Kearney & Trecker Model 2H Horizontal Mill Rapid Traverse Clutch Repair
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- Опубликовано: 18 июн 2015
- I finally got around to pulling my milling machine apart to see about repairing the rapid traverse clutch which was slipping every time I used it. This shows how I went about rebuilding the clutch pack and reassembling the milling machine. The end results are a great improvement over what I started with, but I still have a few issues to deal with.
My last year of high school I told daddy I wanted to be a machinist but he that wasn't a go plan so I went into medical technology using a lot of the math, that was over 50 plus years ago. Now I have two small lathes which I play with. I enjoy your videos.
OUTSTANDING! I envy your capacity for logical analysis and repair of these great old machines. I am inspired by most if not all of your videos! I am encouraged to take a deep breath and ask myself "what would Keith Rucker do now?"... Thanks...
bentontool When I get in a jam, usually what Keith Rucker does is walk away and think up a new plan.... I make lots of new plans......
“Kerner & Treckey”? Funny. Good info and nice work on the clutch. Thanks for sharing this!
I realize this clip is 2 years old, that said if every thing is in tolerance it has to be your spring load . those spring did not have the proper seats and maybe coil count . There is propley a Mom and Pop spring shop in your area that could steer you in the right direction or make your springs. Keith you ROCK! carry on
There may be something downstream, with the knee, that's causing resistance which is tripping the clutch. Imagine you get a new clutch that is calibrated, you put it in, and the same thing happens.
I'd suggest doing some investigative work on the drivetrain that goes to the knee.
By the way, I've just watched almost all of your videos, and I'm thrilled that you, and some others on RUclips, are sharing your experience. It's an amazing time to be alive, with this capability.
Pretty much completely agree with you - ensure the whole transmission is free and easy to move and in particular the Z axis is well lubricated - the slides, screw, screw thrust bearing and of course the nut.
Failing that, you'd have to turn down the gravity value ;)
Love the old K and T. It was a real work horse with lot of capability. My first teardown as an apprentice was a 50hp. Cincinnati. Boss told me I ws going to run it but first I had to get it running right. Gave me the manual set me at it. quite a learning experience. The wife hated it, I came home covered in oil and grease for two weeks, but i got it running and you could pull a building down with it.
david Boedeker There is now way better to learn a machine than to have to tear it down and rebuild it! Great story!
Excellent breakdown of the problem, and your solution is at least 66.666% effective :), was a pleasure to see someone put something back together with no left over parts, or (much worse) missing parts. Thanks for posting.
excession777 I was excited when I got to the bottom of the parts bucket and everything was back on the machine! Always a nice feeling....
Hi Keith. Really enjoyed the video, so thank you for letting me be part of the repair so to say. I also learned a couple of things! And don't despair about the partial success. Sometimes it takes two to three steps to resolve a complex issue. And now you will have a much better understanding of what else may need tweaking to fix it permanently. I have all the faith that you'll get it done! :)
mictho100 I am going to try and find some even stronger springs and hopefully that should do it.
Keith, as you know I've been doing machine repair for over 40 years. I have done many of these ball-type safety clutches in Hydrotells, K&Ts, Milwaukee's and Cincinnati's. This tutorial gives a good concept of the repair, and you've done a great job of explaining this in a way that most viewers would understand. As always, I enjoy your videos, keep 'em coming!
Your friend,
Cliff
PS: I'll bet you're glad there were no train derailments this time.
Clifford Fender Thanks Cliff - a lot of trial and error involved in a project like this when you don't know the specs to work off of. And yes, I am glad that the train is running as it should again!
Loved watching you show us gear cutting technique. Thank you.
Thanks for taking the time with this great video Keith. Its really interesting to to follow through your various thought processes and practical steps to get you to a conclusion.
David Mallett I do my best with my thought process. I just wish that I knew more about this machine to figure out what is going on.
My dad was a machinist at Kearney & Trecker in Milwaukee in the 40's. He would be happy to know that those machines he worked on are still in operation.
Keith, This video has saved me so much time. I am doing the older 2-H Universal. I did find in the knee that is another slip clutch similar to the one you overhauled. Thank you for postint.
That is absolutely fascinating - simultaneously simple yet fiendishly complicated!
*Great* work Keith getting it as far towards being fixed as you have!!!
+morelenmir Thanks!
Thanks Keith, I'm going to like the Friday night episodes. I enjoyed seeing your work on your K and T. I've never had a chance to use one, but all you YT guys make me keep looking for one.
Ed Texley I need to find a new larger K&T before I increase the demand for them too much and drive the prices up!
Great segment Keith. I am sure a lot of us got great info on your repair. The mass of lifting the knee in the Z is certainly the acid test.. Thank you for sharing this with us. Fred
Fred Miller Thanks Fred!
Thanks for sharing. I enjoyed seeing how it works and fits together.
Love this video and these horizontal K&Ts. I ran a mill like that in the shop I worked in for more than 7 years. These machines were indestructible, lubed them on occasion otherwise they ran and ran and ran.
