I didn't see anything ground in the video. Replace the word in the title with turn or machine. For best results use a set of soft jaws or soft jaw attachments and turn them to your diameter even if the scroll is worn uneven the work will run perfectly. 40 years master toolmaker, cheers
Winky - I've watched several RUclips videos on this topic. Yours is the simplest way I have seen. You also got the best result. I think I'll try it on one of my old chucks. Thank you for sharing.
If you have .0015 on a 3 jaw chuck that’s good. I have made up aluminum soft jaws for some 3 jaw work that requires removing parts to work around the problem. One thing I noticed is you took light cuts and had a stiff bar, so that’s why that worked out as well as it did. The plus is your not introducing grinding grit to your lathe
Yeah... I've done the same with the dremel. It took hours and I burned up my Dremel. I think this actually worked better for me and it was certainly much faster.
@@geoffmorgan6059 Just bought another Dumore 44-011 for 400, hardly used Needs a new cord. Valuable tool for any lathe work IMHO. Also there is a guy on Ebay that sells a bracket to convert a die grinder to a tool post grinder .
The idea of gaining accuracy in a warn chuck by doing this trick is thwart. Unless you install a new scroll at the same time it will only be accurate at the diameter you ground it at. At all other diameters it shall still be as inaccurate as hell. Solution is to buy a new chuck...they are not dear...
Actually this can and did make a huge difference but it also depends on your expectations. I've never had a 3-jaw that does not vary a little with diameter. Even a new chuck varies. I do agree, this will not restore a chuck to new condition. Jaws wear independent of the scroll. This chuck was worn mostly at the ends of the jaws (bird mouth) and the error was reduced in half by surfacing the jaws.
I'm surprised the boring bar cut it. I built a grinder attachment for my tool post. covered the ways and just ground the jaws. they are still about .003 out I may could do better but like you said the scroll is likely worn on mine as well.
Carbide will cut fairly hard steel. The jaws are harder than a drill but nothing like HSS or case hardening. In this case it cut very well. I have also used a grinder. It took a LONG time and I learned that my Dremel has a two chuck limit - Ha
@@WinkysWorkshop But you will have more tool deflection with carbide and if the jaws are uneven to start with you will not likely get the deflection or tool pressure even by the time you are finished as a grinder would do. Boring it is certainly better than leaving it alone as you showed but grinding it will give you better results.
@@phillhuddleston9445 I have had exactly the opposite experience. Either method works but the grinder has more deflection and takes much longer. If the boring bar is used correctly (square to the cut) there is almost no deflection. Grinding wheels have three aspects that effect this deflection. First the wheel is round and and the jaw will try to push the wheel away. Second, the bearing in the grinder will always have clearance and third, a tool post grinder usually has a small diameter shaft. Of course the 3rd reason depends on the grinder. You can always tell about how much defection you are getting by making a second cut without a change in cutting depth. If you are removing stock on the second pass the previous pass was deflecting. Repeated passes with either method will result in good results but the grinder will need more passes than the boring bar.
@@WinkysWorkshop The grinder will need more passes but you can let it spark out and you can not do that with a carbide inserted boring bar, if the grinding wheel is dressed right and you have a decent tool post grinder the tool pressure and deflection will be minimal. If you are trying this with a half worn out pneumatic die grinder then you will likely get poor results, either way I'm glad it worked to your satisfaction, it's far better than when you started.
@@phillhuddleston9445 It could be that technically the grinder would be more accurate. Certainly the finish would be a little better. However I was probably within .001" which is good for any 3 jaw, especially when there's a .004 to .005 error throughout the clamping range.
Could you put an out ring on the chuck teeth and OPEN it, putting them under pressure and then do the same. or NO, wrong "dynamic" you want to be squeezing in?
Yes the jaws are VERY hard. I was going to put roll pins in the jaws and clamp on a ring but I could not drill them. This worked fantastic. Yes it was a carbide insert in the boring bar
@@WinkysWorkshop I do like the method; it saved an otherwise barely usable chuck. Thanks for the explanation. Some tough carbide that it did not chip on the interrupted cut. What inserts were used? I could use the same treatment on my SB 9 bell-mouthed chuck. On more accurate stuff I use collets so it does not bother me all that much (yet).
If you have one bar that must run true for a special job try placing paper shims under one or more of the jaws. After a few tries indicating you can usually get the bar true within .002 TIR.
Was that you or were you in the group? I was trying to remember the name when I was making the video. I was going mention this. To be honest I have done this before using a similar method but using aluminum and cutting it with the boring bar was way easier.
@@TheKnacklersWorkshop I need to take notes... I got a list of names from Harold but the the channel names are different. I have a hard time remembering 6 or 8 names but 16 is worse.
The reason why the 1 inch bar was not indicating true and the 7/8 did has to do with the Radius of contact to the work piece is not equal, you bored it to one inch but the deflection of the bar and the hardness of the jaw made the Bore Dia like .990 . The Radial contact, Jaw to bar, is on the outer edge of the cleanup of the Jaw surface which you can hear the evenness when boring. The smaller piece has a smaller Radial contact which is evenly centered on all 3 jaws to the work piece . If you would bore the Jaw 1.010 or larger then the radial contact would be in the center. ** Also the positioning of pressure to hold the jaw in place is best closer to the edge of the jaw then against the chuck.** ------Sorry to get technical but it makes a difference.
You are correct about the radius. However, even after cleanup the flat created at the jaw tips was probably .040". I'd have to do some weird math to know for sure but the difference between the outer contact area and the center is likely only about .001". Lets be realistic, this repair is not a complete fix regardless. .005" to .010" runout would still be a big improvement. I agree with the ideal location (toward the tips) to load the jaws although many have stated that the force needed to be deeper in the chuck.
Good idea ,,, you probably thought of this but watch ebay ,,, it could have been the stars were aligned right or something but I bought a 10 "set tru bison 3 jaw hardly used for $200 US ,, the liquidator didn't know what he had but I could tell from the pics
The problem with this chuck is almost certainly a bent scroll at that 1” diameter. This method modifies the jaws to work with that diameter only. Most chuck manufacturers sell replacement scrolls. This would have been a better approach.
This approach does not fix a chuck but sometimes does improve it. The scroll was not bent although I'm sure it had some wear. The biggest problem was the wear on the jaws at the end (bird mouthed). This drastically improved this wear. The run out changed a by .002 in different diameters but clamping and re-clamping does the same. If I remember right it was within .006" throughout the clamping range which is about 1/2 what it was.
Very random viewer here, did you verify that the nose of the lathe was running true before you mounted the chuck? A lathe that old might have bearing issues that would trump anything you did to the chuck.
when the chuck is worn its better to put your shims at the tip of the jaw's to help pivet the slack in the jaw slots not the scroll . i mite use steel shims. try wrapping 1 rap of paper on your 1" stock take a couple of heavy cuts on your stock ,inspect the paper to see if the marks are even from front to back. i drill a 1/4" hole in the face of the jaws insert pins chuck on a short piece of pipe with the pins, tight then bore or grind the jaws
I think the pins are a great idea but i didn't have a carbide drill. I tried drilling and it was too hard. As for the position of the shims, this chuck is very shallow. The shims were slightly toward the front of the jaws. I think its a little better to have the shims load the jaw evenly. To be certain 90% of the stock I removed was still toward the back of the jaw. I quit cutting when the insert started cutting at the tips of all three jaws.
Well done!, When I went thru the same process on my small bench lathe I used a steel ring around the outside of the jaws first. Then I did your method just in case there is a difference when chucking something o.d. vs i.d. I used my shop made tool post grinder with a 1/4" diamond burr. I work on firearms so I need a little smaller radius. Thanks for the vid!, Gerry
Thanks, I've used a grinder in the past but it was a dremel tool. I had better luck with the boring bar plus my dremel has a 2 chuck limit.... I burned it up. I'm sure a better grinder would have worked well.
You should remove the jaws and hit the beveled sides with an oil stone to knock off any burrs. Bluing the contact face of the jaws will let you see if you have machined the full length of the jaws. Glad it worked for you. I use a tool post grinder.
