, they are really hard and tough but very grippy.
The reason not to is the difficulty of setting up the rotary table on the small tool grinder table.I just measured the balls and they are 5.1mm in a 6.75mm slot, so they are certainly wrong.
I wonder if the gear change lever should rotate through the top so it has gravity holding it in position. Build the fork back up with silicone bronze and try it out. Swagged balls are someone’s quick fix.
Somewhere in the shifter mechanism I would put two detents in to hold the rod in the correct in/ out position. I would make a brass bearing block where that steel bracket is, the bracket fixed by screws to the side of the block, that takes the slop out of that 'bearing' and you use the block to make the detent unit and then a simple either mill slots of some sort or two drillings on the side of the shifter rod. And yes I would grind the dogs square using the centre line ie the rotary table not the tool grinder slide.
I seems DoAll did exactly that with a detent on other models of their saws. ruclips.net/video/1t6aH7WTzC8/видео.html Mine didn't have this, but your suggestion is a good improvement.
Just wanted to write same thing. Almost any gearbox that I'v ever seen had some detents/balls to hold fork in appropriate position. And also.. in this position fork should not touch the ring. It sholud engage and then move slitly back, so it will not ware. If there is a backrake on the dogs, they should "pull" clutch together, so fork do not need to be in the contact. We speak about tiny movements in tenths of milimeter... And that screw that is touching variator... Maybe short belt was the reason for that interference? If you put longer belt... lowest position will change. As I can see from the clip this will require to move those two nuts more to the end of the screw, so it will fix this issue.
@@bmalovic Yeah, I found that DoAll added detents on some othe model saws, so I will add some. The old belt spec on the dataplate links to a V5L420 spec, and 42" is 1092mm. I bought the closest standard belt of 1060mm, but now also realise that the motor mount is not standard, so maybe the shorter belt was used to compensate for a higher motor. I need to take a closer look at the whole belt set up one the gearbox is back in.
Not sure if I've seen it correctly, does the gear selector knob shift between high and low in a downward, U-shaped 180° movement? If so, could the weight of the plastic knob along with the shaft play and vibration in use be dropping it out of gear?
is the bit with the teeth somehow just in backwards so the teeth face the wrong way and the ramp is forward? idk it seems like a long shot but i got nothing else
The dog "teeth" have been reground before. The low speed ones done well, which the high speed ones, had been doen before, worn out rounded, and then I did a crap job of regrinding them. I will fix that.
Swapping those plastic guides for a ball bearing one would help as well, I had no end of trouble getting them adjusted then compensating as they wear, with ball bearings you just replace them as you you would indexable tooling. You can even buy and adapt the assembly.
Hell yeah! Americas cup race three one one monitor and Starship FT#5 on the other. Sticking the chop stick catch is pne of the most amazing bits of the control tech ever! Also amazing that they nailed the splash sown in the indian ocean, right next to the target bouy, even with melted flap hinges.
I'd probably just touch up the roots of the drive dogs with a dremel as the faces should be worn to all engage together at once, there again i dont have a tool and cutter grinder 😊
Just an observation. You have too much tolerance throughout the dog engagement. No positive fixed positioning. This may not be the primary issue / cause of disengagement but a place to start. Also, eliminate all ramps
Thanks for looking at this. The selector dog is hardened. The yoke isnt. I suspect that Do-All didn't use balls in the yoke at all. I just found this... www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork Looks like I need to make a new shifter fork, with hardened blocks.
It would be nice to know how the clutches looked when new, possibly not like these🙂 Looking around the internet , it appears that most dog clutches have 90 degree contact with the two sides. (or even a slight interlocking angle) also the back ramp, meant to make engagement easy will infact also kick it out of engagement , meaning that the shifter fork needs to keep them in engagement. so it looks like Yes to all 3 steps that you considered.
@@RotarySMP Yep, would have been in French otherwise. I thought you were Australian, so it was strange to see a machine popping up on the -literally- other side of the world.
(I have _not_ done the math, proper; but...) could you make a "Y" shaped yoke to pickup up the {1st, 2nd and 4th} openings of a -1O- 5 spoke using the kit/parts of your -new- previous puller? While it would tend to lever towards the fingers that are closer together, a 'leg' ...uh ...thicker arm to support the leg of the "Y" could help with rigidity... (facepalms) ...or use a triangle shape so that the load path is fully enclosed by the material, and all the drilling operations are square/perpendicular to the outside edges. -( uh... 1.70!? that can't be right... edit: 1 is not 0.5, me; time go find food! )-
It'd seem that someone has messed with that fork in the past. Those balls could have been added by someone trying (and failing) to solve this same issue.
Certainly. I think the whol shifter fork is a shop made part. But the balls is an original DoAll (crap) design according to other owners. However also used other designs on other models. www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork I drew up a replacement fork yesterday.
firstly, grind the sliding dog clutch till both sides have good hook action. It does not make any sense for the balls to be loose in the forks, they should be fixed and protruding so that the only contact between fork and sliding dog clutch is the balls themselves, that is why there is wear on the fork, it has been touching when it is not supposed to! One can see that the balls should be free to rotate in the fork, but not move in and out. When the fork slides one way to select a gear, because the balls can move away from the direction of movement, it is only the body of the fork that is moving the dog clutch across, but because the balls are not protruding from the fork, they clutch is not being moved far enough into mesh. Phil
@@RotarySMP my feeling is that the balls are original, any chance of looking at a parts list or manual? pointless to retro fit them as a repair unless you can get the protrusion and the pressure of staking exactly right so the ball is free to rotate, with no lateral play.
i would backcut the shoulders for sure, and i think your on thje right track on the worn shifter fork. but you may do an upgrade where you pput some high wear nylon style material instead of the balls, or even just remake the while fork end out of thicker material so there is less slop. i do like the idea of taking the slop out of the shifter lever, maybe a steel bush welded to the bracket to remove slop, and then simular on another support? Good luck either way.