I would not not bother me much with no rapid on the knee. Most of the work we did on these horizontals was feeding on the longest axis or boring using the shortest axis. The knee was usually only moved during setup and locked.
+cadrmn88 Yeah, I love the horizontals. I cut my teeth one a mill very similar to this one back in the late '80's.
What a shame Keith , I thought ya had it pegged with the ball bearings and spring ! Gets quite $$ working on equipment , 400 to have that fixed is a big WOW .. Thumbs up man , I enjoyed it !!
ShawnMrFixit Lee Thanks - Probably going to try some stronger springs at some point.
Keith the next time you take it apart put a wrench on the knee feed shaft and see how much torque it takes to turn it. The knee hand crank has a mechanical advantage so it might be hiding some hidden resistance like bad bearing or way friction. I really enjoy your videos ànd projects. You, Keith Fenner and others keep us old gear heads happy.
Gord Taylor
Windsor Ontario
Gord Taylor It would take some work to do that the way the crank is built but that is sure an option. I still think the problem is that my springs are a bit on the light side. They were the strongest ones I could find at McMaster-Carr but I could tell they were not as strong as the originals. Thanks to some guys here, I have since found a source for a spring that more closely matches the originals and I will probably replace them again.
Great video,I have come to a point in my life where I no longer stride for perfection, better is just fine any more. Thanks for sharing with us.
jaime vega Good enough is just that, good enough. In this case, I will probably try and do better though as I really hate cranking that knee up by hand....
Have you considered a counter weight system, if done right it would look decent and will make that heavy knee a lot lighter for your limit clutch to pick it up without jarring itself loopy.
Those old mills are insanely masterful feats of engineering. The greatest generation built these with slide rules,clean cut short haired men. No cell phone,no stupid facebook,no twitter. Some of theses machines were designed and built under pressure of WW2. The greatest generation. Our freedom come from them. I wonder if many appreciate these OLD beautiful machines as you do. THese are the machines that build the hardware of WW2 ,The greatest production this country EVER did> > >
I bet the slip on the knee going up it could need oil on the up ways or it could be the lead screw and nut for the UP is stripping.
***** I agree totally about the greatest generation. Knowing that this machine was built in 1942, the only way it could have been purchased was for the great needs of war production. We will probably never know what part or parts this mill cranked out for the war effort, but I would be willing to bet that it was running nearly 24/7 during that period. If only this tired old machine could talk. As far as I am concerned, she deserves to be kept alive and being productive. I hope to one day have the time to completely go through her and give the machine a proper restoration.
Power lift on my Bridgeport didn't have enough strength. I added 2 150 lb nitrogen springs from MC to help the power lift lift the knee. You would no doubt need stronger ones. They've been working for 20 years. Try it, they're cheap. My shop had the exact same mill. I had the same problem. I had a slip clutch come apart too. a ball got in the gears and really messed it up: broke a tooth, bent a shaft...
Keith:
I agree with others that, since you've fixed the clutch, the trouble might not be there any more.
The knee may have some issues like crud or wear in the jack screw or a messed-up thrust surface that's causing undue drag when raising the weight of the knee.
That may have been the trouble in the first place and whoever "repaired" it before just made the problem worse.
Great videos! I'll put you in for a raise. :-)
Maybe there is another gear in the knee that the original bozo put on backwards???
Elden DuRand Hard to say for sure as I have not been into the knee of the mill at all, but based on the amount of force required to raise the knee by hand, I don't think that is the problem. I think that my guessing at the spring pressure required might have missed the mark. I wish I had some specs on what the springs are supposed to be....
Keith Rucker - VintageMachinery.org When you crank up the knee, is it smooth? If not, I'd suspect something's dry or wrong. I like the idea about another Bozo fix being the problem. there could have been a problem with the knee that was repaired wrong then the clutch was suspected and IT was repaired wrong.
I'll bet the junkyards are full of stuff that was Bozo'ed to death. I've resuscitated several cars that were junkyard bound and got a lot of miles out of them by simply putting them back the way they were made. After using them, hey were either sold or just naturally worn out and went to that Great Scrapyard in The Sky.
Nice job Keith for using a copper hammer tapping in the woodruff key. The little things make the big things happen. Nice work too. Peace
A well-done video on your part! Enjoyed watching; as always, thanks’ for taking the time to make this video! And I support this site. ~M
Mike A Drover As always, thanks for watching Mike!
I worked at Kearney and Trecker renewment div. For 28 yrs. and I worked on many,many 2 H machines. I can say for a certainly that clutch part is trash. We tried to machine the holes deeper- no luck, There is a torque for the clutch, but I can’t remember. It’s remarkable anyone still has a part.
Great video, Keith. I really enjoyed seeing the innards of the Kearney and Trecker (not Kearner and Trecky, but you knew that) and how you were able to fix it. An almost elegant slip clutch arrangement, simple yet effective. I don't know what to say about the z-axis problem...many other have suggestions; maybe one of those will work.
Anyway, it is in much better shape now.
