Time to get a new chuck mate. A lathe is only as good as the chuck and the man using it. The best way to do this is to drill a hole in the exact same place in the furthest most part of each jaw for a small bolt. Then get a short length small diameter ring held on the very front by the heads of the bolts and tighten well. The smaller diameter you can do this the better. Feed the grinder in and out automatic making sure to clear the pass each time at both ends. If you want to you could even make a couple of spring passes from the back out most of the way but not the very end.
l allready did get a new chuck! I've seen the holes in the jaws since ( useful for holding copper protection in place too!! ) but the bIocks work very well !
Good information as well as learning curve done here as well as VERY good video images. I aspire one day to present my own and hope to share some of my experience with others like yourself so as when I no longer need oxygen then some of what I have learned is not lost! Cheers from John, Australia.
Thank you! I want to get back to my videos, I've got a couple in the planning stage! Thanks again, regards, Matthew.
Před 5 lety+1
If you keep loading one inch stock then the scrolls will wear at that point and every where else will be true. In general usage you use a variety of thicknesses so should wear more evenly.Thank you for showing how to true up the inside face of the jaws.
Yeah ive found that with certain diameter stock the three jaw chuck is more out of wack than at other dimeters. Im guessing thats due to most work being done with stock of roughly that size
Hey man. You need a thing like a tungsten milling bit or square router bit to cut the new face inside the jaws eh. Since that pink shit wears away just so so quickly. It's a good video and I needed to see done what you have done to hone my own ideas of fixing this age old situation. My lathe is an old basket case that is cobbled together out of whats left of a once fine machine with a big thread that takes the chuck. It can make some round things though. There is no substitute for expensive new things. Keep up the good work. I cant get a new lathe either.
Hi Jack, thanks for your comment! Well, that pink stuff is fine, I wasn't taking off a lot of metal! It did the job. I did end up changing the chuck as not only was it bell mouthed, the jaws rocked in their slides and the scroll was past it! It's for demonstration purposes, it's a 1942 chuck that had done a lot of work!
I've seen a number of these videos and it seems fairly common to go into the chuck with some kind of round grinding wheel, or stone. Not only is the way the grind is applied contingent on how parallel the jaws are to the z axis, but you're also grinding them at a radius. for small parts the surface will impact the parts somewhere in the center of the curved grind, but then at some point you'll be contacting at the outer points of the radius. I have no expertise at this at all, but I have to wonder if the best grind would be done on a milling machine and ground 'flat' or on a surface grinder and the jaws be mounted so they are a perfect 90 degrees to the track that the jaws slide on. I believe that if one has slop or play in the jaw tracks that will be another issues that must be addressed, and not simply grind the Jaws with a greater than 90 degree angle which would result from clamping them onto something creating tension before the grind. One problem is that you cannot assume that the slop or angle of the jaw be consistent through it's travel so it's better to address that slop and fix that as well. As a quick fix that will certainly improve a chuck I think that what's done in the video is fine, but to get a more precise repair I have to wonder about other methods short of buying a new chuck. I've noticed that on my chucks the body of the chuck is soft steel, and that the jaws are hardened.
Fred, thank you for your comment, your absolutely right, but I only set out to improve repeatability! As it turned out, my chuck was so badly worn that I replaced it. Chucks very often have curved surfaces on the clamping jaws as it is a good way to make them concentric. I wasn't out to make them perfect, once ground, the point where they were reground is the only diameter that will be repeatable, the rest of the clamping range was improved, but it will never be a new chuck again!
I would reduce the chuck speed by half, push the grinding stone much deeper into the grinder and reduce three quarters of the stone's length by about 0.2 mm in diameter. Happy grinding brother.
Thanks Mate, input is allways welcome! I am amazed at how many people have watched this Video! I originally made this Video to show the technique to a friend! Unfortunately I cannot remember the name of the person who originally posted this method on a Website some 20 years ago!