I will certainly remake the shifter, using a solid wear surface instead of those balls. Removing play form the linkage and adding a detent is also on the plan.
They do. I have them, but the lower tire has stretched a little, and had come off just before I shot the clip of removing the blade and gearbox. I need to bond it back on, or get a replacement set.
That old DoAll partnumber on the dataplate links to a V5L420 belt, with 42" converting to 1092mm, I bought the closest standard size which wa 1060mm. I since realised that the motor mount is non standard, so maybe that led to the shorter belt.
The totally messed up drive dogs cut like a monkey did it is the problem. A dremel cutoff wheel would have done better even a file. So the pressure forcing it out is way greater than the angled catches can counter. DUH.
@@RotarySMP have you contacted the Doall customer service? They are still in business and perhaps you could pick their brains as to what the issues could be. Perhaps you can get a service manual for your machine and the correct belts.
@@taranson3057 Got it. Yes on the Red ass :) DoAll have the manuals online, but the gearbox drawing they have is a very distorted scan of a fax. Some of their other saws have forks without the balls. www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork They seem to price parts in EWD (Equivelent weight in diamonds). They list the belt reference on the dataplate, and then a modren spec on their website. www.doallsaws.com/9770-v-belt I convered the 42" to 1060 as the nearest standard length. Not sure why a shorter belt was in it before. Maybe due to the non-standard motor mount?
At 5:34, I immediately realized what the problem was. The spurving bearings were not in line with the panametric fan, therefore the hydrocoptic marzlevanes were not engaging with the pandermic semi-boloid slots in the stator correctly. That easily explains why it was falling out of gear.
LMAO!!! I'll dig into my Rockwell control user manuals, to find the correct adjustment for the reactive current of the unilateral phase detractors.
A turbo encapulator would prevent this
@@seancollins9745You are on to it Sean.
@@JCWren when I realized that there was a joke in there I just about fell off the chair laughing 🤣.
Prat!
For American V belts, the letter in say, a B38 belt denotes its cross section size. The following number denotes the outer circumference, minus two inches in length. That would make a B38 belt 36 inches outer circumference. An X suffix denotes that it is a clogged style belt
Thanks a lot. I couldn't get imperial B (21/32") belts here, so I ordered the closest metric (17mm) size. The DoAll spec on the data plate links to a V5L420 modern spec on their spares website. 42" converts to 1092mm, so i choose the closest standard whch was 1060mm. I since realised that this saw now has a none standard motor mount, so maybe they needed a shorter belt to compensate. I have been informed tha tthe cogged style is wrong for this use case, so I will need to get a different one. Once it is all back together, I will try out the old 965mm and the new 1060mm belts and see which is better, then order a new uncogged belt of that length.
PTFE shoe that fits over the fork to make up the gap bergen the fork and groove in the dog.
Oilyte "buttons" instead of the ball bearings.
Either way you'll need some kind of positive latch/locking mechanism to keep the fork in place if there is no back rake on the dog teeth. Just have to make sure it's not putting pressure on the fork to keep it in place.
Yesterday, I drew up a replacement fork in CAD. The original is beyond saving.
Sadly, I can't offer any useful input for you I but do want to say that I enjoyed your video, so thanks for posting. The comments look interesting so hopefully you'll get some good info from more knowledgeable viewers. Looking forward to the fix. - Heather
Hi Heather, yeah, there is lots of good advice here to work through.
Looking at the wear pattern on the shift fork ( heavy near the shift rod, lighter near the contact points ) suggests to me that the fork is bent or misaligned and therefore may not be pulling the dog clutch fully into mesh or holding it in mesh. I was also thinking that those contact balls may be designed to be free to spin but the balls and their sockets have worn "beyond the wear limit", another possible cause of only partial engagement of the drive.
Good observation Gary. I uspect you are right, I'll check it with a square tonight. You are ceratinly right about the ball retention pockets being worn beyond limits as well. I drew up a replacement yoke yesterday.
Things I'd be considering that might (or might not) help:
1. The balls on the yoke look non-round from wear, so maybe too small
2. The nylon bushing on the faceplate side of the shift lever has a ton of slop
3. The reverse slope on the high speed drive dogs
1. Yep. I measured them yesterday. 6.15mm balls, 6.75mm slot. Plus some flat spots on the balls.
2. Yep, I dont thing that plastic bush is original, it is probably already a repair for a slogged out hole in the sheet metal frame.
3. Yep, that one is on me :)
I drew up a replacement yoke in CAD yesterday.
I have no suggestions but am impressed at how well you explained a complex mechanism.
Thanks for your feedback.
I'm concerned about the slope on the back of the drive dogs. Seems like the moment you stop applying torque (like when you stop cutting) it's possible the blade/wheels momentum will briefly back-drive the gearbox, causing the ramps on the rear of the drive dogs to push the selector vac to the middle.
Good point. Probably why it needs the shifter to latch them and prevent that.
G’Day Mark, I read the 130 comments so far, and concluded I have nothing new to add/suggest…however it’s rewarding to see that you’re tackling this thing. I’m sure you’ll get it sorted! 👍
Hi Doric. Thanks. Did that guy ever get your DoAll back in service?
@@RotarySMP Apparently so. He sent a message to that effect last winter.
@@624Dudley Cool. Thanks for saving one.