There is a reason for the aluminum and it needs to be thin as well. As the scroll and jaws wear the spacing between the jaws become uneven. By using thin aluminum it can compress. This allows all three jaws to be under load instead of just the two that make contact first. Certainly it is not a perfect fix but it can make things much better.
some chucks the scroll is bevel cut, these cost a great deal more, they are known as precision chucks, I just mounted a 16 inch on my french mounting, by counterboring the removable back of the chuck, I made it a press fit, wrong thing to do as I cannot tap the chuck into alignment, although I got it within 2 thou on the dia. and zero runout on the face, but the jaws are bad, 25 thou bad although they look ok, so I'll try your way, was there a reason you bored inside to outside
Yes I would love to have a precision chuck. I just bought a ER40 collet chuck which will expand my options however. I probably should have bored toward the headstock but the other direction works almost as well. On this chuck there is only about a 1/2" behind the jaws and I didn't want to run the bar in too far. By boring away from the chuck I was able to use a solid carriage stop.
Mount a precision ground bar in an accurately aligned tailstock and apply a very small amount of grinding paste to it. lightly clamp the jaws down and run at the slowest speed while moving the tailstock in and out. This will true up your jaws perfectly ( or as good as anything within the limits of your average 3 jaw chuck).
Hmmm... I like that idea. I wonder if the bar needs to be harder than the chuck jaws? Heck, you might find a real fine diamond coated bar too. Now you got me thinking!
IME it doesn't need to be hard as the paste does the work so roundness and alignment are the major criteria . It's crucial also to move the bar in and out to create an even surface.
@@johngriffin641 Thanks, I'm fairly happy with my current results but you method will probably be better. I'm sure your method takes a while so a combination of both might also be good.
Great result! I wish that I could think of another way to immobilize the jaws, because I imagine that there must be some equalizing of pressure, some small displacement, by gripping on the sides of the jaws. And while I am wishing, I might as well wish for a tool post grinder, too!
I started to drill the jaws and install a roll pin but then realized that the jaws were hardened. I was going to make the pins clamp on a shorts piece of pipe. The aluminum pieces are still putting 1/3 the pressure outward and 1/3 on each side of the jaws (I think). Also, I used a grinder on jaws two times.... cutting with a boring bar worked way better
Most dowel pins are hardened and ground...you have to go out of your way to screw them...caution some dowels have flats to allow air to escape a hole...don't clamp on the flat.
I tried this method over and over and over to a point where i had to take the jaws to the mill and restore their geometry to a point where i can try again few more times. I dont seem to get any consistency using boring bar possibly because my lathe is smaller chinese junk and results in too much flex. The best i've got was 10 1000's Looking for a better way to do this. Maybe a diamond round in the tool holder ?
I've had mix results myself. Your jaws might be harder then mine were but more likely the wear is different or even the shape of the jaws. The trick is to put the jaws under load as if they are holding work and that's hard to achieve. You might try putting the aluminum plates closer to the tips of the jaws but that's just a guess. It sounds like you have taken a lot of metal off already... maybe not worth taking a chance on.
Thanks for the idea. I used a hardened ring, about 2.5" ID to hold the jaws in tension. Then a boring bar to lightly clean up the jaws. Got the runout to .002" two inches from the chuck. Much better than it was. Thanks again.
Grinding the chuck jaws, (or turning them in the case of soft jaws), is about all you can realistically do to refurbish an old worn chuck. I've found that there's usually some wear between the chuck body and the scroll plate register that allows some inconsistency but sometimes just using the chuck key in a different tightening bevel may show a marginally better result. My first lathe had a 3 jaw Self Centering chuck that was so worn out that I found it less frustrating to use the four jaw independent chuck instead. It was two years before I could afford a new 3 jaw but by that time I'd learned to appreciate the superior holding power and the accuracy of the four jaw. My new three jaw was accurate to better than 0.001" on ground MS or silver steel bar but the old four jaw independent could even better this if it was ever needed. Your use of aluminium spacers to hold the jaws apart when turning is a good idea too. Some turners use a steel ring gripped at the back 1/8" of the jaws. (The step being turned away afterwards)
The only thing I don't like about the ring in the back is where the load is. I think the load needs to be closer to center. One viewer suggested a different method... it sounded interesting. If you see the video next week you'll know it worked. Hehe
I did the same with my Asian lathe, but I used a Dremel type grinder mounted to the tool post, jaws unloaded. It became a little better. now I usually wrap a piece of .010" card stock around the shafting, and it gets it very close. I use the card stock to even out the contact along the axis of the chuck and it is much improved from whence I bagan. Enjoyed the video, especially after watching the chit chat on Harold's channel. Cheers!
So cool... glad you saw the chit chat... that was a first for me. Yeah... I was somewhat concerned about evening the pressure but after I flipped the aluminum pieces I realized the jaws were clamping fairly accurately. I figured the aluminum might compress a little if the pressure was a little different but maybe not... either way it worked great. Maybe even better than I think... I need to check it with good shafting. I actually used a dremel on this chuck and one other a few years ago. It helped but the boring bar worked way better... much faster too. Also... I burned up my dremel. I think they have a two chuck limit! Ha
This is close to making soft jaws , anyway when I do inside I use a ring on the outside to tension ,and a pin for when I do the outside . Beware of the radius it leaves behind thow
When using a ring I get taper on the jaw face, so I start with a ring with out jaws too pull a few thou off the interior jaws. Remove ring reinstall jaws and load the back jaws, then turn too that point.
@@WinkysWorkshop Look on eBay and I'm sure you can grab a size plug somewhere around 1.00. They should be straight as an arrow and it doesn't matter if the OD is perfect. I like your channel.
I tried it a with a dremnel attached to my cross slide, grinding the Jaws it did well but I did have the same issue at first.. a few times and it came much more true..but the scroll seems warn too.. but smart move with the aluminum wedges,, I might try with steel wedges to deal with deformation.. also thinking of cutting the scroll with a cnc to true it up
@@WinkysWorkshop if I can work out the spiral shape,,create the path in cad and do some test runs. it might work..I already do some precision cutting in plastic and wood and aluminum for ribbon microphones I make....but for simply grinding just around the scroll surface just to true it up lightly it might work.. maybe I have to start a service..
@@WinkysWorkshop don't worry...what I have is just hobby stuff..im old school and that's why I love your channel...but I max out what I have as well... im good at hacking out my way through life being smart like you... i just happen to have a cheap hobby cnc system I'm thinking of hacking for the scroll..it's an old Chuck I don't care about so if I screw it up so what..I will learn somthing..I learn a lot from you too so thanks
Those old Logan chucks (I think) were made by Kalamazoo Chuck Co. They were light duty new and the years have been unkind to them. I suspect you have some scroll wear, too. You can confirm this if after you true things the way you did (good work by the way!) by checking different diameters of decent round stock. If what I suspect, each different diameter will exhibit a different TIR- i.e. The chuck will not "repeat". I discovered this with a brand new high dollar Buck-Fokardt Adjust-a-Tru chuck (5" dia.). The chuck could be adjusted for any given diameter within its capacity to less than 0.001", but put in a different size and the chuck had to be retuned. I spoke with Buck about that and their answer was "live with it"!
❤ nice tips we use a high speed grinder (30000 rpm) with 6 mm collet chuck and use a small short piece off pipe and first clamp it in the bottom of the chuck then move the pipe to the front and then grind the back inside i think it is important to clean the chuck spiral screw well before you start👍
If you had bought a new Chinese chuck it probably would have been no better. Even top quality USA standard chucks are only about 0.001" if you want better than you have to buy a Grip Tru or similar at mega Bucks. Cost me $ 1200 for a 5 inch one Grip Tru and I had to make my own backplate. Well done and it looked like the boring bar lived to fight another day. Surprised the carbide did not break with the intermittent cut.
Cheap inserts too! I just took small bites. I have two chinese chucks that are actually slightly better but they are considerably deeper and too much overhang. This chuck works better for small spindle.
