Cant beat the 4 jaw for versatility. Especially in a job shop where most work requires working concentrically with a pre-existing round feature. Each setup is unique and having the ability to dial it in is essential
I can reasonably easily get within .02" TIR by lining up a reference edge on a dog with one of the circles grooved into the faceplate, then I turn my chuck key in fractions of a turn. The biggest asspain is getting things to run true when you can only clamp .375". If the part Im truing up has a machined face Ill just press the toolpost up against that and it usually gets me close. Its a good idea to turn extra reference lines into the chuck face for this purpose.
another benefit of a 4 jaw vs. a 3 jaw is the 4 jaw will grip a workpiece a bit better - especially when trying to hang onto something flimsy ... keeps the work piece from coming out of the chuck 🙂
I don’t mind four jaws. I usually take diameters of chuck minus diameter of stock. Divide that by two and that’s how far your stock should be from the outside edge of the chuck. Even with a decent tape measure it’ll usually put you within .030” total indicator runout.
I only use the 4 jaw. My 3 jaw is 40 thou out. The lathe isn't something I use enough to buy another chuck. I'm getting pretty good though. I'm doing it in about half the time i was when i first used it probably 3 to 4 min dialing in.
My 3 jaw was .030 out. I fixed it by pulling the dogs out, cleaning them out and dragging the grit out of the spiral gear by spinning it with a wire brush in the grooves, and put all the dogs back in the correct order. You can find the right order by looking at where the teeth start on the dog if they dont have matching numbers. Also check the taper inside the chuck to make sure that its free of debris. My 3 jaw now has .004 runout and its a 60 year old pos. There is absolutely no possible way your 3 jaw is hopelessly .040 out, theres something funny there that you can fix.
That chuck you were using, with the other 4 empty slots, could you turn it into a eight jaw chuck ? I don't know why you would ever need to, but if you did, could you.
Those other "T" slots do no have enough casting material to modify for extra jaws, the purpose of the T-slots is to help hold work tight against the chuck. Here is a link to a video on turning brake drums where the jaws, and T-slots are both used together for holding the part: ruclips.net/video/GqV9PYe_NlQ/видео.html
4 jaws apply force against opposing jaws, which is inherently stronger. 3 jaws apply force inbetween opposite jaws which give the part a chance to move. If it matters always use a 4 jaw. CNCs seem to negate this somewhat with more clamping pressure.
The man is a wealth of knowledge
I was told to leave 4 jaw chucks on to keep the engineers off of the lathe.
I like your videos very much. I'm 60 years old and they have inspired me to take some courses at my Community College
That's wonderful to hear. I hope you enjoy picking up some new skills!
Thanks for another video. I could listen to your knowledge and experience all day.
Cant beat the 4 jaw for versatility. Especially in a job shop where most work requires working concentrically with a pre-existing round feature. Each setup is unique and having the ability to dial it in is essential
great stuff Sir, thank you so much.....cheers from Florida, Paul
I can reasonably easily get within .02" TIR by lining up a reference edge on a dog with one of the circles grooved into the faceplate, then I turn my chuck key in fractions of a turn. The biggest asspain is getting things to run true when you can only clamp .375". If the part Im truing up has a machined face Ill just press the toolpost up against that and it usually gets me close. Its a good idea to turn extra reference lines into the chuck face for this purpose.
you should make a video on the tail stock chuck in that big lathe!
We did that a few months ago, here it is:
ruclips.net/user/shortsdlWdlNWvjps
another benefit of a 4 jaw vs. a 3 jaw is the 4 jaw will grip a workpiece a bit better - especially when trying to hang onto something flimsy ... keeps the work piece from coming out of the chuck 🙂
I don’t mind four jaws. I usually take diameters of chuck minus diameter of stock. Divide that by two and that’s how far your stock should be from the outside edge of the chuck. Even with a decent tape measure it’ll usually put you within .030” total indicator runout.
I only use the 4 jaw. My 3 jaw is 40 thou out. The lathe isn't something I use enough to buy another chuck. I'm getting pretty good though. I'm doing it in about half the time i was when i first used it probably 3 to 4 min dialing in.
My 3 jaw was .030 out. I fixed it by pulling the dogs out, cleaning them out and dragging the grit out of the spiral gear by spinning it with a wire brush in the grooves, and put all the dogs back in the correct order. You can find the right order by looking at where the teeth start on the dog if they dont have matching numbers. Also check the taper inside the chuck to make sure that its free of debris. My 3 jaw now has .004 runout and its a 60 year old pos.
There is absolutely no possible way your 3 jaw is hopelessly .040 out, theres something funny there that you can fix.
That six jaw adjustable chuck. Buck Chuck. I think they have about .015" adjustment.
That chuck you were using, with the other 4 empty slots, could you turn it into a eight jaw chuck ? I don't know why you would ever need to, but if you did, could you.
Those are different slots, looks like more for face plate kinda work hold, clamping on the work peice
Those other "T" slots do no have enough casting material to modify for extra jaws, the purpose of the T-slots is to help hold work tight against the chuck. Here is a link to a video on turning brake drums where the jaws, and T-slots are both used together for holding the part: ruclips.net/video/GqV9PYe_NlQ/видео.html
@@HOWEES Thanks, once again you have taught me something.
Does a 4 jaw actually have more holding power than a 3 jaw for heavy work?
given similar size, definitely more holding power.
4 jaws apply force against opposing jaws, which is inherently stronger. 3 jaws apply force inbetween opposite jaws which give the part a chance to move. If it matters always use a 4 jaw.
CNCs seem to negate this somewhat with more clamping pressure.