Changing the threaded connection on a chuck

[Mike313]

Hi All,
I'm thinking that, at some stage in the future, I may want to invest in a better lathe. My current lathe is a 3/4" x 16TPI and the lathes I have been looking at are M33 x 3.5. I have an Axminster SK-114 Precision chuck (older model with the black back plate) threaded accordingly. On inspection, the back plate is attached by 3 'star' screws. I haven't ventured to remove this plate as I don't know what's behind it or what damage I might do, hence my question to those with more knowledge - can the back plate of this chuck be removed and replaced with a back plate threaded M33 x 3.5? If so, is it something a mere mortal can do? Or should I be looking at buying a new chuck? I should add that I don't want to use one of those adaptors you can get as they seem to push the chuck out from the spindle which seems to me to be best avoided. Advice much appreciated.

[The Bowler Hatted Turner]

Mike I have never used that particular chuck but most chucks allow you to change the backplate. However, the safest and best thing to do would be to contact the technical department at Axminster Power Tools and ask them directly. They are very helpful and knowledgeable.

[Mike313]

Thanks BHT, I intend to contact them Monday but just thought I'd ask on here in case anyone had actually done it. The chuck seems to be well regarded so, when the time comes to splash out on a new lathe, it would be a boon if I could (cheaply) modify it rather than have to sell it and buy a new one. Thanks for the reply

[Redtails4]

Hi
On your old axminsters chuck you have a plate with three screw with a star shape in the heads ? These screws are torx screws and are usually no say from no six through to the
High forties the torx screw is a strange screw to use on the back of a chuck also the odd
Number ,i would have thought caphead Allen screws would have been a better choice.
Now to that plate, this can be fastened lying on the surface with a couple of dowels to form
A register .or the back of the chuck has female register so when the back plate is removed and put back the whole chuck runs true this what would happen in both cases.
You should be able to tell how the back plate is fastened with a little look-see
Myself i would go for the second option .
That is how metal lathe Chuck's are constructed. And with there early Chuck's axminsters followed that pattern. if you want to take it to pieces get a small centre punch and Mark both the body and the back plate side by side before you dismantle.
Good luck

[Redtails4]

Hi
Sorry i should have mentioned one thing ,it's not by any chance a axminsters precision chuck?
Because i think you can still get the back plates from axminsters?
Are there a series of holes radially on the back plate used for indexing?

[Mike313]

Hi Red,
Yes it is a 'Super Precision Chuck'.
I'll try attaching a photo,
Mike.

[Mike313]

It's actually in better condition than it looks in the photo. I haven't cleaned it up - what might look like rust is in fact wood dust

[John Plater]

All hearsay as I have no direct experience. Many have said that the older Axminster chucks are better than the modern ones and worth keeping all the time they work nicely.
ATB John

[Derwent Woodturning club]

Mike, I've had a look at Axminster's website and as far as I can check, the SK114 is manufactured with the thread as part of the body. The Torx screws just hold the backing plate in place, not an actual thread backplate, as was done with their earlier chucks. What adds to the confusion is that they use the term 'Super precision' in the title of their older chucks, where you can still get some backplates, but your SK114 is termed an Evolution chuck but they still put 'super precision' on the plate at the back of the chuck.

A lot of people have considered this a backward step as you can't change the back part of the chuck when you need a different thread but Axminster consider this 'one piece' construction ensures a more accurate chuck.

Unfortunately none of this helps you achieve your main objective, and I agree with you that thread adapters introduce problems, namely run out accuracy and they take up a lot of bed length. I also think they put extra stress on the headstock bearings.

I would concur with John (BHT) and give Axminster a call as they must know exactly what options you've got.

[APH]

Calling Axminster is the only way to go with this. They've never listed the SK114 backplates as separate items, so it won't be a DIY job.

It's possible that someone with access to a full metal working workshop might be able to recut the thread for you, there looks to be enough metal there. Not a trivial job I would have thought though.

If Axi can't help, sell it off via eBay and buy a new one. A chuck of that quality should hold it's value pretty well.

[Mike313]

Thanks, everyone, for the replies. Certainly, as has been said, from the 'outside' the chuck looks like the thread is a part of the back plate. I've already sent an e-mail to the service people at Axminster. And I hope to be in touch on Monday. I'm post again when I hear from them as I'm sure others would like to know if it's possible . . .

[Redtails4]

Hi
That photograph is of a brand  new sk114 chuck.
They did a chuck which is much sought after today ,which is the one i had in mind .
Your sk114 is a direct threaded chuck and cannot be altered without running the risk of having the chuck run out badly or at worst ruining a good chuck sorry mate.
You could ask axminsters for there advice.

[Mike313]

Update.
I sent in an e-mail enquiry to Axminster about this over the weekend and received a very prompt reply this morning. The reply states "Thank you for your enquiry. Due to the threaded part of the chuck being the main body of the chuck it is not possible to replace the thread. All I could suggest is that you sell the current chuck or if you are selling the lathe that it fits perhaps include this as a package as a new chuck would be needed to fit a different thread." So it looks like I will have to sell the chuck and then buy a new one.
I'm going to post a separate question for advice about chucks and jaws.
Thanks all for the replies