Joe
Joseph Magedanz Yes, I know that, but for some reason Kearner and Trecky seems to come out of my mouth even though I know it is wrong. I think that sometimes I have verbal dyslexia...
Hello Keith, very interesting video about getting to learn about the technology and ways of doing of that K&T, I always wonder how things works, this is a great demo...
Thanks, Pierre
Agreed, seeing the guts of the tool and how it works is cool.
bcbloc02 I too truly enjoy tearing things down and finding out what makes them tick when they need a fix...that is if I can get them back together again, LOL! I love how much help taking digital photos of things before and during a repair can be really helpful to an air-head like me.
Thanks for the great tour of those inner workings Keith, Aloha...Chuck.
pierre beaudry Thanks Pierre!
Thanks for the clip Keith. Someone else may have pointed this out already, did see something about a counter spring. Seeing as somebody has had their fingers wandering about the innards of your machine you might want to pull the drive train for your vertical axis down to parade rest and make sure all the gears are turned the right way 'n the bushings aren't binding etc. Moving that much mass up it probably doesn't take much added drag/friction to trip that clutch. Enjoy your channel!
Poncho Villa I have not been able to find any kind of counterbalance on this machine - either on the machine itself or in the parts breakdown. It is possible that they have been into the knee, but I don't think so - no tell tell signs of them tearing into that part of the machine.
really liked this video i think that rebuilding the z axis is the way to go! this is a good step in the right direction!
***** I really think that the problem is that the springs are still not strong enough. I have found another source for them and a size that even closer matches the original ones that I have. I will likely replace them again before tearing into the knee.
Nice repair job Keith. I think I could live with that.
NSTRAPPERHUNTER I COULD live with it, but probably wont....
Way cool! See and understanding how that works and what the problem was makes for a fun and interesting video. But even with your knowledge of how to disassemble it I wouldn't relish having to do it all again anytime soon. Another great one. I find myself giving your vids a thumbs up before I even start watching because I know I'm gonna enjoy it already. haha
Plain 'Ol Beekeeping in Plano, TX Thanks for all of your support for the site! Yeah, I am not looking forward to digging into this machine again, but now that I have done it once, the second time will go much faster! I might even be able to take it apart and put it back together again in a single day rather that having to spread it out over multiple days in the shop. I have found a source for stronger springs and will likely give this another shot as soon as I finish my gear cutting job.
Looks like you are going to be watching this video yourself :)
Funny how this video popped up in my play list just after I watched you on the last job your mill performed before you need to do some more work on the clutch.
Nice acorn nuts for the safe, really adds to the safe. Thanks for sharing. L-00 chuck.
You must have got up before breakfast! Thanks for the video, Greg.
Charles Compton I almost always get up before breakfast. My wife rarely treats me with breakfast in bed.....
Hi Keith, I am going to give you a fix that will not brake the bank. Go by flat head rivets that the stem will go inside of the springs and the head of the rivet will fit the diameter of the hole. You will need to cut off the stem of the rivet because all it is needed for is alignment, the head thickness should be enough to give you more pressure in the springs. You may only need half of the springs with the extra tension. Just a thought
Keith, I saw this video quite some time ago and don't remember if I commented then. I will start by saying that it's fascinating to watch these videos and see the ingenuity that is out there in design. One suggestion I have for you if you have to work on that clutch again. When you are assembling it, put the gear on the stub shaft first and then line up the holes with the detents. This should be much easier to get the balls and springs in place, and you don't have to do any lining up until you are ready to put the clutch plate and the retaining plate in place.
Wow. No idea about how this all works but I loved every minute I watched :-)
Carina Wilberg A woman that loves machines....I love you! Marcel.
Carina Wilberg Be sure to watch his other videos, too...all good stuff. He is very good at explaining what he is doing.
Carina Wilberg Thanks for watching - always fun to take something apart and figure out how it ticks!
Keith
First great video, second if the repair you did helped a lot with other feeds and directions your on the right track . Going up on the knee takes more pressure then anything else.Keep up the great work & video's.
Wayne K Woods I am going to try stronger springs - I have found some more that I am hoping will do the trick!
Keith Rucker - VintageMachinery.org That should do the trick and the right still of spring . Those other didn't look wright . the ends of them anyway. Good luck .
I have been working on clutch-type limited slip differentials of cars.
I believe you are on the right track with trying different springs.
The working principle of this clutch device, as i believe, is as follows:
The main function of the bearing balls in their detent holes in the baseplate is to provide load to the clutch disc as soon as enough differential torque forces the bearing balls off center of their their detent holes. The total friction of this clutch assembly appear actually to be built two fold: First under zero, or light torque, the preload of the springs compresses the clutch somewhat and produces an 'initial friction'. The bearing balls in their detents likely produce another resistance, but judging by the shallow depth of the detents that is quite smaller than that friction from the friction disk.