Drive dogs on motorcycle gearboxes definitely have back rake to keep the gearbox in gear. That applies to both the drive side and the engine braking side of each drive dog. But those things have a lot of vibrations and sudden load shifts. I wouldn't think that raking the drive dogs could create a problem but you do need to set them spot on to the proper compound angle for grinding to ensure you'll get full face contact on all of them instead of point contact
As I now better understand that the shifter needs to positively hold them engaged, I think it would be better with my dodgy set up to grind vertical to keep it simple, and avoid radius at the root with clearance.
This exact issue happens on the bikes I race. They bend the selector forks slightly due to mis-shifting (forks having no where to go) then they take out the nice edges of the dogs as they don't select properly. New forks that fit well into the slots fix it (they have little wear pads on the good ones, never seen balls I guess this is because they are hard)
@@mandrakejake Thanks. This all helps me work out what to do to fix it.
Between the slop in the fork, and the parent point contact on the dog faces, there looks like there's plenty of opportunity for the dogs to work loose under varying load conditions. Also, I think the relief that had been cut originally is important to keep the engagement fully seated. Any debris, or even hydraulic action of the oil may initiate the dogs decoupling at low load.
Apparent not parent. Silly auto correct. Phones huh?
You have so much patience. I’d love to see a graph of your decision tree. Nothing makes it to the scrap pile. But there has to be a cutoff somewhere. Maybe there’s more old machines here in the US. I’d never consider this kind of work. Cool as it is. I just spent $1k on parts to fix a Mazak 200M that’s 20 years old. And I won’t do a fraction of the work you’ve done on this one old band saw. Very cool work. Thanks for all the videos.
Hi Craig, I guess, being a hobby, and DoAll pricing it's parts in EWD (Equivelent weight in Diamonds), I would rather make parts at irrational cost in time, than buy them :)
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
I gave myself the same puller. The quality leaves a lot to be desired, but I've often been glad to have it. Highly recommended for occasional use!
For next Christmas I can recommend one of these inexpensive inner bearing pullers! You don't need it very often, but when you do, it saves the day! 😉
Good idea. Xmas is coming :)
@@RotarySMP Hopefully your wife is reading along! 🤣
@@chrismayer8990 I'll encourage that :)
If the selector fork held steady position and left minimal clearance at the clutch you'd be golden.
Yep, thanks. I drew up a replacement shifter fork yesterday :)
I just so happen to be working on the same model bandsaw gearbox. If I can supply any photos of my parts, please let me know. Mine appears to be in much better shape then yours.
Hi Steven. Thanks. I appreciate that. Does yours also have the balls in the shifter fork? Looks like other DoAll models have (hardened?) steel weat plates there.
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
Does yours have detents in the change linkage?
ruclips.net/video/1t6aH7WTzC8/видео.html
@@RotarySMP Hi RotarySMP. Yes, mine has balls in the shifter fork, but looks a little different than yours. No, mine does not have detents. Also, no wear plates. I believe that the gear shift lever should be either at a 90 degree left or right position when fully engaged. This "locks" the shift lever in position. Your gear change lever appears to be a DIY repair. Maybe the shifter fork is as well.
On another note, I'm going to change out the output shaft bearing to a double row if I can, for better alignment and rigidity. Think I will also change out the bushing for a needle bearing and inner race. This is how the later gearboxes are constructed. Evidently, DoALL knew this was a problem in the design and improved it.
@@steventimme5268 Yep, that gear change lever was missing when I got my saw, so I made it. It has no detents. I also remade the cam and the cam slot. Once I have the play out of the system, I will ave to see whether it latches in the two engaged position, or needs a detent added.
I drew up a new shifter fork yesterday, and will go for a wear plate design.
@@steventimme5268 Yeah, I would have put in a needle roller if I had thought it through. By the time I realised, Luke was already making the shaft with the pinion to the original design.
Given how little work my saw will see, I expect the intershaft bushing to easily outlive me.
I'm a retired certified millwright (64).
I also used to race sports cars (relevant later).
In my opinion those dog rings need to have rake on them to stay engaged. You stated that you wanted to make them flat. I disagree. You noticed that the low speed dogs had rake. It would make sense that the other dogs also have rake --- no ????
Like I stated above, I used to race sports cars.
The car I owned was a Lola T-360 formula car converted to a full body A sports racer. The relevant point to your video is that this race car had a FT200 gearbox (very expensive to repair and maintain).
This gearbox has straight cut gears with dog rings.
It was very common to lose a gear in a race, the thing would jump out of gear as soon as you let of the gas coming into a high speed corner just before I had to dive on the brakes.
What happens is that the rake on the dog ring and the gear would get smashed because of the violent shifting.
The rake on these parts was 7 degrees.
Even though there was still some "slight" angle on the parts it would not hold because the sharp tip got knocked off and that's all it needed to lose to not hold.
I believe you have the same issue.
You are also correct, in my opinion, to repair the shift fork and those ball bearing ends. You wouldn't want metal on metal contact and the ball bearing would act as the rollers.
Just my opinions. I may be wrong.
Thanks for the feedback on that. The reason I picked up on 0 rack, was that another DoAll owner reported that is how the dogs are in his gearbox. This is only a 1.1kW drive, and gearchange is only stationary.
I will remake the shifter without balls, as later DoAll gearboxs also dropped that design for sliding slippers.
Making a new shift fork is a worthwhile job. Do that for sure. As well as correct the faces on the drive dogs. I'm not as sure about the linkage, but your thoughts are sound. Perhaps add a spring detent setup to hold the linkage in position.
Yeah, turns out DoAll added spring detents on some of their saw models, so I am planning to do that as well.
Belt classification
Z=10mm
A=12.7mm (13mm)
B=17 m
B38 means B (17mm wide) x 38" (38 x 25,4=965mm)
And letters in the end...