Hi, okay. But it is true for that particular diameter of the zone were you ground it. once the job diameter changes then you will face the error again. It means the error is depending upon the internal spiral plate not only with the jaws. The damage is not equal at all times. Thank you
Mmm great talk -thru. Old chucks! yes, what to do! almostto the stage of throw away - but from what you've shown, still salvageable- I was ahead of you with the taper runout - WHY NOT use thicker Plates aka Blocks to give square centering of the jaws ? But then again if jaws are wobbly, the almost knife edge of a steel strip would be better than the indeterminate hold of blocks -and would they be truly parallel ? Will have to go out and check for myself - the beauty of all these instructional videos - not so much "who is correct", rather "showing how to overcome a problem" Thanks - highlighted some issues - Learning by Watching from experience
Thanks for your comment, I still haven't made the backplate for the new chuck! I agree, this is more about spreading the idea of being able to regrind a chuck. The original chuck is something like 75years old, it'll probably serve as a welding positioner! Regards Matthew
I'd like to gring the jaws on my little 7x12 lathe chuck but would need to be very careful. Just taking metal off those faces can leave a hole when the jaws are closed for small diameter parts. Wondered if your stone was so soft it was reducing it's diameter as you went in making it tapered.
The ja ws on mythree jaw chuck were badly worn, 75years old, they had had a hard life, probaly in an industrial setting. The stone I used wasn't a soft one, so, the taper came from the jaws rocking. I doubt you will have much wear in your chuck, so you won't need to grind it much. Do you really need to grind it? Don't hold me responsible for any damage! Cheers Matthew
I am assuming that you have got this clearance on the top of the jaw after grinding because the lathe ways is not 100% parallel to the centerline of the spindle, I assume you will get a decent taper if you ever turn a cylinder, I really dont think that clamping down was the cause, in such an operation you MUST check if your lathe is making a taper or not first other than that you will never get a parallel jaws
I'm not sure about the clearance that you are referring to. This nearly eighty year old chuck was bell mouthed and had both worn jaw ways and scroll. I had considerably improved the chuck, but, it wasn't consistent enough for my liking. I have subsequently replaced the chuck with a new 8" 200mm chuck. the alignment of the new chuck is spot on! Despite it being 2" 50mm smaller, I have gained in capacity as I have both inside and outside-jaws! Regards, Matthew.
@@GraphicManInnovations That's due to the wear in the ways the jaws run in, instead of moving in a straight line, the wear has put a curve in the ways. This allows the jaws to rock outwards. I was able to reduce this by putting the blocs in the front. It was better! As I said, a new chuck corrected all that! No misalignment with the bed!
@@MatthewTinker-au-pont-blanc I have ground a chuck using hot glue and it is very secure. Gripping a piece of round stock with the tips takes the play out and puts them in a normal gripping position.
I don't understand the splits. Surely they will put compliance into those pieces, and the jaws will end up in an undefined position. Solid pieces will guarantee that the jaws are exactly where they should be.
I disagree, the slots to the holes provide a slight spring which allows any small differences in the seat of the jaws to be taken up, allowing a more accurate grind! Regards, Matthew
Very nice comparison video. I would never do a chuck grinding youtube video, my skin is not thick enough for the comments.HA . Are you going to do new videos, just subscribed to your channel.
Thanks! Yes I've got more videos planned, the final grind on my surface plate and the final of the Warco mechanical hacksaw! The comment wsre't too bad, interesting to see how other people think! Regards, Matthew
Thank you for taking the trouble to make this video and for sharing some interesting considerations. However, please do set up some decent lighting, edit out auto-focus issues etc, turn off the radio in the background, and if you are having a problem about what you want to say, script it and/or use subtitles.
Thank you for your comment! You might not have noticed the date, I am working on the problems of lighting etc, I now no longer have the radio on when filming. I speak like that naturally, it's not that I don't know what to say! I have no intentions of subtitling my mother tongue!
@@MatthewTinker-au-pont-blanc Thank you. Understood. Almost all the engineering and other video creators use subtitles to supplement the spoken word, irrespective of their mother tongue. Long pauses, ums and ers, repetition etc detract from the message.
@@RicktheRecorder I don't work in the same way as other people, I have ADHD, and dyslexia, writing a script is beyond me, I am approaching things from another angle, trying to learn from seeing myself in action. It takes me a long time to get around to making a video, I prefer posting them, even in their imperfect state than to never post at all! Writing a paragraph is OK, beyond, my concentration goes! I'm oral, cheers, Matthew
Of course but can sometimes improve things! I did end up replacing this one! I was thinking about cutting the jaws off nearly flush and making soft jaws which would compensate for scroll wear!