Upon 'some' differential torque (determined by spring preload and detent hole depth and shape), the bearing ball get pushed out of the hole. While the ball rolls over the crown to the adjectant detent hole, the height difference the ball moves times the spring rate equals the additional friction buildup, which is 'stage two'. Finally, when the table movement is obstucted, i.e. the differential forces become too high, the clutch friction is overcome and the assembly spins. Correctly set up, the characteristics of this design is a friction torque (holding power) that softly feathers against a maximum designed input differential torqe (i.e almost maximum torque still transmitted when clutch is slipping); as opposed to a hold-and-then-break-away design. From a design standpoint this makes absolutely sense to me.
I want to point out that spring preload is likely equally important as total spring force. Staticly, the shape of the detents are only influencing the break away characteristic. But when considdering dynamics, large inertias, like of the knee, may induce even larger peak forces when the balls slide over the detents. The detent's sperical shape and the wear inbetween are propably somewhat less than optimal because the spring is a cushion and together with the friction disk, the friction force follows the input force fluctuations only in a dampened fashion. In essence: the heavier the knee or table, the higher the force fluctuations, the less effective the clutch.
Therefor: i suggest to increase the friction disk preload.
Strax Gasser That is the plan - upgrade the springs. I already have new ones in hand, just have not had a chance to pull the machine back apart again to try them out yet.
@@VintageMachinery Problem with that plan is that an arrangement that protects the table when in rapid elevation is likely to do significant damage to something when in rapid horizontal traverse, but does not have the weight of the table to overcome first.
Hi Keith
I took apart a tool holder for some kind of production mill of some sorts, it had 2 pins on the back side and the way they found a spring that had enough give and still be strong was they used a spring inside of a spring. So possibly if you could locate another set of smaller springs that fit inside the springs you already have, I believe you would what you need to cure the problem, hope this helps. John
thanks for sharing. i would have thought the springs had caps, concave shaped.
Keith, the clutch slipping in the Z axis after you have rebuilt it, but operating okay in the X & Y, tells me that the slipping in the Z is a symptom of a problem further along the power train toward the knee. There must be something in the knee vertical track/jack screw that is binding and causing the clutch to slip. Looks like not only Adam Booth, but you also have an appointment with a 'bad' knee! Great video.
Don't really think it's more then the weight of the knee overcoming the clutch. When he operated the knee with the hand crank, it seemed to work fine, which leads me to believe it's just the weight of knee going in the up position just being a little beyond the clutch setting. Remember knee worked fine going in the down position in rapid travers, so really think it's the weight going up!
Fred Newman Yes that could very well be the problem. However the vertical track that the knee travels in, may very well have a binding problem in the elevation mode and be free in the depress mode. The manual direct connect hand crank can transmit much more torque that masks the binding. Looking forward to Keith trouble shooting the problem further and finding the cause. Cheers.
Rain Coast I still think the problem is with the springs. Just not strong enough yet. Lifting the knee is the hardest job the rapid traverse has because of the weight of everything. Considering we fixed the problem in the other two axis but not the knee tells me that we just don't have the right spring in there yet. Besides, I have worked many of these mills over the years and know of two others near by me that I have played with recently. I can tell by hand cranking the knee that the problem is not with resistance there.
Hi Keith. A really interesting episode. Keep up the good work :-) Michael
Gentlebear Thanks!
I like that your going to be posting every friday
David Howard I am going to try my best to keep that schedule.....
Hell I'd just run it till the cows come home. Wouldn't worry about it. Z-up is the only problem and you can manually do it so id just call it fixed. If you used that mill all day every day that's one thing but you don't. Great vid Mr. Rucker.
tharp78 That is sure and option, and for the short term, that is likely what I will do. But I have found a source for some stronger springs that more closely match the originals so I will likely tear into her again and give it another shot.
I have that exact same mill with the same problem. I do not use the vertical drive either. We use that mill every day all day, cycling about every minute or so. Remember its 60 years old and still running, They don't build them like that any more. Lets see if some CNC can do that 60 years from now. I used springs from an old tapmatic tapping head that was laying around. Worked great, still running everyday, knock wood
jim sanker Yeah, I doubt many of the machines being built today will last 60 years. If the machine does not wear out, the electronics will fry at some point and you will be screwed. Engineered obsolescence....
My latest video - fixing up the K&T milling machine....
I do not recall the details, but you should be able to duplicate springs if you use wire of the same gauge, and wind them the same length and diameter and number of turns. Some of those factors may not apply, it must be 20 years since I saw that info. The info might be in Machinery’s Handbook. The CD version is said to include older info that is out of use. An old outer bearing race is good for pressing curved surfaces like that in a vice so you can hold the assembly offset to allow room for installing the snap ring. Automatic transmission shops use equipment for assembling clutch packs I do not know if they use one that fits. Or some rig with a big C clamp.
Right on schedule post, Keith :). They surely do not make machines like that any more. Lovely piece of mechanics. Nowadays it's all stepper motors and electronics.
I was interested to see you had 8mm bearings. These are standard loose bearings for bicycle hubs. Maybe the previous butcher -- I mean owner -- got his bearings at the local bike shop. Cheaper than MacMaster-Carr.