Li = lenght inside
La= langht outside
Lp = Ld = lenght middle
That means that you need the belt 17x965 Li
Ask any belt suplyer like OPTIBELT in Austria
Thanks for that. I am not sure if that 965mm belt which came out was the right length though.
The old DoAll spec D9-3770 listed on the dataplate comes up on their website as...
www.doallsaws.com/9770-v-belt
...BELT V 5L420
The 42 inches converts to 1092mm, which Is why I ordered the 1060mm as nearest standard length. I have been informed that I should not use an X (knotched back) belt in this application, so I guess I need another belt.
I'd certainly try to get the 3 engagement surfaces squared up to ensure better contact between the selector and the gear. This would reduce any force trying to disengage the gear. Of course, all that slop in the selection mechanisms is too much and needs to be eliminated too.
Thanks for reviewing this, and your input. Will do.
My opinion is that the drive dogs once engaged, should naturally "want" to stay engaged. So, from your list, I would do #3 first and then tighten up the other issues. :)
That is good logic, but the low gear dogs already have good mesh and back rack, an they were the ones jumping out of gear constantly. I think a saw has enough vibration that you need the shifter to hold the selector in engagement.
I think it’s the yoke given only the ball bearings should be in contact - no wear in the sides which you have.
Making a gearbox sleeve to self hold the gear lever seems wise to take out the yoke lean.
The gearbox was previously run until the intershaft bushing was so completely slogged out that a Woodruf key was released. I suspect that wear on the side of the shifter fork was from when the bushing was deflecting. But year, it is a crap design with the balls an completely worn out, so I will replace it.
I was about to comment at the start of the video that a hacksaw looks faster, then you say the worn out bandsaw is just faster than a hacksaw. Hopefully the repair improves reliability.
Plus this way I got a full core aerobic workout in, reengaging the gearbox a dozen times :)
In a manual transmission car, there are spring loaded ball bearings that seat into detents on the shift arms. Those play a big part in keeping the car in gear. If you add something like that to your shift arm it could help keep it in place. Maybe some kind of friction lock could also work or just a really heave lever flipped so gravity helps keep it in place. It is possible all of the loose components combine with vibration is what is popping it out of gear.
Turns out DoAll added detents on some models, so I think I will do that. I will certainly take the play out of the linkage.
when you put it all back together you should add a car gear lever and a clutch pedal
There is already a pedal on it :) It is for the gravity power feed mechanism.
The main problem, as far as I can tell from your footage, is de shifter fork. Judging by the difference in positioning in the fork, the balls have been added later. I would fabricate a new fork, with minimal play, without balls. I have never seen balls on shifter forks in any gearbox. If the play between the drive dog wheel and the fork is minimal, and the change lever is fixed, the gears will stay in place.
Thanks for taking a look at that Willem. Good point, I had just assumed the balls were part of Do-Alls design.
The balls do reduce shifting friction and wear.
If the original fork wore down so much that it needed fixing like that, then it is definitely a wear zone.
But wear is most likely from incorrect alignment, so there is that...
My DoAll has balls in the fork...
@@larryw5329 Oh, that is interesting. Do you have any photos of your shifter fork?
@@larryw5329 That sounds a bit racy😂
Ha ha 'Wait long enough and it fixes itself....' as a fellow procrastinator (I think I'm at PHD level) I understand COMPLETELY!
Hi Neil, the problem is my procrastination has works often enough that it seems like a valid method :)
Years ago,an author I admire came up with the term. 'Intelligent lethargy'. As in,sometimes problems solve themselves. With people problems, surprisingly often. With things mechanical, less so. A noisy bearing can after all be solved by replacing the entire transmission. But only if you have a spare transmission. And so forth. Good luck with this. @RotarySMP
@@paulmanson253 Well put Paul. I tend to forget mechanical bits are more consistant than humans :)
It looks like someone before was chasing the same issue and put a ton of rake on the selector. This seems like a patch on another issue, the selector fork shouldn't have much play at all. I agree with the other comment that disengagement may be because of brief backdriving when you take a load off.
Also, the rounded shoulder on the side you reground is a no-no. I would aim for a very slight back rake, maybe 5⁰, to make them hook together. Not to keep them engaged, but enough to pull then together should they meet in a slightly off-engagement position. You wouldn't want the selector fork to be under constant load while cutting, it should just keep the parts in a place where they won't be able to disengage - otherwise it will wear out rapidly.
Thanks for you inputs. You are right. When I first did the gearbox repair, I incorrectly thought the shifter was only for gear changing, but now see it is important for retaining the gears engaged. That oldshifter is toast. I drew up a replacement yesterday.
I didn't watch the the older video on this, but has this shifting mechanism a sort of end-position-arrester.. like a over center latch or a spring loaded ball + groove?
Is there anything in this whole setup that keeps the drive-dog in its Hi/Lo gear position respectively?
Maybe that feat was caused by the loose fit of the lever in the past? A sort of over-center thing.. but stuff wears out over time.
What I mean is - if u put in a bushing and make it too rigid it might not work as intended?
Sort of. The slot which the excenter rides in nips up at both ends of rotation.However, that was not enough to stop it falling out of gear (due to the shifter fork wear).
What is holding the drive dogs engaged while the machine vibrates during the cut?
It seems to me either you need a back rake to pull them towards each other or you need some kind of spring in there.
I think that it is supposed to be that shifter fork, but it is all so slogged out, that it fails to retain the shifter in position. I drew up a replacement fork yesterday.
With all the space around the drive fork it seems like there is a thrust bearing/washer that is missing. Maybe the previous owner lost it and tried to take up the space by staking the balls in?