Thank you for your comment! I see where your coming from, it's not the case, I waited till it stops sparking to know when I've ground the full length. The check is so badly worn that the jaws rock, by moving the blocks out to the end it improved things! The chuck is going to be relegated to a welding turntable as I've replaced it with an 8"/200mm chuck!
Thank you for your comment! The cuts allow a better closing, they compensate for slight differences in the wear on the jaws. The problem is wear, not the cuts! Once reground, the chuck will be accurate at the diameter it was ground at! Cheers, Matthew.
I can't remember, Sunpapa I think, haven't seen a video by him in ages. I remember he chilled the ends of his jaws and used a ring to put closing pressure on the jaws !
Your grinding wheel is tapered and you weren't passing the largest part all the way through to the rear of the jaws. You can see this by the shiny marks on the jaws being tapered.
Thank you for your comment. The stone went through until it sparked out. It doesn't mater if it's conical. The marks on the jaw are tapered because the slides on which the jaws ride are worn allowing them to tilt out. The wear in this 70+ year old chuck meant that it was despite it being much improved I decided to replace it.
Time to get a new chuck mate. A lathe is only as good as the chuck and the man using it. The best way to do this is to drill a hole in the exact same place in the furthest most part of each jaw for a small bolt. Then get a short length small diameter ring held on the very front by the heads of the bolts and tighten well. The smaller diameter you can do this the better. Feed the grinder in and out automatic making sure to clear the pass each time at both ends. If you want to you could even make a couple of spring passes from the back out most of the way but not the very end.
l allready did get a new chuck! I've seen the holes in the jaws since ( useful for holding copper protection in place too!! ) but the bIocks work very well !
Good information as well as learning curve done here as well as VERY good video images.
I aspire one day to present my own and hope to share some of my experience with others like yourself so as when I no longer need oxygen then some of what I have learned is not lost!
Cheers from John, Australia.
Thank you! I want to get back to my videos, I've got a couple in the planning stage! Thanks again, regards, Matthew.
If you keep loading one inch stock then the scrolls will wear at that point and every where else will be true. In general usage you use a variety of thicknesses so should wear more evenly.Thank you for showing how to true up the inside face of the jaws.
Yeah ive found that with certain diameter stock the three jaw chuck is more out of wack than at other dimeters. Im guessing thats due to most work being done with stock of roughly that size
Hey man. You need a thing like a tungsten milling bit or square router bit to cut the new face inside the jaws eh. Since that pink shit wears away just so so quickly. It's a good video and I needed to see done what you have done to hone my own ideas of fixing this age old situation. My lathe is an old basket case that is cobbled together out of whats left of a once fine machine with a big thread that takes the chuck. It can make some round things though. There is no substitute for expensive new things. Keep up the good work. I cant get a new lathe either.
Hi Jack, thanks for your comment! Well, that pink stuff is fine, I wasn't taking off a lot of metal! It did the job. I did end up changing the chuck as not only was it bell mouthed, the jaws rocked in their slides and the scroll was past it! It's for demonstration purposes, it's a 1942 chuck that had done a lot of work!
I've seen a number of these videos and it seems fairly common to go into the chuck with some kind of round grinding wheel, or stone. Not only is the way the grind is applied contingent on how parallel the jaws are to the z axis, but you're also grinding them at a radius. for small parts the surface will impact the parts somewhere in the center of the curved grind, but then at some point you'll be contacting at the outer points of the radius.
I have no expertise at this at all, but I have to wonder if the best grind would be done on a milling machine and ground 'flat' or on a surface grinder and the jaws be mounted so they are a perfect 90 degrees to the track that the jaws slide on. I believe that if one has slop or play in the jaw tracks that will be another issues that must be addressed, and not simply grind the Jaws with a greater than 90 degree angle which would result from clamping them onto something creating tension before the grind. One problem is that you cannot assume that the slop or angle of the jaw be consistent through it's travel so it's better to address that slop and fix that as well.
As a quick fix that will certainly improve a chuck I think that what's done in the video is fine, but to get a more precise repair I have to wonder about other methods short of buying a new chuck.
