chuck wobble.

[moby]

chuck wobble as per title.

goliath chuck by axminster probably about 0.5mm at slot number 4. its mounted to a luna sp 1000 via an adapter made by a local engineering firm. I removed the adapter, cleaned and oiled the thread, and mounted it back on the lathe. Then cleaned and oiled the male thread that goes into the chuck. Stripped the chuck down to component parts, cleaned them all and reassembled, and then mounted on the adapter.
Still had the wobble. backed the chuck off the shoulder on the adapter, and then used the three allen keys to fine tune the wobble out of the chuck. Got to the point where i needed to give it a bit of a clout with a mallet to get it running true.

Has anyone had a similar experience? would be interested to know what sort of warranty is one the chucks. I've only had it a couple of years.

TIA

 

[CHJ]

• 1. How is the adaptor registered in the chuck, does it use the chucks shoulder register to locate or does it just rely on the thread.
  2. How is the adaptor located on the lathe spindle nose, does it use the register collar or just rely on the thread.
  3. Does the adaptor run true when mounted on the lathe spindle nose.

Not happy that you say you can alter the run-out with Allen screws, there should be no movement possible if adaptor is aligning correctly on location shoulders.

Both the adaptor female socket and the adaptor male nose should use the Register area 2 to locate itself and the chuck with an absolute minimum of clearance, relying on the threads can result in off centre location if thread form is not perfect, something not easy to achieve during manufacture on a normal lathe and requiring the making of bespoke alignment masters, a time consuming and expensive exercise for a one off item.

 

[moby]

thanks for the reply.
1 adapter has screws up tight to the collar, does not rely on the thread.
2 there is a register collar though it might be a tad loose (will check)
3 adapter does seem to run true with my basic test, the only movement i can find is at the back of the chuck.

I noticed a wobble when turning bowls round to finish off bases etc. basically whenever it comes to remounting (jaws lined up etc)
to check it, I moved the rest up to the back of the chuck (lathe stopped of course) turned it by hand until the rest barely touched, moved it by hand until it touched and then completed a revolution by hand. spun the lathe at 750rpm (min on my lathe) for a couple of minutes, stopped it and then looked for the scratches.

There is no distinguishable wobble from 1 to 2 to 3 (on your diagram) on the lathe spindle or where the adapter (female to male)screws on to the thread at 3. the adapter which has a shoulder and a register collar runs true. its only when the chuck is mounted that there is a wobble.

It is a small wobble (0.5mm) but a 750 revs min its noticeable when you multiply that by the thickness of a bowl or the width then it becomes a serious issue.

any help/advice greatly appreciated.