Juan Rivero As a bicycle mechanic for 5 years, I have to intensely disagree. Every bike hub (and bottom bracket and headset) I've ever worked on (and there have been hundreds of them) use imperial sized loose-ball bearings. Even though our shop was in USA, this still includes Japanese/Malaysian/Singaporean parts from Shimano, Italian/Taiwanese parts from Campagnolo, American/Taiwanese/Chinese parts from SRAM, and everything else under the sun, including Spanish, French and Canadian domestic parts. "Sealed bearing" assemblies were always metric sizes, but loose balls were always fractional inch.
Also, the loose-ball bearings used on bicycle parts are exclusively sized from 1/8" to 1/4" by 64ths, so you certainly wouldn't find any 5/16" or 8mm bearing balls at a bike shop.
I can't speak for motorcycle shops, but those bearings did _not_ come from a bicycle shop.
Juan Rivero We will probably never know where those bearings came from or why they were used. All I know is that they were wrong....
Keith a washer between the balls and springs should stop the springs from splaying out over the balls and keep the extra pressure on the clutch plate. Nice work don't let it beat you.
Steve Wylie I have found some springs that I think are a better match to the originals that I will probably swap out after I finish this next job on the mill.
I watched your video and I took note that the steel balls were larger than 5/16". I would imagine that through the years someone had changed out the original factory balls for a larger size taken from a ball bearing which are based on a metric system. Because the balls were larger, he would have had to bore out the guide plate where the springs are located. The 5/16' balls, being smaller are not being supported properly and that is why it is slipping.
Large horizontal mills that I've worked on have a counter balance that takes the effort off of lifting the z axis. Maybe this ol' bugger used to have a spring assist or some such?
It seemed to ask a lot of force from the press to get the gear with the holes for the bearing balls all the way down over the bearing balls. whilst on your bench, before that, the gear seemed to drop down all the way with no obstruction. My first reaction noticing that was that your bearing balls were not aligned properly with the gear, and maybe an end part or two of a spring got pressed in between a ball and the holeside. I am not shure what happened, but it seemed not to go natural with the pressing, because the gear should have dropped down over the springs and the balls with no problem. This may be caused by the whole stack of components not beeing able to rotate free under the pressure, and thus not beeing able to align itself. maybe there is a beginning for you when you think over the the partial failure of the clutch repair in this.
You made quite a good video on this rather difficult to film project by the way. Totally clear and with great continuity. compliments for that. Cheers from the Netherlands.
Flip de boer Keith. Read this.
I noticed this too and how after the clip was in it still was not all the way down in it's home position. Maybe a spring end got hung up but I think once the clutch spun they all would have seated. I think the clutch material and the springs need replaced. Also not sure on how you would "calibrate" it short of adding spacer shims before the snap ring. Maybe as a cheap fix he could add a few shims to it to both take travel out of the springs to hopefully stiffen them up and apply more pressure to the clutch plate.
Flip de boer Something to sure think about. I still think that the root of the problem is the springs still not being strong enough. It will likely come apart again, but not until after I finish the project I need the machine for.
Hey Keith, I'd like to offer you a suggestion that might save you some headaches. Next time you go to rebuild that clutch you might try dropping the bearings down through the gear instead of trying to drop it down on them. If the cylinders they ride in are the same top to bottom they should just drop right through instead of having to fight with it the other way around. Also, you might look into sewing machine parts to source new springs. I've repaired a few of those in my years and I know they usually contain some beefy ones. Meantime, thanks for the interesting video. I never knew there was a clutch of that kind on the rapid of any machine. I always thought they expected the people who operate them to just be smart enough to not crash the knee into something. Cheers buddy.
40:35 For Z up, you can always use power feed set at a high speed. Still slower than rapid but still less effort than cranking yourself !
But I would say give the whole power feed drive a really good lubing esp the Z screw, screw thrust bearings & nut. If you can get the whole transmission running with less friction, it'll be a step in the right direction.
I think I'd take some drill stock that fits nice in the holes in the gear where the springs ride. Use it to make some shims to ride on top of the springs to increase the spring pressure. The replacement springs looked like they had open coils at the ends. I seem to remember the other springs were closed coil. That would change the pressure quite a bit because the ends are not seated tight against the ball or face plate.
***** I like that approach as an alternative to new springs with the proper ending, since this is an older machine due for retirement or a new home sooner than later...
2 knuckleheads didn't like this video? Really? Great job as usual Keith!
Jon Hare There are always a couple of guys who give me a thumbs down on everything I do. I guess they just don't like me for some reason. Oh well, the thumbs up override them by a large percentage!
I'm sure someone already noticed this, but 8mm is nowhere near .020 in. larger than 5/16. It's more like .0025 in. Just a slip of the tongue, I'm sure. Otherwise, fantastic work ! Really like your videos.
I've got a KT just like yours, when I bought it, - it had the same problem, so what I did was switch two wires on the power box to reverse the motor, and then I reached around and reversed the spindle direction, and everything has worked fine ever since. ~ hope this will work for you
Blackaboe My motor is running in the correct direction, that is not the problem.