I've noticed that on my chucks the body of the chuck is soft steel, and that the jaws are hardened.
Fred, thank you for your comment, your absolutely right, but I only set out to improve repeatability! As it turned out, my chuck was so badly worn that I replaced it. Chucks very often have curved surfaces on the clamping jaws as it is a good way to make them concentric. I wasn't out to make them perfect, once ground, the point where they were reground is the only diameter that will be repeatable, the rest of the clamping range was improved, but it will never be a new chuck again!
Nice to see it done properly with the 3 blocks.
Thank you!
I would reduce the chuck speed by half, push the grinding stone much deeper into the grinder and reduce three quarters of the stone's length by about 0.2 mm in diameter. Happy grinding brother.
Thanks Mate, input is allways welcome! I am amazed at how many people have watched this Video! I originally made this Video to show the technique to a friend! Unfortunately I cannot remember the name of the person who originally posted this method on a Website some 20 years ago!
Hi, okay. But it is true for that particular diameter of the zone were you ground it. once the job diameter changes then you will face the error again. It means the error is depending upon the internal spiral plate not only with the jaws. The damage is not equal at all times.
Thank you
Thank for your comment. Exactly right, but it can be an improvement! The scroll wear will always be there, but the jaw bell-mouth wear can be removed!
Mmm great talk -thru. Old chucks! yes, what to do! almostto the stage of throw away - but from what you've shown, still salvageable- I was ahead of you with the taper runout - WHY NOT use thicker Plates aka Blocks to give square centering of the jaws ? But then again if jaws are wobbly, the almost knife edge of a steel strip would be better than the indeterminate hold of blocks -and would they be truly parallel ? Will have to go out and check for myself - the beauty of all these instructional videos - not so much "who is correct", rather "showing how to overcome a problem" Thanks - highlighted some issues - Learning by Watching from experience
Thanks for your comment, I still haven't made the backplate for the new chuck! I agree, this is more about spreading the idea of being able to regrind a chuck. The original chuck is something like 75years old, it'll probably serve as a welding positioner! Regards Matthew
I'd like to gring the jaws on my little 7x12 lathe chuck but would need to be very careful. Just taking metal off those faces can leave a hole when the jaws are closed for small diameter parts. Wondered if your stone was so soft it was reducing it's diameter as you went in making it tapered.
The ja ws on mythree jaw chuck were badly worn, 75years old, they had had a hard life, probaly in an industrial setting. The stone I used wasn't a soft one, so, the taper came from the jaws rocking. I doubt you will have much wear in your chuck, so you won't need to grind it much. Do you really need to grind it? Don't hold me responsible for any damage! Cheers Matthew
@@MatthewTinker-au-pont-blanc Not wear just cheap Chinese chuck. Will not hold a 1/4 inch HSS round true enough as a test for making small parts.
@@gvet47 In that case, I'd use a small diameter stone, runing as fast as you can (a dremel or a die grinder), taking very small cuts. Good luck!
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Thank you!
Great video Matthew. You gave me a few ideas.
Thank you!
I am assuming that you have got this clearance on the top of the jaw after grinding because the lathe ways is not 100% parallel to the centerline of the spindle, I assume you will get a decent taper if you ever turn a cylinder, I really dont think that clamping down was the cause, in such an operation you MUST check if your lathe is making a taper or not first other than that you will never get a parallel jaws
I'm not sure about the clearance that you are referring to. This nearly eighty year old chuck was bell mouthed and had both worn jaw ways and scroll. I had considerably improved the chuck, but, it wasn't consistent enough for my liking. I have subsequently replaced the chuck with a new 8" 200mm chuck. the alignment of the new chuck is spot on! Despite it being 2" 50mm smaller, I have gained in capacity as I have both inside and outside-jaws! Regards, Matthew.
the clearance at 8:50 (not gripping all the way)
@@GraphicManInnovations That's due to the wear in the ways the jaws run in, instead of moving in a straight line, the wear has put a curve in the ways. This allows the jaws to rock outwards. I was able to reduce this by putting the blocs in the front. It was better! As I said, a new chuck corrected all that! No misalignment with the bed!
got your point, thanks for ur reply
Just clamp a piece of plastic round stock at the tips and hot glue the jaws in place. After glue is set remove plastic and grind.