Thank you for sharing this method with us, it worked perfectly for resurrecting my 3 jaw with bell mouth. It allowed for a grind of the inside and outer surfaces of the jaws with repeatable precision being the scroll was good.
Easier way..... clamp the bit of stock in the jaws and hot glue the jaws to the chuck body. tap out the bit of stock with a drift and use a toolpost grinder to true the jaws. Chip off the glue and you're good to go. Took my old Bernerd chuck from .012" runout to .001"...... Took half an hour for the whole job....
Mark I may try this on my 3 jaw China chuck. I have been using a .750 dowel pin and on jaw #3 I am out minus -.004. Jaw #1 and jaw #2 are absolute zero.
That is strange. I think in order for this to work well the pressure needs to equalize. You might try cutting a slit part way through with a bandsaw in the aluminum. This will allow the aluminum to compress a little so the pressure is more even.
Much better to drill a small hole on the front of each jaw, insert three little bolts with heads and clamp the heads in on a steel ring about 50mm diameter with a 6-8 wall thickness about 5mm long held at the very front and then lightly grind. This will machine the jaws the way they need to be done by putting max spread on the outer tips of the jaws.
Interesting. I always felt like the outward pressure needed to approximate the jaws clamping the work piece. But you might be right. Worn jaws are usually at the tip. This did help the chuck but it was far from perfect.
Good idea to use aluminum which will deform enough to even out the difference between the jaws. You’d get slightly better results if you clamped the shims out near the face of the jaws.
The reason it didn't work the first time, ...you chucked on the edges of that aluminum, where the radius is, and collapsed it.....this introduced an error in the scroll
This is a less than ideal way to fix the problem but I don't really think there is a good way aside from getting a new chuck. With that being said, I think the aluminum crushing helped eliminate some error although probably not much.
Great idea. Is there a possibility there was a slight variance in the width of the aluminum flat bar which may have shifted the jaws slightly off? Just a thought. Thanks for sharing.
Another person I watched doing this used aluminum that was the full or near the full width of the exposed area of the jaws which would seem to impose a more uniform pressure over the clamping force area of the jaws and I would think result in a more uniform loading of the chuck and jaw gear teeth interface ?
You may be correct although it would be hard to get aluminum clamped inside the bore with a diameter large enough to get a boring bar inside. Most worn chuck (like mine) are what Mr. Pete calls Bird mouthed, meaning wider at the end of the jaw so I felt it was more important to load the jaws near the chuck.
Very nice Mark. The ring/spider has always given me "must be a better way" second thoughts. This way you are on the inside edge of the scroll and tightening in as most chucks are used most if the time. And best if all the jaws are fully cut. Plus you don't have to mask off the bed from the grinding grit! Looking forward to seeing if the other method mentioned works as well. Ron
Some have said the hardened jaws will not cut... it worked well for me. Maybe some jaws are too hard but I do know that mine are hard. a drill will not touch then.
Most cold rolled steel is within .002", most 3 jaws are .015" or more. This is not a perfect way to fix a chuck but the objective is to make it better not perfect. Most 3 jaws vary in error with diameter when they are new.
Hey there, If you look at about 3:24 where you put the wrench on your tool post and give it a yank. The whole thing moved quite a bit. That would affect your cutting tool stability and finished results. Thanks for the vid though.
I've never investigated this completely but you install a different change gear. You have to leave the half nut engaged and reverse the lathe between each pass. It's a bit of a pain. You can cut many matric thread with the standard gears if you simply want threads for a nut. The nut is short enough that the error is not an issue. I assume you are cutting threads for a collet nut? You might want to check them with an SAE thread gauges. You might get lucky.
Tried this method on my 9x37 Chinese lathe and got it within .0015 at 2 inches from the chuck! I'll take that any day! Thanks Winky for the posting and take care!
Ive done that many time, but i did use a grinder in tool post. When you try and cut those somewhat hard jaws, you get to much deflection that follows the runout..
I have a South Bend 9c with a 5" three jaw chuck, I ground it true, but the problem was a stretched scroll, so any other size stock it was off. I was able to buy a made overseas 6" chuck for $140. Sometimes you just got to get out the checkbook and save yourself a lot of grief.
Yeah... I didn't have anything. The next day I found a linear bearing shaft that worked perfect. The total runout was about the same but without all that bouncing around.
@@WinkysWorkshop Oh, yeah! Linear bearing shaft would work very well. 8) BTW... at one point I needed to true one of my chucks but I was pretty sure that the jaws were crazy hard so I built a toolpost grinder that I inserted between the jaws (jaws held open by a steel ring) and ran the chuck at low speed while the grinder ran. Grinder rotation was opposite chuck rotation, and it worked pretty well. Now I'm tempted to see if carbide inserts are hard enough to reasonably scratch the side surface of one of those jaws to see if turning might have worked faster (grinding was VERY slow)...
@@timhofstetter5654 - I have ground chucks in the past. I used a moto-tool which was not ideal but the boring bar worked better. I don't know the hardness of the jaws but a HHS drill won't tough them. When I ground them last time I made a ring maybe 1/8" think with three holes for the jaws to go through and then wasted the center out with a drill and boring bar. Kind of similar to the video. One person commented that they used a 1 inch bar held in the tail stock. They put valve grinding compound on the bar, clamped it in the chuck and let the bar grind the jaws. I tried this but I set up my steady rest on center to support the bar. The bar was long and the tail stock was on the other end of my lathe. It made the jaws worse. I suspect this is do you light clamping force, the jaws move when you clamp hard. I went back in with the boring bar and fixed it again.
@@WinkysWorkshop For just one moment I thought I liked the thought of bar-lapping the jaws... but the jaws do rack a little when they're tightened so as each jaw reaches the top as the chuck rotates, it falls onto the lapping bar and as it reaches the bottom it falls away from the lapping bar again. Then there's the possibility of vibration, jaw "hop" and all that. I think it's best to lock the jaws tight one way or the other to work on them. Lapping would take a long, long time, too; the lapping compound cuts nicely, but we're talking about lapping away ten to twenty thou here - that's a mountain of lapping to do. Even the toolpost grinder I set up (I used a handheld air grinder with an AlOx wheel) was awfully slow. Like HOURS. Next time I'll try boring (after just testing to see how well carbide scratches my jaws). Worst case... I could anneal the jaws, turn them with HSS, then reharden them.
@@timhofstetter5654 I tapped the end of an 18 x 1 inch bar until is was spinning true in the chuck and then carefully setup my steady rest on the end. Then I turned the end of the bar in down to 1/2" so that it would chuck in my drill chuck in the tail stock. Then I slid the steady rest toward the chuck until it was 2 inches from the chuck. Theoretically the rod was dead center in the chuck and with enough grinding all 3 jaws would be making full contact. It's the fact that the clamping force was not high enough to grind the jaws as if they were tight. I should have put a dog on the bar, I had problems holding it in the tail stock. I had the lathe in back gear and it only took maybe 1 or 2 minutes. It happened very fast... it really surprised me. It was 320 grit lapping compound (for valves)
hi wink,i did my chuck a while back,and it worked pretty good,i use a piece of black pipe which i cut into a one inch ring,that i placed n the jaws and tightened the jaws on it,work great....stay safe my friend.
Ya technology changes ,,,, the paper my dad worked at for years went under through mismanagement after it was bought out by Thompson Media . As far as presses catching on fire the pit under the press was a 12 x 60 pit 7 feet deep full of newsprint , grease and ink . Once in a while someone would flick a cigarette into pit and start a fire . I enjoy your videos keep them coming , all the best ED
Watch out for tool deflection, I tried to cut a set of hardened chuck jaws like this and it would always come out tapered. A quick grind and they were much better.
Interesting... I had much better luck with the boring bar. I was cutting on the way out at first but made that last 4 or 5 passes going in. The TCMC insert is fairly sharp so most the cutting was going on the leading edge. And the last 4 or 5 passes no correction was made. Overall I'm pleased although less is always better.