Also, I have a hunch that the bracket that holds the selector arm is not stock, and that is contributing to the excessive play.
Good points. I hav no idea what the original tolerances were, but these are 6.15mm balls, in a 6.75mm slot (seems excessive), but the balls are so poorly retained now, that they play is a couple of mm. The yoke looks a bit bent, and also has a 1/2mm of wear. I drew up a replacement Yoke yesterday.
I think that bracket is probably original. DoAll had some pretty agricultural design practices. :)
B is the belt width (21/32"), X = cogged, and 40 is 40" long
Very interesting. Looking forward to watching the grinding.
Hope I do a better job on it this time. :)
Recutting the shoulders seems to be more like something to do with a nice and sharp endmill than a grinding disc. And indeed, the fork needs some attention too.
Hi Michel, it is hardened steel, I need to remake that fork.
@@RotarySMP Ah, OK. That makes sense.
@@RotarySMPthat wouldn't be too much of a problem for a carbide end mill though, but on reflection grinding is the way to go although I'd go diamond grinding blade myself.
There must be an undercut or a torque applied will drive it out. Also is there a detent ball holding the shaft from just sliding out.
There are other opinions that vertical dog faces also work (I will still need to grind the high speed side). No there is no detent system. I will probably add one.
Well, that`s the issue, the gearbox should not be driving your nuts - but the bandsaw blades... You just gotta figure out how to decouple it from your nuts and onto the saw-drums... Quite the simple solution...
Edit-
Also, i would leave the back-rake on the dogs... That seems to be extremely sensible and useful... Pure 90deg makes sense, as it should never jump out by itself, but a biting rake wants to pull the two together - which is better if there is any wear...
Cheers; Best regards!
Steuss
Thanks Steuss. You are right there. I wont regrind the nice flanks with back rack on the low speed dogs, but will regind the high speed dogs, to give nice flat and vertical faces.
That shifter fork is toast and wore out beyond repair.
Make a new one and new balls.
Think the balls maybe wrong size as well.
**I just read other comments , like other guy said balls may not be original equipment.
Also believe the opening in fork is wore way to big.
Believe it should be symmetrical
Good input, thanks. I think you are right.
Gears when driving through dogs should always pull together. If a selector is holding the gears together with its drive it wears out very rapidly. There need to be equally spaced radial positions for the dogs. so it locks into any position during rotation. At worst the drive faces on the dogs should be 90 deg but that is if the gear is being pulled together with its lead. For the sort of load it is taking you could easily hold it in position with a bronze selector fork and a external gate on the selector. It really depends on what sort of loads you intend to use.
As for the wheels you usally have a radised contact face with its crest in the center, drive and idler.
Thanks for looking at that and giving your feedback.I suspect those ball bearings in the selector yoke is not Doall original.
I've never seen a shift fork with steel balls in the tips before, that looks very much like a badly executed DIY bodge to me. Note how one hole is very close to breaking out of the edge of the fork. Steel shift forks would typically have a pad of bearing material (e.g. bronze) on the ends. The damage to the ball's surface with numerous small flats show they aren't spinning within the fork, and instead will be scoring the shift hub.
I have feedback form other DoAll owners that this is an original DoAll bodge. I agree it is a crap design, and other DoAll models didn't use it.
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
I drew up a replacement fork yesterday. I am unsure whether it is better to make a case hardened part, of braze on bronze slippers.
I just rebuilt my DoAll. I found that I needed to reduce the spacing between the low range and high range dogs. I did that by inserting a shim on the output shaft between the bearing and gear. Also your shifter fork might not have the correct ball size... i didn't measure my fork but yours seems to have too much slop inside the dog selector slot. Good luck.
Yeah, I just measrued them, and they are 5.1mm balls in a 6.7mm slot, with lots of slop in the ball retention.
I think I would square the drive dogs up. I would get rid of the ball bearings on the shift fork ends in favor of Bronze brazing the sides of the fork and re-machining it for a running fit in the groove. And finally remove as much slack as possible from the rest of the linkage. The B38 in the old belt is all you need to match for the length.width. The X in the new belt part number denotes a notched back belt. I once bought a cutoff band saw cheap because it made a lot of rumbling noises while running. The previous owner had replaced the belt with a notched back belt and as the belt wore, the notched sections turned into little bumps making the rumbling noise. Replacing the belt with a smooth backed belt solved it.
Thanks for your excellent inputs.
I'll be more carefull this time to get a nice flat grind on the dogs.
You are right, those balls are a crap design. Even if correct, the peened retention makes for point loads which would wear out fast.
Do All used hardened blocks on some saws...
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
.. so I drew up a replacement fork yesterday. Undecided whether to go for a hardened steel fork or bronze wear surface.
DoAll also added detents on the linkage of some saws...
ruclips.net/video/1t6aH7WTzC8/видео.html
...so I will add some to mine as well.
Thanks for the belt knowledge. I didn't know that, and got the wrong belt. I'll get another one.
I don't like all that slip in the shifter fork. I would like to see a better detent for the shifter as well. I was not able to find Homer on Ios but I did find allot of fun trails that lead to beaches there and enjoyed the ATV driving there.
Hi Robert, Yeah that shifter fork is toast. I had incorrectly concluded it was just for shifting when I first did the box, but now understand it is what holds the gear engaged. I drew up a replacement ysterday.
I don't see how those balls could be expected to work, so I find myself in the "not original" camp.
They don't have anything to push against in the fork (other than a bit of scruffy peining)
Balls in each side into blind holes (offset from each other) might work.
But maybe look at brass-facing the fork with TIG brazing and machining to be a nice running fit.
