Help please

[Meisear]

Hi,
I recently inherited this chuck from a good friend which as it turns out has the perfect fitting jaws for one of my projects. I was going to buy extra jaws for my nova chuck but it seems a shame that this one isn’t being used. It’s obviously quite old but works well and is in good condition.

Now the problem ! It doesn’t fit my lathe which has a shaft thread of 1inch 8TPI. I am hoping I could get an adapter but I don’t know nor can I find out the thread it has now. I can’t find any makers mark or information on it so I’m at a loss. My only other thought was perhaps I could get a 1” 8 tpi tap and after checking the size it seems to be about an inch so I wonder if anyone has done any thing similar? Any help or advice would be great and I hope this is the correct forum part to ask. Thanks

 

[DuncSuss]

A 1" x 8tpi tap that will thread steel is likely to be very expensive. (I have a tap to thread wood, but there's no way it would thread metal.)

I think your best bet would be to find a nearby metalworking company, or an old fashioned hardware store, and ask if they can help you (1) determine the thread specifications of the chuck, (2) figure out if the chuck has an insert to adapt the threads (such as the Nova chucks, for which you can get inserts to make the chuck fit lathe spindles with 1"x8, 1.25"x8, M33, and so on).

If the chuck doesn't have an insert that can be removed and replaced with a 1"x8tpi adapter, I'd ask if they could re-thread the chuck for you. It'd be a lot higher chance of running true if the threads were cut by a professional than by me.

 

[Meisear]

Good advice thanks. I had a thought that if I knew how old it was I’d then have some idea of the thread such as imperial or metric but then again I’m not sure if that right anyway.

 

[MikeC]

Beaufort inks have a range of lathe spindle thread adapters and Phil Dart there may be able to offer good advice
Mike

 

[howsitwork?]

to find the threa it has now take some blue tac and a strong piece of wood . Put the blue tac on the wood and after running a little fine oil into the thread apply it into the thread then withdraw with the blue tac ( hopefully ) still attached to the wood. You can now measure the thread using a thread gauge. Measure the diameter of the hole and that should give you a fair idea .

If the lathe is 1’ by 8tpi you can buy a ready made chuck back plate from RDG tools in 4 or 5’ diameter , it’s a common size . You then need to replace the one that’s on the chuck , assuming it’s removable ( most are )

If there’s enough metal ( ie it’s definitely smaller than 1’ ) you could have it bored out and re threaded if you know any friendly model engineering guys

 

[pittswood]

Hi Tim,

From the pics you have put up, that’s more likely to be a modified metal lathe chuck, maybe from a Swiss made or older German made lathe. Most wood turning chucks have the screw holding fixtures ruining centrally down the sliding jaws. Yours seem to be affixed around the chuck body, not the jaws.

As an old engineer, an adapter to fix within the chuck and be true to the chuck body threads, would cost, maybe more than the cost of a new modern chuck and set of jaws, which could be changed with others.

That’s just my thoughts.

Kelvin

 

[Meisear]

Thanks Kelvin and everyone else that’s all very interesting and all makes sense. I’m going to try the blue tack trick just out of interest anyway and take it from there. I don’t really need the chuck as I have 2 nova and a Rutlands small one, but I have it and it bugs me that I couldn’t find any way of getting to use it. It came with several sets of jaws so it could be useful but it’s not a game changer.

Must say I’m impressed by everyone’s efforts to help and hope to be able to help someone in the future