Awesome, thank you! Just a heads up. This procedure gets mixed results. It worked well for me but others have said it didn't help. The way I see it, if a chuck is really in bad shape then it's worth trying.
When I was just starting out as a machinist , I noticed this problem that you are having with your 3 jaw chuck . I asked my employer , who was a 3rd generation machinist , what could be done to remedy the problem , and he told me to " Just get used to it " . I asked "why " He said that as long as I was using a Plain 3 jaw chuck , There would ALWAYS be some amount of runout due to the inherent design of a scroll chuck , the scroll is not machined to perfection that you desire . it is what it is . If you want or need less runout from your chuck , you will have to use a 4 jaw chuck or a Buck chuck or a 6 jaw chuck or a collet . Since I started this path as a machinist , I have operated lathes built in 1900 to to modern CNC . lathes built in 1990 , that is almost 100 years of technological improvement & the plain 3 jaw chuck still has this same flaw .
Everything in life has a risk. It's all calculated. Obviously limiting exposure is a good idea but MEK is useful. Heck... they even put it in finger nail polish remover.
@@WinkysWorkshop MEK is deadly toxic and you should absolutely use gloves when handling it. I recommend isopropyl alcohol which is more benign then re-coat the surface with oil or BoeShield when you are done.
@@GuyMarsdenMakesStuff I've read about MEK. apparently its bad stuff when exposure is high. I try to limit exposure. I do wear glove if I use it for more than a minute or two although so far no gloves hold up very well. Have you ever been around a woman removing fingernail polish. I'm not saying I should me bore careful but their exposure is higher than I ever expose myself to .
@@WinkysWorkshop I hope that I can make me a shop also. Just love to machine things. Making something out of the raw state of metal. Nice work too. Peace
@@victoryfirst2878 Heck yeah... I love it. I've always made things but now that I have more tools only my imagination is the limit... well, maybe that's over stated but it's a good feeling. If I had life to do over I would buy the tools I wanted at a younger age. I put it off for various reasons but when you think about it even a used bridgeport mill is way less than some golf carts and clubs.
Nice work! Thanks for the video. I would be super happy if my 3-jaw chuck was only .002" off. You commented about possible uneven loading of the jaws in that the sacrificial aluminum was only about 1/4" thick. What if you had a 3/4" square aluminum bar? Or even a rectangular piece? I guess one could stack up several pieces and screw them together to get a thicker piece too. I would like to true up the 3-jaw on my 1918 Oliver lathe. It has about a 12" diameter chuck.
You may be right although I had better luck with the boring bar. Of course my grinder was a dremel and very wimpy. They have a two chuck limit also.. ha
@@WinkysWorkshop If it works for you brother, it works. Happy machining. Have you checked the headstock alignment before the chuck boring process? I need to fix my 3 & 4 jaw chucks (Chinese rubbish) and fairly new. I checked and fixed the headstock alignment a week ago - 0.2 mm over 700 mm.
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I didn't see anything ground in the video. Replace the word in the title with turn or machine. For best results use a set of soft jaws or soft jaw attachments and turn them to your diameter even if the scroll is worn uneven the work will run perfectly. 40 years master toolmaker, cheers
Sounds even easiest!
No disrespect intended but this video was about fixing a chuck not replacing it.
Use a 4 jaw and indicate!
Winky - I've watched several RUclips videos on this topic. Yours is the simplest way I have seen. You also got the best result. I think I'll try it on one of my old chucks. Thank you for sharing.
Thanks! I was please with the way it turned out
If you have .0015 on a 3 jaw chuck that’s good. I have made up aluminum soft jaws for some 3 jaw work that requires removing parts to work around the problem. One thing I noticed is you took light cuts and had a stiff bar, so that’s why that worked out as well as it did. The plus is your not introducing grinding grit to your lathe
Very true... I have ground several chucks and this work better. Certainly faster!
I never had good results doing it like that. I switch over to a dremel with a round stone to grind the jaws. Glad it worked out for you.
Yeah... I've done the same with the dremel. It took hours and I burned up my Dremel. I think this actually worked better for me and it was certainly much faster.
Buy a Dumore Tool Post Grinder
@@pwddogman Can't argue but you can purchase three new adjust-a-tru chucks for the cost of a new tool post grinder.
@@geoffmorgan6059 Just bought another Dumore 44-011 for 400, hardly used Needs a new cord. Valuable tool for any lathe work IMHO. Also there is a guy on Ebay that sells a bracket to convert a die grinder to a tool post grinder .
@@pwddogman -Fortunately I have a Dumore Series 55. I have just noticed that the prices are over the top. I think you got a very good deal!
The idea of gaining accuracy in a warn chuck by doing this trick is thwart. Unless you install a new scroll at the same time it will only be accurate at the diameter you ground it at. At all other diameters it shall still be as inaccurate as hell. Solution is to buy a new chuck...they are not dear...
Actually this can and did make a huge difference but it also depends on your expectations. I've never had a 3-jaw that does not vary a little with diameter. Even a new chuck varies. I do agree, this will not restore a chuck to new condition. Jaws wear independent of the scroll. This chuck was worn mostly at the ends of the jaws (bird mouth) and the error was reduced in half by surfacing the jaws.
Two thousandths is about as good as I have seen a 3 jaw chuck. Good job there Winky.
No kidding, I love the .002" Thanks
I'm surprised the boring bar cut it. I built a grinder attachment for my tool post. covered the ways and just ground the jaws. they are still about .003 out I may could do better but like you said the scroll is likely worn on mine as well.
Carbide will cut fairly hard steel. The jaws are harder than a drill but nothing like HSS or case hardening. In this case it cut very well. I have also used a grinder. It took a LONG time and I learned that my Dremel has a two chuck limit - Ha
cool - thanks - I truly appreciate the lesson.
My pleasure! Thanks for watching
This is great stuff! If the scroll is worn, error will vary with diameter. If jaws are too hard to bore, use an air grinder. Keep up the good work!
Thanks for the tips! An air grinder would be good however carbide will cut most hardened jaws i think.
@@WinkysWorkshop But you will have more tool deflection with carbide and if the jaws are uneven to start with you will not likely get the deflection or tool pressure even by the time you are finished as a grinder would do. Boring it is certainly better than leaving it alone as you showed but grinding it will give you better results.
@@phillhuddleston9445 I have had exactly the opposite experience. Either method works but the grinder has more deflection and takes much longer. If the boring bar is used correctly (square to the cut) there is almost no deflection. Grinding wheels have three aspects that effect this deflection. First the wheel is round and and the jaw will try to push the wheel away. Second, the bearing in the grinder will always have clearance and third, a tool post grinder usually has a small diameter shaft. Of course the 3rd reason depends on the grinder. You can always tell about how much defection you are getting by making a second cut without a change in cutting depth. If you are removing stock on the second pass the previous pass was deflecting. Repeated passes with either method will result in good results but the grinder will need more passes than the boring bar.
@@WinkysWorkshop The grinder will need more passes but you can let it spark out and you can not do that with a carbide inserted boring bar, if the grinding wheel is dressed right and you have a decent tool post grinder the tool pressure and deflection will be minimal. If you are trying this with a half worn out pneumatic die grinder then you will likely get poor results, either way I'm glad it worked to your satisfaction, it's far better than when you started.
@@phillhuddleston9445 It could be that technically the grinder would be more accurate. Certainly the finish would be a little better. However I was probably within .001" which is good for any 3 jaw, especially when there's a .004 to .005 error throughout the clamping range.
Could you put an out ring on the chuck teeth and OPEN it, putting them under pressure and then do the same. or NO, wrong "dynamic" you want to be squeezing in?
Exactly. This is not perfect buy it usually improves a worn chuck.
I like the jaw suport idea. Looks like the jaws were not hardened. Was it a carbide tool cutting the jaws?