Keith he is not saying your machine is working in the correct direction or not. What I think he is saying is the tiny holes get ramped up when always climbing out in the same direction. So running the motor in the reverse direction is just like the mill being brand new in reverse.
Great job Keith!......as mentioned....I think the open coils on the top end of the springs may be an issue. I'm not sure how it would affect the geometry of how deep the balls are seated, but the thought of making a shim ring with the 16 ball holes to fit on the bottom. The shim should increase the spring pressure a bit, and eliminate the worn groove of being a problem.....may be something to think about. Jim
Jim Liechty I think I am going to look for some stronger springs....
Hi Keith!
In don't know if you've already gotten these thoughts and ideas but I'll share them anyway...
First of all, before you take the springs out of the clutch again it would be really interesting if you could put a torque wrench on it to see what the slip torque is right now, and then test again after the spring change to see the percentage of increase. It probably makes it easier for you to decide if you've gotten enough increase to dare put it together again.
Would it be possible to put a set of smaller springs inside the big springs to get that little extra if you don't seem to get quite enough pressure? Maybe not the best solution but hey - as long as it's working it beats 450-600$ any day in the week.
The tool you made for the spring clip, wouldn't it be possible to turn a relief in it just over the thickness of the spring clip, so that the actual pushing is done on the other ring and the clip just comes along with it?
Just some ideas I thought of watching the video....
Thanks a lot for taking the time to make these videos about your work! I find them very relaxing after a busy day. Keep up the good work!
/Erik
A second note: you could wind your own springs, music wire is what is used to make them. There is a large range of wire thicknesses available. Match the original OLD spring thickness, hopefully you have the old ones. The music wire is carbon steel and very tough. Make a small winding mandrel and wind a full circle on each end of the springs. Once wound they spring back, so you might have to test wind a few until you get the diameter and length right. Then, you must bake them at 500F for 15 minutes to set the shape. Good to go.
slad roznik Some others have suggested the same thing, but I was able to find another source for some heavier springs. They should be here any day and I will likely tear the machine back down when I finish the job I am on now and put the new ones in.
Great video Keith,I have the same mill with the same problem.Now I know where to look.It might be possible to slip another spring inside the ones you have to increase the compression.
***** I am going to try and replace the springs with evens stronger ones. If it works, I will be more than happy to share with you what I ended up using.
Thanks Keith,I would appreciate any information you come across.I was thinking about it last night and I do believe re-grinding the faces of the ball clutch might be part of the answer as well.It should be doable by just turning up a mandrel in the lathe to hold the clutch body and then cleaning up the face with a toolpost grinder.
Hopefully I can tear into mine this fall,it's just too hot for anything that involved right now.
Enjoyed the video
outsidescrewball Thanks Chuck!
you do love that big taper shank drill :) can't blame you a bit
+Chris Bielanski Indeed!
Great video Keith, thanks again! Could you use your ball mill cutter to make each detent a little deeper maybe - would that help to remove the effect of the wear that is present? Or, could you add shims/spacers behind each spring to increase the tension? I look forward to seeing how you tackle it in any case :)
Your vertical head has gone walkabout :)
You could do a simple spring force test. Compress or stretch the new and old springs with the same mass. Whichever compresses/stretches less is stronger. You could even go as far as to calculate the spring stiffness constant if you want to match the old springs perfectly.
npnpnp Problem is that the four or five original springs that I have left are all slightly longer/shorter than the others. I could get close, but there is still a bit of guessing involved.
Keith, you had TWO flat washers on end of cup .
I think one went on the inside of that cup ?
Powers up tighter tension or lighter tension? Who knows I'm not there. Ask the cat?
two out of three isn't bad Keith !
Lynton Rodda It is a huge improvement over where I started.
Nice edit Kieth ... your spring clip was bent on one side before you tried your successful attempt .. but good idea anyway ,keep up the good work .
hi. great video.
I would like to sugest you source of really strong springs. there are some strong springs in dieselengine injectors.
0:25 *_"...Kearner & Treckey..."_*
A bit of metathesis there! LOL
It might be worth trying to shim the springs with easily made small discs before laying out money for new parts. It would let you know for sure the spring force was the problem. Could turn out to be a permanent fix. Since you have some old original springs you might try and measure the spring force and compare it to your replacements. Great video. I always wondered how these worked.
rfcarlson1 I will probably just try and find some stronger springs.
Just a thought: You said that the original 5/16" ball bearings were replaced with 8mm balls by the previous repairer. 8mm balls will not go into 5/16" holes. Therefore, the gear holes are larger than 5/16". I think someone may have re-machined 8mm holes in the gear which, in combination with the worn ball plate, could be giving the new 5/16" balls too much wiggle room. A possible solution would be to re-machine the ball plate to have 8mm hemisphere impressions, install new 8mm ball bearings and install stiffer springs. You would have to do some scribbles to work out how much torque the new arrangement will slip at.
