Using SK114 chuck in reverse

I am new to woodturning, recently having bought and reconditioned a Union Graduate lathe. I purchased an Axminster SK114 Evolution Chuck which has left and right handed threads for use either side of the headstock. I have a Newton Tesla variable frequency drive fitted which allows the lathe to be driven in forward and reverse.
Is anyone able to advise how I can safely use the SK114 in reverse (for sanding etc.) without the risk of it unthreading?

You need the locking sk114 with the Allan screws

Thank you for the reply. There does not appear to be a variant of the SK114 chuck on the Axminster website which has Allen screws for securing to the spindle. Having checked, some other manufacturers do incorporate an Allen screw for this purpose on their lathe chucks.

That’s funny just received mine I think you should phone Axminster tomorrow and I am sure the will sort you out with one

Interesting, I hadn’t looked at the M33 thread variant; which has reverse locking. Mine is 1.5 inch 6tpi thread and reverse locking feature does not seem to be available. I will give them a call to find out why, thanks for pointing that out.

The M33 Threaded version is the only one with this version of locking.

The others use a different method, open up the jaws and look inside at the back there are two threaded holes with possibly a grub screw fitted.

Remove the grub screws and make sure the chuck is tightened tight against the collar then using a twist drill through the grub screw holes, drill a dimple in the spindle collar, this only needs to be a couple of mm deep.

Now refit the grub screws and these will act as the reverse lock.

Many thanks for the suggestion of how to resolve this problem. I have just had a look and can’t locate the threaded holes or grub screws. I have attached photographs from different angles of my chuck. Any suggestions as to where they may be?

Nigel it appears that I infact have the locking version although when I purchased mine it was not an option it was standard.

Thanks Richard, I will follow it up with Axminster to see what they suggest.

All the chucks I’ve ever seen with reverse locking screws have had a collar on the back. I’ve never seen this collar on any SK114 until I specifically looked on the Axminster website for one and found this picture - an SK114 with a collar and locking screws!