Author Topic: Balancing chucks?  (Read 5590 times)

Offline 28ten

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Balancing chucks?
« on: August 17, 2009, 05:16:03 AM »
Whilst testing the mini lathe I noticed a lot of vibration being caused by the chuck, this can't do much for the bearings or indeed accuracy.
Does anybody have any recomendations for curing the problem?
If it ain't broke, i'll fix it until it is.

Offline sbwhart

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Re: Balancing chucks?
« Reply #1 on: August 17, 2009, 07:00:34 AM »
Chuck are well balanced when you get them, its probably the mounting that at fault, can you waggle it, does it pull down square on the mounting plate, have you got the jaws in correct, are the bearing lose ?.

Chuck up a length of sturdy bar get hold of the end and try moving it up and down back to front, it shouldn't have much movement if at all.

Hope this helps

Stew
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Offline 28ten

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Re: Balancing chucks?
« Reply #2 on: August 17, 2009, 07:22:22 AM »
The chuck is firmly mounted and the jaws are correct. Maybe I should try it tonight without jaws? See if they are the cause.
If it ain't broke, i'll fix it until it is.

Offline jim

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Re: Balancing chucks?
« Reply #3 on: August 17, 2009, 07:28:39 AM »
have you tried it with out any gears being driven? sounds more like a bearing on its way out??
if i'd thought it through, i'd have never tried it

Offline 28ten

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Re: Balancing chucks?
« Reply #4 on: August 17, 2009, 07:39:08 AM »
The bearings are fine, it's definatly the chuck. I hope it's something obvious I have missed  :D
If it ain't broke, i'll fix it until it is.

bogstandard

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Re: Balancing chucks?
« Reply #5 on: August 17, 2009, 09:04:19 AM »
All you can do, is get say a 1" lump of bluetak and stick on the side of the chuck, then run it. If by moving the lump around the outside of the chuck the vibration starts to get better, then leaving the blob in position, remove half of it, if it gets worse, add some more to the original lump, by trial and error, if it is the chuck, then you should end up with it eventually being balanced.
Then it is a matter of removing metal from the backplate or chuck, diagonally opposite from where the stuck on weight is, equal to the weight of the lump.

I balance critical flywheels and rotors, but that is easy because I can mount them on a free running spindle, where the heavy bit always drops to the bottom. Unfortunately, you can't do that with a chuck.

You could try to rotate the chuck around to the next set of mounting holes, and see if that balances it out.

But other than that I can't suggest any other way of doing it.

Bogs

Offline 28ten

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Re: Balancing chucks?
« Reply #6 on: August 17, 2009, 11:03:20 AM »
I just nipped to the workshop while the kids had their sleep, and I removed the chuck from the mounting plate, and. It would appear that the mounting plate is the culprit. It is a universal mount with several sets of holes that are not evenly spaced, so I need to either drill another hole to balance it, or 'fill' the holes to balance.
At least I have found the problem!
I'm sure the lathe will great when it is sorted but that seems a long way off at the moment  :bang:
If it ain't broke, i'll fix it until it is.

Offline websterz

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Re: Balancing chucks?
« Reply #7 on: August 17, 2009, 11:15:01 AM »
I just nipped to the workshop while the kids had their sleep, and I removed the chuck from the mounting plate, and. It would appear that the mounting plate is the culprit. It is a universal mount with several sets of holes that are not evenly spaced, so I need to either drill another hole to balance it, or 'fill' the holes to balance.
At least I have found the problem!
I'm sure the lathe will great when it is sorted but that seems a long way off at the moment  :bang:

Yup...same problem I had. I made a couple of plugs for mine and pressed them in. No more thumping noises.  :)
"In the 60's, people took acid to make the world weird.  Now the world is weird and people take Prozac to make it normal."
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Offline John Hill

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Re: Balancing chucks?
« Reply #8 on: August 17, 2009, 05:02:48 PM »
If you need to balance a wheel (or chuck I suppose) which has a suitable concentric outer you can roll it on something really smooth, a sheet of glass for example, a few times marking the point that always rests at the bottom.
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