Just watched this again after thinking about it for a while. I think easiest cure is just some small rivets inserted in one end of springs, or even both ends if needed. "T" shape of rivet will increase pressure upon each spring (but small increase on each spring equals LARGE overall increase). Rivets just need to be short enough not to interfere with ball retraction.
I thought of something similar to suggest and then realized that it wouldn't work unless you shortened the springs. Don't forget that if you put something like that in there, you're also changing things slightly just because of the depth that the ball would go into the inside diameter of the spring. That in itself might be enough of a difference. Remember that the difference made in one spring may not be much but multiply that by 18 and it's a whole other game.
I had similar problems with my old Eliott and had a similar result. The clutch struggles with the massive weight of the knee, such that I wonder if it ever worked at all!!!
Thank you for an interesting look into the inside workings of an iconic piece of equipment.
I am not familiar with the K&T, so this is pure conjecture. It is inconceivable that there is not a counterbalance, either mechanical or hydraulic, to negate the large weight of the table and knee mechanism. Added to that large weight could easily be another 600-800 lbs of workpiece and work-holding tools. The downward force easily overcoming that rather small clutch pack. Before again looking at the clutch pack I would investigate if the machine has a counterbalance mechanism and look for deficiencies there.
Morris Gallo Several others have suggested the same. I know that some of the larger mills use a counterbalance, but I cannot find anything on this machine - either on the machine itself or by searching through the parts diagrams - that would suggest that there is any kind of counterbalance on this particular model.
Keith maybe you can incorporate something into it some kind of shock system or something
@@VintageMachinery Yet again another great vid. Thanks. And yes to Maurice Gallo, I cannot reconcile the force required to trip the clutch when the rapid traverse mechanism is operated in either of the two horizontally directions with the force required to trip the clutch when the rapid traverse mechanism is operated to elevate the table. Yet it seems that the same clutch mechanism protects the rapid traverse mechanism in all three cases. Either a relatively massive force would be required to trip the clutch when the rapid traverse is operating in either of the two horizontal directions, or there is an as yet not discovered counter balancing mechanism compensating for the considerable weight of the table etc. Given the excellent reputation of K & T for design this does not seem a likely design scenario to me. Or have I missed something? From NZ.
Keith Rucker: ps adjusting the spring compressive force or shimming the spring to ball interface does not address the point raised above, good design though it may be.
Seems strange to me that the springs don't have flat ground ends. With unfinished ends such as you have the pressure on the ball will not be normal to the detent plate. With some clearance in the bore (assume it must have since the old 8mm fitted and they were +0.020") the balls may not seat properly as the "tail" of the spring will force it off to one side. Also I would expect that there should be a small bronze or brass washer that sits between spring and ball, otherwise you will have rotating hard steel ball against stationary hard steel spring - not good engineering?
John Vickers I am going to look for some stronger springs that are better suited for this purpose. I went with what I could easily find to start with.
Keith I would take it back apart and add some shims underneath those springs. Not much maybe .30 or so to increase the spring tention.
Mike Falconer I have found some springs that I think are a better match to the
originals that I will probably swap out after I finish this next job on
the mill.
Add a .100 bronze spacer behind the spring to tighten the clutch up. Or totally bypass the clutch, by making a solid part.
Thank you!
Keith, excellent video, I work on k&t's frequently at work, we have six that run day in and day out, albeit ours are #5's and 6's we had a similar issue when raising the knee which is several tons on a machine that size, turns out the knee lock was out of adjustment. The lever mounts on a spline and can be positioned wherever, the lock mechanism itself is a cam which pushes on a brass rod to tighten the gib. Theres a timing which must be just right, ours was slightly "retarded" so that it was loose about mid travel of the lever and when the lever was returned to the "loose position" the cam was actually locking up again. Yours may be different, but it's worth a look. On the larger k&t's the manual crank is gear reduced whereas the rapid drive is direct to the elevating nut itself so while it was easy to crank by hand the rapid didn't stand a chance.
+cgprecision I am pretty sure that the lock is fine as it is clearly loose when you loosen it, but worth taking a closer look at.
Find out what the torque spec should be on that clutch pack and check to see if it is within spec. If it is not, you can try making little cup inserts that slides into the end of the spring that sits on the ball. With some math and Hooke's law you could figure how thick the inserts need to be to bring the clutch into spec.
Just an idea,
Chris
shadowdog500 Yeah, I would love to have that information on the specs. If only I knew where to find them. The guy who told me he would rebuild it to "factory specs" is not willing to part with that information as that is how he makes his living....
I wonder if the Z axis is dragging a little bit? Perhaps some sliding surface cleanup would reduce friction enough where the clutch would hold?
I think it's the plate the bearings sit in (PLUS maybe the wrong springs). You noted that the bearing were metric, essentially the wrong size - bigger, which likely worn or pushed out the top edges of the holes. That, along with your treatment (cleaning out the holes), along with weak springs is what I would focus on. Also, you should build a jig to mount the clutch onto and torque test it out of the mill. You can gauge it from a test of your existing clutch with a torque wrench.