Yes the jaws are VERY hard. I was going to put roll pins in the jaws and clamp on a ring but I could not drill them. This worked fantastic. Yes it was a carbide insert in the boring bar
@@WinkysWorkshop I do like the method; it saved an otherwise barely usable chuck. Thanks for the explanation. Some tough carbide that it did not chip on the interrupted cut. What inserts were used? I could use the same treatment on my SB 9 bell-mouthed chuck. On more accurate stuff I use collets so it does not bother me all that much (yet).
@@milantrcka121 It's a Chinese TCMT 21.51 insert. The interrupted cut isn't an issue as long as you take small bites.
If you have one bar that must run true for a special job try placing paper shims under one or more of the jaws. After a few tries indicating you can usually get the bar true within .002 TIR.
Yes that works well, I have done this several times.
Aluminum LOL. You Americans make me laugh. Next you will change the spelling of Solder to Sodder. LOL Pissing myself laughing.
Colour it the way you want. I will color it the way I want.
Hello Mark,
I wonder where you got the idea to do it that way - lol...
Take care.
Paul,,
Was that you or were you in the group? I was trying to remember the name when I was making the video. I was going mention this. To be honest I have done this before using a similar method but using aluminum and cutting it with the boring bar was way easier.
@@WinkysWorkshop no not me Mark but I was there on Sunday when it was spoken about...
@@TheKnacklersWorkshop I need to take notes... I got a list of names from Harold but the the channel names are different. I have a hard time remembering 6 or 8 names but 16 is worse.
The reason why the 1 inch bar was not indicating true and the 7/8 did has to do with the Radius of contact to the work piece is not equal, you bored it to one inch but the deflection of the bar and the hardness of the jaw made the Bore Dia like .990 . The Radial contact, Jaw to bar, is on the outer edge of the cleanup of the Jaw surface which you can hear the evenness when boring. The smaller piece has a smaller Radial contact which is evenly centered on all 3 jaws to the work piece . If you would bore the Jaw 1.010 or larger then the radial contact would be in the center.
** Also the positioning of pressure to hold the jaw in place is best closer to the edge of the jaw then against the chuck.** ------Sorry to get technical but it makes a difference.
You are correct about the radius. However, even after cleanup the flat created at the jaw tips was probably .040". I'd have to do some weird math to know for sure but the difference between the outer contact area and the center is likely only about .001". Lets be realistic, this repair is not a complete fix regardless. .005" to .010" runout would still be a big improvement. I agree with the ideal location (toward the tips) to load the jaws although many have stated that the force needed to be deeper in the chuck.
Good idea ,,, you probably thought of this but watch ebay ,,, it could have been the stars were aligned right or something but I bought a 10 "set tru bison 3 jaw hardly used for $200 US ,, the liquidator didn't know what he had but I could tell from the pics
Very cool on the Bison
Wow, that’s almost free compared to a new one. Like the beautiful Monarch lathe that “Always Sunny in the Shop” bought for something like $2,500.
Picked up a 915 with a 3 jaw that's basically trash. Did something similar a couple days ago. Better than nothin!
Yeah... it isn't perfect but it helps!
The problem with this chuck is almost certainly a bent scroll at that 1” diameter. This method modifies the jaws to work with that diameter only.
Most chuck manufacturers sell replacement scrolls. This would have been a better approach.
This approach does not fix a chuck but sometimes does improve it. The scroll was not bent although I'm sure it had some wear. The biggest problem was the wear on the jaws at the end (bird mouthed). This drastically improved this wear. The run out changed a by .002 in different diameters but clamping and re-clamping does the same. If I remember right it was within .006" throughout the clamping range which is about 1/2 what it was.
Very random viewer here, did you verify that the nose of the lathe was running true before you mounted the chuck? A lathe that old might have bearing issues that would trump anything you did to the chuck.
Yes, the bearings are perfect. Welcome to the channel!
when the chuck is worn its better to put your shims at the tip of the jaw's to help pivet the slack
in the jaw slots not the scroll . i mite use steel shims. try wrapping 1 rap of paper on your 1"
stock take a couple of heavy cuts on your stock ,inspect the paper to see if the marks are even from front to back. i drill a 1/4" hole in the face of the jaws insert pins chuck on a short piece of pipe with the pins,
tight then bore or grind the jaws
I think the pins are a great idea but i didn't have a carbide drill. I tried drilling and it was too hard. As for the position of the shims, this chuck is very shallow. The shims were slightly toward the front of the jaws. I think its a little better to have the shims load the jaw evenly. To be certain 90% of the stock I removed was still toward the back of the jaw. I quit cutting when the insert started cutting at the tips of all three jaws.
Easiest way to grind a chuck I ever saw
It seems to work although it's not perfect. It will at least make the chuck better.
Well done!, When I went thru the same process on my small bench lathe I used a steel ring around the outside of the jaws first. Then I did your method just in case there is a difference when chucking something o.d. vs i.d. I used my shop made tool post grinder with a 1/4" diamond burr. I work on firearms so I need a little smaller radius. Thanks for the vid!,
Gerry
Thanks, I've used a grinder in the past but it was a dremel tool. I had better luck with the boring bar plus my dremel has a 2 chuck limit.... I burned it up. I'm sure a better grinder would have worked well.
You should remove the jaws and hit the beveled sides with an oil stone to knock off any burrs. Bluing the contact face of the jaws will let you see if you have machined the full length of the jaws. Glad it worked for you. I use a tool post grinder.
There is no question I hit the full length of the jaw, easy to see. I agree about the tips. Thanks!
I'm surprised you were happy to use aluminium over tool steel or even ground steel.
There is a reason for the aluminum and it needs to be thin as well. As the scroll and jaws wear the spacing between the jaws become uneven. By using thin aluminum it can compress. This allows all three jaws to be under load instead of just the two that make contact first. Certainly it is not a perfect fix but it can make things much better.
Why didn't you use thicker stock that went the entire depth of your jaws so you had a continuous cut, not an interrupted one?
One key to making this work is the spacer being able to deform under pressure.
some chucks the scroll is bevel cut, these cost a great deal more, they are known as precision chucks, I just mounted a 16 inch on my french mounting, by counterboring the removable back of the chuck, I made it a press fit, wrong thing to do as I cannot tap the chuck into alignment, although I got it within 2 thou on the dia. and zero runout on the face, but the jaws are bad, 25 thou bad although they look ok, so I'll try your way, was there a reason you bored inside to outside
Yes I would love to have a precision chuck. I just bought a ER40 collet chuck which will expand my options however. I probably should have bored toward the headstock but the other direction works almost as well. On this chuck there is only about a 1/2" behind the jaws and I didn't want to run the bar in too far. By boring away from the chuck I was able to use a solid carriage stop.
Mount a precision ground bar in an accurately aligned tailstock and apply a very small amount of grinding paste to it. lightly clamp the jaws down and run at the slowest speed while moving the tailstock in and out. This will true up your jaws perfectly ( or as good as anything within the limits of your average 3 jaw chuck).
Hmmm... I like that idea. I wonder if the bar needs to be harder than the chuck jaws? Heck, you might find a real fine diamond coated bar too. Now you got me thinking!
IME it doesn't need to be hard as the paste does the work so roundness and alignment are the major criteria . It's crucial also to move the bar in and out to create an even surface.
@@johngriffin641 If I do a follow up video can I use your name in the video to give you credit for the idea. I like it
@@WinkysWorkshop No problem
@@johngriffin641 Thanks, I'm fairly happy with my current results but you method will probably be better. I'm sure your method takes a while so a combination of both might also be good.
You need to be doing this with a tool post grinder.
I've done both. The boring bar is much faster and in most cases just as accurate.
Great result! I wish that I could think of another way to immobilize the jaws, because I imagine that there must be some equalizing of pressure, some small displacement, by gripping on the sides of the jaws. And while I am wishing, I might as well wish for a tool post grinder, too!
I started to drill the jaws and install a roll pin but then realized that the jaws were hardened. I was going to make the pins clamp on a shorts piece of pipe. The aluminum pieces are still putting 1/3 the pressure outward and 1/3 on each side of the jaws (I think). Also, I used a grinder on jaws two times.... cutting with a boring bar worked way better
There are other ways. Its called a spider
Hello, just used this method on my Colchester bantam chuck.