I am somewhat surprised that there seems to be no sign of any sort of detente. Maybe the ball handle is a replacement and the original one was heavier?
Hi Andy, given your motorbike experience, I was hoping your would give me your feedback. Thanks.
I have feedback from other DoAll owners that it is original, but agree it is a crap design. Even if done "well", the staking around the balls leads to point loads which will wear fast. The balls are only 6.15mm in a 6.75mm slot, so there would be a far bit of play even if the balls were more constrained. DoAll used what looks like hardened slippers on some other saws...
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
That existing fork is toast, so I drew up a replacement yesterday. I am at two minds whether to go with soft bronze slippers, or hardened steel, as it is well lubricated.
DoAll also used detents on some other models of saw...
ruclips.net/video/1t6aH7WTzC8/видео.html
...so I will add some.
The ball handle and sifter rod is a replacement, as I made it :) The original was missing when I got the saw, and would have been just a rod with a 90 bend in it. I am pretty sure the plastic bushing in the frame is also a previsous mod, as the original rod likely slogged out the frame hole.
Certainly not an expert, but I think I agree with you that it's both the brackets and the selector fork. If the balls are meant to be the bearing surface between the fork and the dog gear groove, then there's a ton of wear on all the other surfaces that shouldn't be making contact. The balls also look like they're showing a lot of wear. I'd expect the bracket play isn't maintaining thee axial clearance for the fork, while the worn balls are allowing excessive side to side movement. I'd guess the fork is twisting and binding under load because it has the room to do so, and that's what's letting the dogs disengage. New fork with oversized balls to fit the worn slot, and fix the brackets to hold it in place.
Good inputs. That shifet fork is toast, and I will make a replacement. DoAll used the balls on some saws, but hardened blocks on others. I drew up a replacement fork and will make that, and then address the play in the linkage as well.
The selector balls look like they've been replaced and should be a larger diameter so the selector fork has less play. The current amount of play looks enough for the dog to slide out. Regarding the band jumping out, can you tilt the driven wheel back so the band will tend to stay on, instead of walking its way off.
I wonder if the selector balls were even a Do-All feature, or added by one of the previous owners? There is no adjustment on the driven wheel, except by shimming the gearbox. I'll look at doing that when I reinstall it.
@@RotarySMP If the balls were OE by the looks doall would have put a bit more meat around them, in any event the 'oles they are in a egged out. Make a new selector fork that fits the shift groove better and arrange some positive locking in each gear if you can too. The dog clutches should be square or ever so slightly undercut, undercutting used to be a common racing mod for motorcycle gearboxen to improve gear locking although it does make the dogs reluctant to shift out of gear, not that you are making clutchless down changes on a bandsaw though. 😀
@@alan-sk7ky Thanks Alan. I am tending towards a replacement, ball less yoke, and no undercut.
@@RotarySMPI was going to suggest some bronze pads instead of the balls. Less chance of a balls up! 🤣
@@julias-shed I just found a picture of the original shifter fork. Obviously made of Platinum!
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
Looks like I need to make a new shifter fork, with hardened blocks.
The shifter fork is the culprit alright, I think. Those balls had flat spots by the look and were very sloppy fit in the slot and the fork, easily enough play for it to disengage under load. They have likely been replaced judging by the staking and may be undersize from the original. I'd go for some replacements a size (or two) up that are a close fit in the slot. How much side play is there in the shift fork shaft? The scoring on the fork says quite a lot, it runs in another bushing? ovaled out? In other words, all the thoughts you had ;) You could even consider adding a third ball in the scored area of the fork to maintain planarity with the slot. That staked ball is a weak point in the design, the staking contact points with the balls are just a thin lip of steel. If you can't get it tight and robust, i'd be tempted to ditch the balls and braze on a couple of bronze slipper pads instead with a good surface area. E.G. like a motorcycles' shifter fork. A detent mechanism somewhere for engaged/disengaged would also be very useful.
Thanks for your design review. Very helpful. The shifter shaft has a nice sliding fit. It is not worn out. But since the balls are not restrained, there is a couple of mm of sideways play. The balls are 6.15mm and have flat spots, while the slot is 6.75mm. I don't have any replacment balls in a better size, and agree that it is not a very robust design anyway.
DoAll used shifters with hardended blocks instead of balls on some models, so yesterday I drew up a replacment fork like that. As it is a well lubricated location, I am at two minds whether to use hardened slippers or bronze.
@@RotarySMP Right, so the scoring is a result of the ball hitting the limit of the slot face but the fork continuing to move due to the play between ball and fork. Yes I think the pads are the way to go, either type would work well I'd say given they are constantly bathed, 6 of one 1/2 dozen of the other.
@@m3chanist I was thinking some more about it, and think that bad surface wear on the shifter fork cauld also have been caused back when the intershaft bearing was so slogged out that the output shaft (carrying the selector ) was misaligned.
Since my heat treatment oven is dead, I guess brazing on bronze wear pads is more realistic at this point.
@RotarySMP Sounds like a plan. 👍 I envy your doall and it's gearbox, I have a wood saw that I converted with a 1kw DC motor and speed control I repurposed from old rock tumbler, it work OK but I suspect you have much more low speed torque.
I was looking at the selector yoke and was noticing that the cutout in the center doesn’t match the wear marks i’m seeing above it. Is there a chance that it was a home made piece to replace the original?
It is welded to the shifter shaft. The replacements from DoAll appear to be bolted, so it is most likely shop made.
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
Other owners have reported that the design with balls is a DoAll design, but it seems like crap.
I would put significant undercut on all the drive dogs, like an angle of 10 to 15 degrees. There is really no reason not to, because you never need to shift it OUT of gear when using a high load.