Were the new bearings 8mm or the smaller size...I forget what size you ordered.
I just looked at the vid again and noticed that even with the slipping the table still rises. This tells me that there is likely more than enough force being provided by the springs. If they weren't strong enough I would think the table wouldn't move at all. It's the holes in the plate. Before you make a new one I would buy slightly bigger bearings and try boring the existing holes (big enough that the top edges are crisp), to match the new bearings. This part seems to have a lot of room for different designs that would work.
another thing that can be done is adding some material by welding it in the channel digged up by the bearings and reface the piece on the lathe, then re heat-treat the piece, even if i dont think it would be necessary
Hello Keith I look you video 3 time and that clutch You have look 1 clutch material and is fiat I see one pin is not all way throw but the other 2 are flat with the material so no full contact with the disc you cut those spring ,sorry is wrong maybe you can find good strong spring from auto transmission shop, this clutch it work of all together ,clutch material,spring and ball bearing if the table lock with the head ball bearing loose out stop move I love this machine I have one and rapid dont work at all ,one day I will open it keep ON you are excellent teacher THANK
Hito Ortega I have now found a source for a spring that is stronger and more closely matches the originals. I will likely take this machine back apart after I finish this next job and replace the springs again. Trial and error to find the right strength since I don't have the original specs.
your gib is binding check the retaining screws that adjust it in and out
i hate K&T's my brother loves them lol but that is a great machine size
for squaring stock and if it is in tram will do work for a long time
good luck
5/6th success! Yx2 works, Xx2 works, Zx1 works, only Zx2 doesn't, so not bad all things considered!
At least there was a change..more spring pressure I'd try if it becomes an issue..
ZIGgassedUP Yes, I agree - just have to find a source for stronger springs.....
Keith, it seems to me that even though your clutch works fine for the x and y axis, that lifting the knee is just too much of a load for it. I had a similar problem once with a different type of machine and my solution was to install a pulley/counter-weight system to counter-balance, and take most of the load. It worked great and looked like OEM equipment. You might be able to do something similar for your knee fast traverse until you solve the real problem.
***** Some of the bigger mills have a counter balance built into the knee. This one does not. I have sourced some heavier springs that are more in line with the originals that I plan to put in soon. I hope that will fix the problem once and for all.
Hi Keith I have just been watching the K&T rapid traverse clutch rebuild and noticed the clutch plate appears to be larger than the pressure plate it also appears to be worn this would reduce the friction and maybe the cause of he problem, I hope this may be of use to you Ian from Taunton England
Hi Keith, The springs you are using has been cut from one long spring. Maybe it is the right size but the ends are the wrong shape. The original springs sits flat on the bearing balls. If you don't have the correct springs then one side of the ball will have more pressure than the other side. To fix your problem using the same springs that you have, you need to machine spring ends that part of it fits inside the spring and part of it will be the same diameter of the spring and hollow in the middle. This will push equally on the balls.
HKCNC1 I am going to try and find new springs.....
*No lithium grease to hold/lubricate the ball bearings? (to prevent the clutch material from getting oil/grease on it?) No oil/grease during assembly on the gears inside the housing at all? (i see the oiling on the drive pulley gears toward the end . . . does that deal with all the housing's internal gearing?) What is it that i fail to properly understand about such equipment, Keith?*
As long as the springs are not compressed to the point where they are " solid " , you might be able to install some shims to increase the force / pressure they are exerting ?
Wyr
God bless
Hi Keith
I cringed when I saw the pressing action with the snap ring, my first thought was he needs a tool similar to a steering wheel lock plate remover. It would compress the springs and then you could use snap ring pliers to install the clip. I also agree with "flip de boer" in that the gear should have been all the way down over the balls before it was pressed, something to look out for when you take it back apart. Do you think it would be possible to wind the springs you need yourself with music wire? I enjoyed the video and seeing how it was built, thanks for sharing. John
imystery man That snap ring would not work with snap ring pliers. It is a totally different design.
You could have either sat the ball bearings in a little grease to stop them rolling away or even easier, why not just put the two big parts together first then drop them down the holes in the top part before putting the springs in too on top?
I suppose things always look easier afterwards!
I still enjoyed watching working on something I've never worked on myself before.
David Dale Yeah, sometimes the obvious is not very obvious until you watch what you did on film....
Good work there, Keith.
I'd consider it 2/3rds successful! Because of the rebuilding you did to this point, I think you're on the right track and should continue exploring the spring pressure route. (Will Cali. Sell just the springs?)
dadatschool I have found some springs that I think are a better match to the originals that I will probably swap out after I finish this next job on the mill.
Great video of a difficult project. Thank you for the videos, keep them going please? One question, how is this setup lubricated?
slad roznik The entire inner workings of the mill all runs in a oil bath. About 4 gallons of oil in the case. There is an oil pump that then pipes the oil to the critical areas. There is also a window on the side of the mill that you can look through and see if the oil is pumping when the mill is on - you just see oil splashing against the window and running down.