It worked well, improved 7 thou to less than 2 thou. Thank you.
John.
Excellent!
I acquired a 3/4" dowel pin to check my runout. Any large dowel should be good. It eliminates the stock inaccuracies. Nice job. The Logan lives on!
Ha... Yeah, I didn't want to give up on the chuck. I need to get some dowel pins!
@@WinkysWorkshop Standards are ok but I wouldn't want to mess them up.
Most dowel pins are hardened and ground...you have to go out of your way to screw them...caution some dowels have flats to allow air to escape a hole...don't clamp on the flat.
@@larryrestainer9949 Yes Larry, the flats are used when pressing a dowel into a blind hole, which is not recommended.
@@WinkysWorkshop An End Mill is a good substitute until you get some.
What type of an insert did you use to turn them gels down?
A boring bar but I can't remember the insert number. Any would work really.
I tried this method over and over and over to a point where i had to take the jaws to the mill and restore their geometry to a point where i can try again few more times.
I dont seem to get any consistency using boring bar possibly because my lathe is smaller chinese junk and results in too much flex.
The best i've got was 10 1000's
Looking for a better way to do this. Maybe a diamond round in the tool holder ?
I've had mix results myself. Your jaws might be harder then mine were but more likely the wear is different or even the shape of the jaws. The trick is to put the jaws under load as if they are holding work and that's hard to achieve. You might try putting the aluminum plates closer to the tips of the jaws but that's just a guess. It sounds like you have taken a lot of metal off already... maybe not worth taking a chance on.
I don't like the way you use your hand to brake the chuck.
Yeah... can't defend this procedure. Thanks
Thanks for the idea. I used a hardened ring, about 2.5" ID to hold the jaws in tension. Then a boring bar to lightly clean up the jaws. Got the runout to .002" two inches from the chuck. Much better than it was. Thanks again.
Yeah... lots of different way to do this. Thanks for watching!
Why not use a 1 inch end mill shank? Hardened and ground.
a boring bar is cutting in a very small area. A mill would have too much surface area.
It does rely on the jaw chamfers being identical. Not sure how to check that though.
Actually the aluminum compresses and evens out the load. Maybe not totally but it helps.
@@WinkysWorkshop That's true enough
Saving time in machining is very important specialy when you have a lots of projects! Thanks
Very true! Thanks
Grinding the chuck jaws, (or turning them in the case of soft jaws), is about all you can realistically do to refurbish an old worn chuck. I've found that there's usually some wear between the chuck body and the scroll plate register that allows some inconsistency but sometimes just using the chuck key in a different tightening bevel may show a marginally better result.
My first lathe had a 3 jaw Self Centering chuck that was so worn out that I found it less frustrating to use the four jaw independent chuck instead. It was two years before I could afford a new 3 jaw but by that time I'd learned to appreciate the superior holding power and the accuracy of the four jaw. My new three jaw was accurate to better than 0.001" on ground MS or silver steel bar but the old four jaw independent could even better this if it was ever needed.
Your use of aluminium spacers to hold the jaws apart when turning is a good idea too. Some turners use a steel ring gripped at the back 1/8" of the jaws. (The step being turned away afterwards)
The only thing I don't like about the ring in the back is where the load is. I think the load needs to be closer to center. One viewer suggested a different method... it sounded interesting. If you see the video next week you'll know it worked. Hehe
Mark can you do this on hardened Jaws?
So some degree my jaws were hard. I'd say it depends on the degree of hardness. You'll just have to try and see if it works.
I'd be impressed if you get 2 000 one foot away from the chuck.
Me too, it's better not perfect.
Looks like it defiantly helped. Good Job!
Yeah I was pleased with the results! Thanks
I did the same with my Asian lathe, but I used a Dremel type grinder mounted to the tool post, jaws unloaded. It became a little better. now I usually wrap a piece of .010" card stock around the shafting, and it gets it very close. I use the card stock to even out the contact along the axis of the chuck and it is much improved from whence I bagan. Enjoyed the video, especially after watching the chit chat on Harold's channel. Cheers!
So cool... glad you saw the chit chat... that was a first for me. Yeah... I was somewhat concerned about evening the pressure but after I flipped the aluminum pieces I realized the jaws were clamping fairly accurately. I figured the aluminum might compress a little if the pressure was a little different but maybe not... either way it worked great. Maybe even better than I think... I need to check it with good shafting. I actually used a dremel on this chuck and one other a few years ago. It helped but the boring bar worked way better... much faster too. Also... I burned up my dremel. I think they have a two chuck limit! Ha
Looks like a great success !
It's something I've never looked at on my lathe - or any lathe!
Thanks 👍 Yeah... this chuck had a lot of runout
This is close to making soft jaws , anyway when I do inside I use a ring on the outside to tension ,and a pin for when I do the outside . Beware of the radius it leaves behind thow
I think you get better results if the jaws are loaded inward when you grind of cut the ID of the jaws
When using a ring I get taper on the jaw face, so I start with a ring with out jaws too pull a few thou off the interior jaws. Remove ring reinstall jaws and load the back jaws, then turn too that point.
After looking again that doesn't appear to have flippable jaws so that wouldn't work.
If you have a decent "V" block it might be helpful to verify the runout of your "test piece" to make sure that it's not out of round.
I'll find a dowel pin somewhere
@@WinkysWorkshop Look on eBay and I'm sure you can grab a size plug somewhere around 1.00. They should be straight as an arrow and it doesn't matter if the OD is perfect. I like your channel.
@@BELCAN57 Thanks, Somebody suggested a wrist pin. I'll get one from a friend of mine
I tried it a with a dremnel attached to my cross slide, grinding the Jaws it did well but I did have the same issue at first.. a few times and it came much more true..but the scroll seems warn too.. but smart move with the aluminum wedges,, I might try with steel wedges to deal with deformation.. also thinking of cutting the scroll with a cnc to true it up
Wow... cutting the scroll would be a challenge.
@@WinkysWorkshop if I can work out the spiral shape,,create the path in cad and do some test runs. it might work..I already do some precision cutting in plastic and wood and aluminum for ribbon microphones I make....but for simply grinding just around the scroll surface just to true it up lightly it might work..
maybe I have to start a service..
@@chuckthebull I'm 99% manual machines. I do little cad but no CNC
@@WinkysWorkshop don't worry...what I have is just hobby stuff..im old school and that's why I love your channel...but I max out what I have as well... im good at hacking out my way through life being smart like you... i just happen to have a cheap hobby cnc system I'm thinking of hacking for the scroll..it's an old Chuck I don't care about so if I screw it up so what..I will learn somthing..I learn a lot from you too so thanks
Those old Logan chucks (I think) were made by Kalamazoo Chuck Co. They were light duty new and the years have been unkind to them. I suspect you have some scroll wear, too. You can confirm this if after you true things the way you did (good work by the way!) by checking different diameters of decent round stock. If what I suspect, each different diameter will exhibit a different TIR- i.e. The chuck will not "repeat". I discovered this with a brand new high dollar Buck-Fokardt Adjust-a-Tru chuck (5" dia.). The chuck could be adjusted for any given diameter within its capacity to less than 0.001", but put in a different size and the chuck had to be retuned. I spoke with Buck about that and their answer was "live with it"!
❤ nice tips we use a high speed grinder (30000 rpm) with 6 mm collet chuck and use a small short piece off pipe and first clamp it in the bottom of the chuck then move the pipe to the front and then grind the back inside i think it is important to clean the chuck spiral screw well before you start👍
That would probably work very well.
If you had bought a new Chinese chuck it probably would have been no better. Even top quality USA standard chucks are only about 0.001" if you want better than you have to buy a Grip Tru or similar at mega Bucks. Cost me $ 1200 for a 5 inch one Grip Tru and I had to make my own backplate. Well done and it looked like the boring bar lived to fight another day. Surprised the carbide did not break with the intermittent cut.