I don't see any advantage over the block system. I can't see hot glue as being solid enough to take the pressure. Regards, Matthew
@@MatthewTinker-au-pont-blanc I have ground a chuck using hot glue and it is very secure. Gripping a piece of round stock with the tips takes the play out and puts them in a normal gripping position.
I don't understand the splits. Surely they will put compliance into those pieces, and the jaws will end up in an undefined position. Solid pieces will guarantee that the jaws are exactly where they should be.
I disagree, the slots to the holes provide a slight spring which allows any small differences in the seat of the jaws to be taken up, allowing a more accurate grind! Regards, Matthew
Very nice comparison video. I would never do a chuck grinding youtube video, my skin is not thick enough for the comments.HA . Are you going to do new videos, just subscribed to your channel.
Thanks! Yes I've got more videos planned, the final grind on my surface plate and the final of the Warco mechanical hacksaw! The comment wsre't too bad, interesting to see how other people think! Regards, Matthew
Nice, but what's this french radio in the background, when you're obviously a native english-speaker ? 8-)
Glad you liked it! Yes, I am am a "native" English speaker, I live in France! Have done for the last 40 years.
Thank you for taking the trouble to make this video and for sharing some interesting considerations. However, please do set up some decent lighting, edit out auto-focus issues etc, turn off the radio in the background, and if you are having a problem about what you want to say, script it and/or use subtitles.
Thank you for your comment! You might not have noticed the date, I am working on the problems of lighting etc, I now no longer have the radio on when filming. I speak like that naturally, it's not that I don't know what to say! I have no intentions of subtitling my mother tongue!
@@MatthewTinker-au-pont-blanc Thank you. Understood. Almost all the engineering and other video creators use subtitles to supplement the spoken word, irrespective of their mother tongue. Long pauses, ums and ers, repetition etc detract from the message.
@@RicktheRecorder I don't work in the same way as other people, I have ADHD, and dyslexia, writing a script is beyond me, I am approaching things from another angle, trying to learn from seeing myself in action. It takes me a long time to get around to making a video, I prefer posting them, even in their imperfect state than to never post at all! Writing a paragraph is OK, beyond, my concentration goes! I'm oral, cheers, Matthew
Nothing will compensate for differences in wear on the scroll
Of course but can sometimes improve things! I did end up replacing this one! I was thinking about cutting the jaws off nearly flush and making soft jaws which would compensate for scroll wear!
Thats better.
@rats arsed ...the way it was before.
@rats arsed lol I was just trying to have bit of fun...thanks for the explanation, however.
The grinding tool just went part way and therefor it ground it self to a taper thus adding to the problem with the chuck jaws.
Thank you for your comment! I see where your coming from, it's not the case, I waited till it stops sparking to know when I've ground the full length. The check is so badly worn that the jaws rock, by moving the blocks out to the end it improved things! The chuck is going to be relegated to a welding turntable as I've replaced it with an 8"/200mm chuck!
I do not think that I would have the cuts in the blocks, I think this may be causing the problem.
Thank you for your comment! The cuts allow a better closing, they compensate for slight differences in the wear on the jaws. The problem is wear, not the cuts! Once reground, the chuck will be accurate at the diameter it was ground at! Cheers, Matthew.
I was searching for the finnish guy video but I haven´t had luck. it is Suppa? son papa?
I can't remember, Sunpapa I think, haven't seen a video by him in ages. I remember he chilled the ends of his jaws and used a ring to put closing pressure on the jaws !
@@MatthewTinker-au-pont-blanc thanks I will keep searching
@@firelandmetal2933 here it is! sunppaa
@@MatthewTinker-au-pont-blanc thanks so much Sir!
@@firelandmetal2933 pleased to be able to help!
Your grinding wheel is tapered and you weren't passing the largest part all the way through to the rear of the jaws.
You can see this by the shiny marks on the jaws being tapered.
Thank you for your comment. The stone went through until it sparked out. It doesn't mater if it's conical. The marks on the jaw are tapered because the slides on which the jaws ride are worn allowing them to tilt out. The wear in this 70+ year old chuck meant that it was despite it being much improved I decided to replace it.
What about water and soap...
What about water and soap?