I would replace the 2 balls because they are visibly trashed, AND leave them able to rotate which should help to reduce flat spots and overall wear. I suppose they need to be peened so they just rotate freely, but still have some ball hanging out each side.
You might need to go up in ball size to allow for wear in the shifter groove.
Then fix the slop in the shifter shaft, AND check its movement range, something might need shimming. Also I would consider adding 2 detents and a detent bullet and spring, that is just professional if you rely on it staying in gear when vibrating etc.
Re the blade popping off the wheels, do you have bands? The wheels should have rubber band (tyres). I recent put silicone rubber bands on mine, they are really hard and tough but very grippy.
The reason not to is the difficulty of setting up the rotary table on the small tool grinder table.I just measured the balls and they are 5.1mm in a 6.75mm slot, so they are certainly wrong.
I wonder if the gear change lever should rotate through the top so it has gravity holding it in position. Build the fork back up with silicone bronze and try it out. Swagged balls are someone’s quick fix.
I tried it both ways, but the vibration prevented it for staying at the top. Even clamped in place, the selector still fell out of gear.
Somewhere in the shifter mechanism I would put two detents in to hold the rod in the correct in/ out position. I would make a brass bearing block where that steel bracket is, the bracket fixed by screws to the side of the block, that takes the slop out of that 'bearing' and you use the block to make the detent unit and then a simple either mill slots of some sort or two drillings on the side of the shifter rod. And yes I would grind the dogs square using the centre line ie the rotary table not the tool grinder slide.
I seems DoAll did exactly that with a detent on other models of their saws.
ruclips.net/video/1t6aH7WTzC8/видео.html
Mine didn't have this, but your suggestion is a good improvement.
Just wanted to write same thing.
Almost any gearbox that I'v ever seen had some detents/balls to hold fork in appropriate position.
And also.. in this position fork should not touch the ring. It sholud engage and then move slitly back, so it will not ware.
If there is a backrake on the dogs, they should "pull" clutch together, so fork do not need to be in the contact.
We speak about tiny movements in tenths of milimeter...
And that screw that is touching variator...
Maybe short belt was the reason for that interference?
If you put longer belt... lowest position will change. As I can see from the clip this will require to move those two nuts more to the end of the screw, so it will fix this issue.
@@bmalovic Yeah, I found that DoAll added detents on some othe model saws, so I will add some.
The old belt spec on the dataplate links to a V5L420 spec, and 42" is 1092mm. I bought the closest standard belt of 1060mm, but now also realise that the motor mount is not standard, so maybe the shorter belt was used to compensate for a higher motor. I need to take a closer look at the whole belt set up one the gearbox is back in.
Not sure if I've seen it correctly, does the gear selector knob shift between high and low in a downward, U-shaped 180° movement? If so, could the weight of the plastic knob along with the shaft play and vibration in use be dropping it out of gear?
Thanks Dieter, but I isolated that by clamping the lever in each position, and it still fell out of gear.
@@RotarySMP Ah yeah. I'm sure you'll figure it out, you're nothing if not persistent.
@@DieterTheHorst Thanks :)
is the bit with the teeth somehow just in backwards so the teeth face the wrong way and the ramp is forward? idk it seems like a long shot but i got nothing else
The dog "teeth" have been reground before. The low speed ones done well, which the high speed ones, had been doen before, worn out rounded, and then I did a crap job of regrinding them. I will fix that.
I think the main problem is you converted your Do-All to a Do-Some
More of a Dolittle, Mel :)
Swapping those plastic guides for a ball bearing one would help as well, I had no end of trouble getting them adjusted then compensating as they wear, with ball bearings you just replace them as you you would indexable tooling.
You can even buy and adapt the assembly.
Hi Brendan, do you mean the plastic guide under the info plate on the shifter?
@@RotarySMP no for the blade.
I have no advice on gearboxes
@@brendanshorter5550 The blade guides are not plastic. They are hardened steel.
@@RotarySMP I recall you getting spares off a viewer now, making my entire comment moot
@@brendanshorter5550 Not moot. I have wondered about ball bearing guide set up, but this seems to work okay.
Did you see the Starship 5 launch today?
Hell yeah! Americas cup race three one one monitor and Starship FT#5 on the other. Sticking the chop stick catch is pne of the most amazing bits of the control tech ever! Also amazing that they nailed the splash sown in the indian ocean, right next to the target bouy, even with melted flap hinges.
I'd probably just touch up the roots of the drive dogs with a dremel as the faces should be worn to all engage together at once, there again i dont have a tool and cutter grinder 😊
Just an observation. You have too much tolerance throughout the dog engagement. No positive fixed positioning. This may not be the primary issue / cause of disengagement but a place to start. Also, eliminate all ramps
Thanks for looking at this. The selector dog is hardened. The yoke isnt. I suspect that Do-All didn't use balls in the yoke at all.
I just found this...
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
Looks like I need to make a new shifter fork, with hardened blocks.
It would be nice to know how the clutches looked when new, possibly not like these🙂
Looking around the internet , it appears that most dog clutches have 90 degree contact with the two sides. (or even a slight interlocking angle)
also the back ramp, meant to make engagement easy will infact also kick it out of engagement , meaning that the shifter fork needs to keep them in engagement.
so it looks like Yes to all 3 steps that you considered.
Thanks for reviewing that plan Steve. I appreciate the confirmation.
How come you have Dutch text on your stop button?
The saw came from Begium. I believe it was originally in their military, on the Flanders side I guess?
@@RotarySMP Yep, would have been in French otherwise. I thought you were Australian, so it was strange to see a machine popping up on the -literally- other side of the world.