Cheap inserts too! I just took small bites. I have two chinese chucks that are actually slightly better but they are considerably deeper and too much overhang. This chuck works better for small spindle.
Thank you for sharing this method with us, it worked perfectly for resurrecting my 3 jaw with bell mouth. It allowed for a grind of the inside and outer surfaces of the jaws with repeatable precision being the scroll was good.
Thats great, its not a perfect fix but it certainly helps
my HF 9x20 came from the (tractor/kitchenware/baby formula) factory in Guangdong province with .004 runout on the chuck (not the jaws)
Yeah... I'm please with the way this chuck did
Easier way..... clamp the bit of stock in the jaws and hot glue the jaws to the chuck body. tap out the bit of stock with a drift and use a toolpost grinder to true the jaws. Chip off the glue and you're good to go. Took my old Bernerd chuck from .012" runout to .001"...... Took half an hour for the whole job....
Cool idea. Thanks.
Mark I may try this on my 3 jaw China chuck. I have been using a .750 dowel pin and on jaw #3 I am out minus -.004. Jaw #1 and jaw #2 are absolute zero.
That is strange. I think in order for this to work well the pressure needs to equalize. You might try cutting a slit part way through with a bandsaw in the aluminum. This will allow the aluminum to compress a little so the pressure is more even.
Much better to drill a small hole on the front of each jaw, insert three little bolts with heads and clamp the heads in on a steel ring about 50mm diameter with a 6-8 wall thickness about 5mm long held at the very front and then lightly grind. This will machine the jaws the way they need to be done by putting max spread on the outer tips of the jaws.
Interesting. I always felt like the outward pressure needed to approximate the jaws clamping the work piece. But you might be right. Worn jaws are usually at the tip. This did help the chuck but it was far from perfect.
What kind of insert geometry worked well for you?
It was a TCMT 21.51 insert.
@@WinkysWorkshop Thanks Wink
@@dizzolve You're welcome, thank you for watching!
Good idea to use aluminum which will deform enough to even out the difference between the jaws. You’d
get slightly better results if you clamped the shims out near the face of the jaws.
You may be right about that.
The reason it didn't work the first time, ...you chucked on the edges of that aluminum, where the radius is, and collapsed it.....this introduced an error in the scroll
This is a less than ideal way to fix the problem but I don't really think there is a good way aside from getting a new chuck. With that being said, I think the aluminum crushing helped eliminate some error although probably not much.
Great idea. Is there a possibility there was a slight variance in the width of the aluminum flat bar which may have shifted the jaws slightly off? Just a thought.
Thanks for sharing.
This is very true. although the aluminum is thin enough to average out a little. It's not prefect but I don't think there is a perfect method.
I have the same chuck on my logan 825. I may try to get this done as well. Simple enough.
Let me know how it works for you.
Another person I watched doing this used aluminum that was the full or near the full width of the exposed area of the jaws which would seem to impose a more uniform pressure over the clamping force area of the jaws and I would think result in a more uniform loading of the chuck and jaw gear teeth interface ?
You may be correct although it would be hard to get aluminum clamped inside the bore with a diameter large enough to get a boring bar inside. Most worn chuck (like mine) are what Mr. Pete calls Bird mouthed, meaning wider at the end of the jaw so I felt it was more important to load the jaws near the chuck.
Very nice Mark. The ring/spider has always given me "must be a better way" second thoughts. This way you are on the inside edge of the scroll and tightening in as most chucks are used most if the time. And best if all the jaws are fully cut. Plus you don't have to mask off the bed from the grinding grit! Looking forward to seeing if the other method mentioned works as well.
Ron
"of all"
Some have said the hardened jaws will not cut... it worked well for me. Maybe some jaws are too hard but I do know that mine are hard. a drill will not touch then.
Would it help if you turned your test bar first so you are working with a round part? Good video.
Most cold rolled steel is within .002", most 3 jaws are .015" or more. This is not a perfect way to fix a chuck but the objective is to make it better not perfect. Most 3 jaws vary in error with diameter when they are new.
Hey there, If you look at about 3:24 where you put the wrench on your tool post and give it a yank. The whole thing moved quite a bit. That would affect your cutting tool stability and finished results. Thanks for the vid though.
Wow... you are looking hard. You might also notice that before I started cutting I went in and then back out which removed the backlash you saw.
Enjoyed your video , you gave me some valuable insights thanks!
Glad to hear it!
really enjoyed the way that worked out to fix jaws. I have seen some people use a stone, butt really screwed up the jaws.
Cutting seems to work better for me.
You are so far ahead of me that I’m surprised that you don’t have a piece of ground drill rod for taking those measurements.
That would be better although no 3-jaw is super accurate throughout it's clamping range so cold rolled is good enough.
Sometimes you just got to try something, that's the way most things are achieved.
Agree. It's not a perfect fix but usually improves a worn chuck.
Hey, just as a question, how i can turn metric threads on that lathe? I'm thinking about making a Collet chuck.
I've never investigated this completely but you install a different change gear. You have to leave the half nut engaged and reverse the lathe between each pass. It's a bit of a pain. You can cut many matric thread with the standard gears if you simply want threads for a nut. The nut is short enough that the error is not an issue. I assume you are cutting threads for a collet nut? You might want to check them with an SAE thread gauges. You might get lucky.
@@WinkysWorkshop alright, thx
@@WinkysWorkshop also, dp u know if the spindle has a Morse taper?
@@Lucas_sGarage Yes, its a MT-3 I believe.
@@WinkysWorkshop thx
Tried this method on my 9x37 Chinese lathe and got it within .0015 at 2 inches from the chuck! I'll take that any day! Thanks Winky for the posting and take care!
Yeah, not too bad. You're welcome!
Ive done that many time, but i did use a grinder in tool post.
When you try and cut those somewhat hard jaws, you get to much deflection that follows the runout..
That sound logical but honestly this worked better than grinding for me.
I have a South Bend 9c with a 5" three jaw chuck, I ground it true, but the problem was a stretched scroll, so any other size stock it was off. I was able to buy a made overseas 6" chuck for $140. Sometimes you just got to get out the checkbook and save yourself a lot of grief.
I have a couple chinese chucks One is excellent, one is good and the other two not so good. Oddly the best one was only $89.
Hi Winky, what size Vice do you use in your RF-30 Mill?
I think i't a 6 inch.
Nice idea,what was the cutting tool,HSS or carbide ?
For sure carbide.
who is this guy??
Winky
It's best to use a 4-jaw. 3 jaw chucks will always decentre.
True, if I need dead center I always use the four jaw. Thanks
Thanks for your idea all❤👌👍👏🤝
Welcome 😊
But the chuck jaws look hard to me. A wonder how you can machine it!
They are hard but carbide does well. Maybe some chucks are harder. I know the jaws in this chuck can not be drilled with a standard HHS bit
Always test with fresh drill rod or HSS rod that's been ground to 0.0001" accuracy and is guaranteed straight to some ridiculous tolerance.
Yeah... I didn't have anything. The next day I found a linear bearing shaft that worked perfect. The total runout was about the same but without all that bouncing around.
@@WinkysWorkshop Oh, yeah! Linear bearing shaft would work very well. 8)
BTW... at one point I needed to true one of my chucks but I was pretty sure that the jaws were crazy hard so I built a toolpost grinder that I inserted between the jaws (jaws held open by a steel ring) and ran the chuck at low speed while the grinder ran. Grinder rotation was opposite chuck rotation, and it worked pretty well. Now I'm tempted to see if carbide inserts are hard enough to reasonably scratch the side surface of one of those jaws to see if turning might have worked faster (grinding was VERY slow)...
@@timhofstetter5654 - I have ground chucks in the past. I used a moto-tool which was not ideal but the boring bar worked better. I don't know the hardness of the jaws but a HHS drill won't tough them. When I ground them last time I made a ring maybe 1/8" think with three holes for the jaws to go through and then wasted the center out with a drill and boring bar. Kind of similar to the video. One person commented that they used a 1 inch bar held in the tail stock. They put valve grinding compound on the bar, clamped it in the chuck and let the bar grind the jaws. I tried this but I set up my steady rest on center to support the bar. The bar was long and the tail stock was on the other end of my lathe. It made the jaws worse. I suspect this is do you light clamping force, the jaws move when you clamp hard. I went back in with the boring bar and fixed it again.
