Torquing your Chuck

P

peter.van.haren

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Anybody/everybody using a torque wrench when mounting their chuck(s)?
Meaning on a "bolted on" chuck like an ASA A1/A2 or other?
Guess it can't hurt, Or is it overkill?
Thx!

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I've been running lathes since 1968 and I have yet to use a torque wrench on one, I would say overkill. If you need that much precision, the job should be finished on a cylindrical grinder, not something that many hobbyists would have.
 
Mini Cooper S said:
I've been running lathes since 1968 and I have yet to use a torque wrench on one, I would say overkill. If you need that much precision, the job should be finished on a cylindrical grinder, not something that many hobbyists would have.
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Thanks for your reply. I did expect it is overkill and the reason I was (am) doing it is because the chuck is mounted to a tapered collar (spindle nose ASA A1-5 in my case) and wasn't sure if possible runout could occur because of seating. Being a new lathe owner, confidence in knowing what/what not to do is still in the making.
Sorry for the noob question. :)
 
I use a torque wrench when assembling a chuck after a service. mounting to a lathe just common sense. In answer to your concerns, yes, incorrect tightening WILL cause uneven seating and runout. How do I know you ask?
I have a D1-5 mount and was careful to seat gently and then work as if I were tightening down a cylinder head then I watched a YouTube where an expert said you can just tighten the screws in one hit so I tried it. A few days later I went to trim something up and couldn't figure out why the work wasn't running true. Took the chuck off to check everything was clean, re-mounted and back to normal.
Just make sure all mating surfaces are spotless and burr and ding free and seat gently then progressively tighten down in 3-4 hits working across/around chuck like you would an ICE cylinder head. That is my experience.
Don't ask, never know.
 
peter.van.haren said:
Thanks for your reply. I did expect it is overkill and the reason I was (am) doing it is because the chuck is mounted to a tapered collar (spindle nose ASA A1-5 in my case) and wasn't sure if possible runout could occur because of seating. Being a new lathe owner, confidence in knowing what/what not to do is still in the making.
Sorry for the noob question. :)
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I understand your concern, I snug the cams tightening opposite cams to pull the chuck in evenly. I will go around all cams about three times to get to full tightness this keeps everything even.
 
Thanks gentlemen. Torquing just gives me the feeling it's done right. 30 ft lbs of feeling. Ha ha ha

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You really should not need to torque a D1 style spindle mount. If it makes you feel better, then fill your boots - however, so long as it is snug and not over tight it should not matter.

If you are finding that the tightening sequence or how tight (on the D1 cams) is making a difference - that is telling you that there are other issues with the mounting of the device to the spindle. The flat of the back of the chuck (or whatever you are mounting) AND the cone of the short taper must both close completely. It is not unheard of for the chuck to not quite close on that flat face - in which case it is very possible that every time you mount the chuck it will be slightly different. The short taper is really only intended to provide radial alignment, it is way to short to ensure axial alignment. When you are setting up a new back plate (or chuck if you have an integral mount), you need to confirm that the back plate mounts properly. One quick check is whether the back plate tends to stick on the spindle - if, after you loosen the cams you also have to smack the chuck with a block of wood (dead blow hammer), then be suspicious that the back plate is not sitting all the way down. If is okay if the chuck sticks a little, but it must close 100% against the flat face of the spindle.

If is is not sitting flat against the spindle, then how you tighten the chuck will very likely make a difference. In which case, deal with the problem instead of some goofy tightening procedure!

If there is a tiny gap after the chuck is mounted on the spindle, then fix it - it is pretty easy, just part of the chuck tuning procedure that has been discussed here on HM previously (likely a few times).
 
BtoVin83 said:
I get mine "oilfield tight" (tight as you can get it and then two more times around)
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OK, now I'm confused. What's tighter - "Oilfield tight" or "Farmer tight"? I've tried looking in various handbooks and can't find any mention of an ANSI standard. Google didn't help, either :)
 
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