@@Stefan_Van_pellicom I am a Kiwi in Vienna, so the saw has not moved that far from Flanders.
Where is preload spring for the dog gear?
There is none on this model.
The drive dogs need a negative rake as when under load the dogs will tighten together and hold the engagement.
That seems logical, but it was reported that DoAll used 0 rake on these originally, and had the shifter hold the selector dog in place.
(I have _not_ done the math, proper; but...) could you make a "Y" shaped yoke to pickup up the {1st, 2nd and 4th} openings of a -1O- 5 spoke using the kit/parts of your -new- previous puller? While it would tend to lever towards the fingers that are closer together, a 'leg' ...uh ...thicker arm to support the leg of the "Y" could help with rigidity...
(facepalms) ...or use a triangle shape so that the load path is fully enclosed by the material, and all the drilling operations are square/perpendicular to the outside edges.
-( uh... 1.70!? that can't be right... edit: 1 is not 0.5, me; time go find food! )-
I could make a replacment yoke, but that is too much faffing around to remove that bearing. The 3 spoke puller worked well enough.
It'd seem that someone has messed with that fork in the past. Those balls could have been added by someone trying (and failing) to solve this same issue.
Certainly. I think the whol shifter fork is a shop made part. But the balls is an original DoAll (crap) design according to other owners. However also used other designs on other models.
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
I drew up a replacement fork yesterday.
firstly, grind the sliding dog clutch till both sides have good hook action. It does not make any sense for the balls to be loose in the forks, they should be fixed and protruding so that the only contact between fork and sliding dog clutch is the balls themselves, that is why there is wear on the fork, it has been touching when it is not supposed to! One can see that the balls should be free to rotate in the fork, but not move in and out. When the fork slides one way to select a gear, because the balls can move away from the direction of movement, it is only the body of the fork that is moving the dog clutch across, but because the balls are not protruding from the fork, they clutch is not being moved far enough into mesh.
Phil
Thanks for your input on this Phil. I think you are right. I had assumed that the balls are original, but maybe this was shop mod?
@@RotarySMP my feeling is that the balls are original, any chance of looking at a parts list or manual? pointless to retro fit them as a repair unless you can get the protrusion and the pressure of staking exactly right so the ball is free to rotate, with no lateral play.
@@philhermetic There is only a really bad scan of a scan of the parts catalog. Even DoAll has that on their website.
i would backcut the shoulders for sure, and i think your on thje right track on the worn shifter fork. but you may do an upgrade where you pput some high wear nylon style material instead of the balls, or even just remake the while fork end out of thicker material so there is less slop. i do like the idea of taking the slop out of the shifter lever, maybe a steel bush welded to the bracket to remove slop, and then simular on another support? Good luck either way.
I will certainly remake the shifter, using a solid wear surface instead of those balls. Removing play form the linkage and adding a detent is also on the plan.
Do metal bandsaws not require tires on their wheels?
They do. I have them, but the lower tire has stretched a little, and had come off just before I shot the clip of removing the blade and gearbox. I need to bond it back on, or get a replacement set.
@RotarySMP ooooooh i see. I saw that and thought "well there's yer problem!" 🤣
@@arimadx Yeah, the crowning on the Alloy wheel would not last long without the tire.
B is the belt width 40 is the length there a lots of online belt length calculators.
That old DoAll partnumber on the dataplate links to a V5L420 belt, with 42" converting to 1092mm, I bought the closest standard size which wa 1060mm. I since realised that the motor mount is non standard, so maybe that led to the shorter belt.
Also would like to add , your channel is Awesome
Thanks very much for your kind feedback.
The totally messed up drive dogs cut like a monkey did it is the problem.
A dremel cutoff wheel would have done better even a file.
So the pressure forcing it out is way greater than the angled catches can counter. DUH.
Yep, it is toast. I will make a replacement.
i love that method too but works very bad
Yeah!
Glad to see your getting it done. How do the gears look?
Hi Luke, I don't need to pull it down any further, which would expose the gears you made, but from what I can see, they still look perfect.
@@RotarySMP that’s good then. Hopefully it will be an easy fix for you :)
@@LCalleja I hope I can get it sorted this time. I am sick of it not working properly.
@@RotarySMP yes it gets tiering when things are not working properly especially when they work just enough to be slightly useful
@@LCalleja I failed to understand how the shifter is held engaged by the shifter fork. Now I think I get it.
interesting problem you have there. I concur, I think you need bigger balls.
Thanks Rick :)
If I had a saw that jumped out of gear or if the blade jumped off track it would give me the red ass.
Not sure what that means, but it sure is frustrating.
@@RotarySMP its an old baseball term that would refer to someone becoming intensely frustrated and angry.
@@RotarySMP have you contacted the Doall customer service? They are still in business and perhaps you could pick their brains as to what the issues could be. Perhaps you can get a service manual for your machine and the correct belts.
@@taranson3057
Got it. Yes on the Red ass :)
DoAll have the manuals online, but the gearbox drawing they have is a very distorted scan of a fax. Some of their other saws have forks without the balls.
www.doallsaws.com/parts-store/spare-wear-parts/transmission-gearing/111449-shifter-fork
They seem to price parts in EWD (Equivelent weight in diamonds).
They list the belt reference on the dataplate, and then a modren spec on their website.
www.doallsaws.com/9770-v-belt
I convered the 42" to 1060 as the nearest standard length. Not sure why a shorter belt was in it before. Maybe due to the non-standard motor mount?
👍👍😎👍👍
Thanks Joel.
Did you just watch the SpeceX Super Heavy Booster catch? Incredible !
Starship next !
Hi Andrew, yeah, absolutely bonkers! A masterpeice of control :)