Performance CCL tailstock lock

[ThornOfCamorr]

Good morning,
I finally managed to get a closer look at an Axminster Performance CCL I bought used a couple of weeks back. While trying it out, i noticed that the tailstock quill was rotating.

The quill has a groove which should stop it from turning. But the barrel itself does not have anything which locks into that groove (apologies, not sure how to describe it better). The tailstock lock is simply a screw. So nothing is engaging with this groove. Tightening the tailstock lock just means the screw presses against the quill, stopping it from rotating but it also won't slide in the barrel any more.

Doing some research, I found replacement tailstock locks on the axminster website, where the screw has a nose on the end which I assume would then slide into that groove. (Link: https://www.axminstertools.com/axminster-tailstock-locking-handle-600419). I'm wondering if my tailstock lock should have such a nose as well...

Would anyone who owns that lathe or has experience with it be able to shed some light on this?

Thank you

 

[Jamesc]

I don't have this lathe, but it is common practice on many lathes for the lock to have a 'Nose' which engages with the slot in the barrel.
Check that the barrel is aligned with the screw and make sure it is not wound out too far. On my lathes a half turn is all that is need to lock/unlock the barrel. If the 'nose' is missing then the replacement part is cheap enough and should solve the problem.

 

[ChaiLatte]

The tailstock lock is simply a screw. So nothing is engaging with this groove.

Where is the lock in relation to the horizontal centreline of the barrel?

If you remove the lock and shine a torch into the hole, do you see the groove in the barrel?

The locking screw would probably require what is called a 'dog point' so it provides rotational alignment when loosened slightly (1/4 turn) but presses sideways against the barrel when tightened.

If you look at the one to which you link, you see the dog point at the end of it.

Remove the screw and the barrel and see if the point on the screw you have fits the groove in the barrel. It may have mushroomed through abuse. That is easilty fixed.

 

[ThornOfCamorr]

Thx for the input!

If you remove the lock and shine a torch into the hole, do you see the groove in the barrel?

Yes, those align.

I'm confident now that the locking screw is missing the 'dog point'. The screw is a M10, 18mm long. Sounds like the Axminster replacement part will fit, so will order that one.

Thank you again

 

[ChaiLatte]

I'm confident now that the locking screw is missing the 'dog point'.

Have a look at the end of the one you have. Does it look as if the dog point may once have been there?

It is possible that it has been sheared off. You could envisage using a large auger or forstner bit in the tailstock and either a tough piece of wood or a snag. That dog point is the only thing resisting the rotational force of the drill bit so could be the weak link.

It could also happen if someone winds in the tailstock too rapidly or enthusiastically. The barrel would bottom out on the screw and then if force (momentum) remains on or from the handwheel, the dog point would feel it and may throw in the towel.

See what conclusion you come to and if it looks at all dodgy, consider supplementary ways to make your tailstock resist torque loads when the operation being performed demands this ability.

 

[ThornOfCamorr]

Have a look at the end of the one you have. Does it look as if the dog point may once have been there?

Hard to tell, honestly - it doesn't look like the surface I'd expect from a new screw, but that can mean many things... could just be worn from requiring to do a job it was not designed for.



Here some more pics from the rest of the tailstock parts:

 

[Amplidyne]

Looks like the keyway has had some hard use, which makes me wonder if the end of the bolt that acts as a key hasn't snapped off as already said.
Is there another threaded hole underneath the tailstock that the key pin is meant to go in?
I'd have sort of expected the lock to be separate.

 

[ThornOfCamorr]

Yeah, I expected the lock to be separate as well. I expected a hole for a grub screw or a pin or something. Only thing I could find underneath the tailstock was a rather stiff spider

I think the hard use on the keyway is due to the broken/wrong lock key pressing against the edge of the keyway.