@@WinkysWorkshop For just one moment I thought I liked the thought of bar-lapping the jaws... but the jaws do rack a little when they're tightened so as each jaw reaches the top as the chuck rotates, it falls onto the lapping bar and as it reaches the bottom it falls away from the lapping bar again. Then there's the possibility of vibration, jaw "hop" and all that. I think it's best to lock the jaws tight one way or the other to work on them.
Lapping would take a long, long time, too; the lapping compound cuts nicely, but we're talking about lapping away ten to twenty thou here - that's a mountain of lapping to do. Even the toolpost grinder I set up (I used a handheld air grinder with an AlOx wheel) was awfully slow. Like HOURS. Next time I'll try boring (after just testing to see how well carbide scratches my jaws).
Worst case... I could anneal the jaws, turn them with HSS, then reharden them.
@@timhofstetter5654 I tapped the end of an 18 x 1 inch bar until is was spinning true in the chuck and then carefully setup my steady rest on the end. Then I turned the end of the bar in down to 1/2" so that it would chuck in my drill chuck in the tail stock. Then I slid the steady rest toward the chuck until it was 2 inches from the chuck. Theoretically the rod was dead center in the chuck and with enough grinding all 3 jaws would be making full contact. It's the fact that the clamping force was not high enough to grind the jaws as if they were tight. I should have put a dog on the bar, I had problems holding it in the tail stock. I had the lathe in back gear and it only took maybe 1 or 2 minutes. It happened very fast... it really surprised me. It was 320 grit lapping compound (for valves)
hi wink,i did my chuck a while back,and it worked pretty good,i use a piece of black pipe which i cut into a one inch ring,that i placed n the jaws and tightened the jaws on it,work great....stay safe my friend.
Hello Ray, that's great! One viewer offered an alternative method that might take this to the next level, we'll see. Watch fo an upcoming video.
Ya technology changes ,,,, the paper my dad worked at for years went under through mismanagement after it was bought out by Thompson Media . As far as presses catching on fire the pit under the press was a 12 x 60 pit 7 feet deep full of newsprint , grease and ink . Once in a while someone would flick a cigarette into pit and start a fire . I enjoy your videos keep them coming , all the best ED
Thanks Ed!
I have done this a few times.Use steel or brass stops aluminum is to soft.
It's soft but I had the chuck plenty tight and it never crushed the aluminum.
What a great idea.. id have never thought of it either... Lol.
Its not perfect but it works fairly well.
Watch out for tool deflection, I tried to cut a set of hardened chuck jaws like this and it would always come out tapered. A quick grind and they were much better.
Interesting... I had much better luck with the boring bar. I was cutting on the way out at first but made that last 4 or 5 passes going in. The TCMC insert is fairly sharp so most the cutting was going on the leading edge. And the last 4 or 5 passes no correction was made. Overall I'm pleased although less is always better.
Smart, how is the runout on other diameters after turning the jaws?
I testes 1/2", 3/4" 1" 1-2/4" and they were all under .0025. I guess my scroll is still in good shape.
I've enjoyed a number of your videos but this one made a subscriber of me. Thank you.
Awesome, thank you! Just a heads up. This procedure gets mixed results. It worked well for me but others have said it didn't help. The way I see it, if a chuck is really in bad shape then it's worth trying.
When I was just starting out as a machinist , I noticed this problem that you are having with your 3 jaw chuck . I asked my employer , who was a 3rd generation machinist , what could be done to remedy the problem , and he told me to " Just get used to it " . I asked "why " He said that as long as I was using a Plain 3 jaw chuck , There would ALWAYS be some amount of runout due to the inherent design of a scroll chuck , the scroll is not machined to perfection that you desire . it is what it is . If you want or need less runout from your chuck , you will have to use a 4 jaw chuck or a Buck chuck or a 6 jaw chuck or a collet . Since I started this path as a machinist , I have operated lathes built in 1900 to to modern CNC . lathes built in 1990 , that is almost 100 years of technological improvement & the plain 3 jaw chuck still has this same flaw .
Yep, and I can live with .002 but .015" was too much. Someday I'll get some collets.
some chucks the scroll is bevel cut, these cost a great deal more, they are known as precision chucks
wasn't Better to use small grinding stone
I've done it both ways and to be honest this worked way better!
Nice work.
Great idea.
Thank you, EM.
Any time! Apparently this is somewhat hit and miss. Several have commented that it didn't work well for them.
Thanks for sharing the ideas. Love your videos.
Glad you like them! And your welcome
Good
Thanks
Please don’t use MEK !!
Everything in life has a risk. It's all calculated. Obviously limiting exposure is a good idea but MEK is useful. Heck... they even put it in finger nail polish remover.
@@WinkysWorkshop MEK is deadly toxic and you should absolutely use gloves when handling it. I recommend isopropyl alcohol which is more benign then re-coat the surface with oil or BoeShield when you are done.
@@GuyMarsdenMakesStuff I've read about MEK. apparently its bad stuff when exposure is high. I try to limit exposure. I do wear glove if I use it for more than a minute or two although so far no gloves hold up very well. Have you ever been around a woman removing fingernail polish. I'm not saying I should me bore careful but their exposure is higher than I ever expose myself to .
A real nice lathe fella. Good day too.
That's nice of you to say, thanks!
@@WinkysWorkshop So nice of you to show a simple way of straightening out the three jaw chuck for us all on RUclips.
@@victoryfirst2878 I love making the videos now that I am retired. Plus I'm improving my shop at the same time.
@@WinkysWorkshop I hope that I can make me a shop also. Just love to machine things. Making something out of the raw state of metal. Nice work too. Peace
@@victoryfirst2878 Heck yeah... I love it. I've always made things but now that I have more tools only my imagination is the limit... well, maybe that's over stated but it's a good feeling. If I had life to do over I would buy the tools I wanted at a younger age. I put it off for various reasons but when you think about it even a used bridgeport mill is way less than some golf carts and clubs.
shouldn't you have used a ground bar ?
Without a doubt. I found a 3/4" bar after making the video and it was less than .0025
Nice work! Thanks for the video. I would be super happy if my 3-jaw chuck was only .002" off. You commented about possible uneven loading of the jaws in that the sacrificial aluminum was only about 1/4" thick. What if you had a 3/4" square aluminum bar? Or even a rectangular piece? I guess one could stack up several pieces and screw them together to get a thicker piece too. I would like to true up the 3-jaw on my 1918 Oliver lathe. It has about a 12" diameter chuck.
I used 1/8" thick aluminum. On edge it is very strong. You might want to go with 1/4" on the larger chuck.
For a perfect job grinding is the best
You may be right although I had better luck with the boring bar. Of course my grinder was a dremel and very wimpy. They have a two chuck limit also.. ha
hi Mark,nice video,thanks for sharing
Glad you enjoyed it Thanks
Great Tip, Mine is at .018 so that will have to help.
Glad it helped
Those jaws can't be very hard if you can cut it with a boring bar.
The boring bar had a carbide insert. The jaws are hard, a standard HSS drill won't touch them but the carbide did well.
@@WinkysWorkshop Morning Brother, maybe a grinding operation would give a smoother surface?
@@pieterbotes8938 The finish was actually good. I have ground chucks twice before but the boring bar seemed to work better.
@@WinkysWorkshop If it works for you brother, it works. Happy machining. Have you checked the headstock alignment before the chuck boring process? I need to fix my 3 & 4 jaw chucks (Chinese rubbish) and fairly new. I checked and fixed the headstock alignment a week ago - 0.2 mm over 700 mm.
@@pieterbotes8938 As far as I know the head stock can not be aligned. I have lined up my tail stock.
Can't argue with the results. Big improvement.
Yes i was pleased. Thanks
😂
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