# Spindle Thread Adaptor



## Northerner (16 Jul 2013)

Hopefully someone can enlighten me..... probably a daft question, but here we go.

I have been gifted 2 chucks - a Poole Wood Supachuck and a Precision Combination Chuck by Craft Supplies Ltd. The threads on these are about 1 1/4" at least - I can't quite get the vernier jaws into them to make a proper measurement. I will work it out somehow though. The thread also looks huge. They are big heavy beasts, or at least they are to my novice eyes.

So - is it possible to get an adaptor to A) fit them onto a 3/4 x 16 tpi and also whatever diameter spindle thread is on the coronet major - it measures as .825" whatever that is in old money.

And B) is there a safety issue of using these heavy chucks on lathes such as the 2 I have acquired - i.e. an old Axminster belt driven jobby that I cant even see a model number on and the much sturdier Coronet Major which will be ready to be switched on in a day or two? The Axminster is a 1/2 hp and the cortonet is 1hp I believe.


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## chipmunk (17 Jul 2013)

Hi,
Well there shouldn't be any problem running either of these chucks on any of your lathes. They will be in-balance and so shouldn't give the bearings a hard time.

Your Coronet Major should have a 7/8" x 16 TPI thread which would be nearer to 0.875" than 0.825" but perhaps you measured the core diameter which will be about 1/16" smaller?

Getting a spindle thread adaptor for the Coronet may be tricky although you may be luckier with the 3/4" x 16 TPI which is a very much more common thread. 

You do need to measure the thread on the chucks though. If you measure the diameter of the hole in the back of the chuck in the threaded section first and then try to measure the crest-to-crest distance of the thread (perhaps over several threads to improve your accuracy) you should be able to approximate the main diameter of the thread by adding the crest-to-crest distance to the hole diameter. For example a 1" x 8TPI (threads per inch) thread will have a 7/8" diameter hole with 1/8" thread crest to crest distance.

You then need to look for or commission thread adaptors to fit. 

As an alternative you could always try selling your two chucks and buying two new (or 2nd hand) ones that fit your lathes? 

Hope this helps
Jon


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## joethedrummer (17 Jul 2013)

Hello,, try Peter Childs ,,they supplied an adaptor for a Sorby Patriot chuck to fit my Coronet Major which has a 7/8 x 16 spindle,, and very helpful they are,,just don"t go in the woodstore ,,it"s easy to spend a lot in there !!


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## Northerner (17 Jul 2013)

Thanks guys. Turns out the thread on the chicks is 33 x 3.5. 

Made some enquiries and its going to be more bother than its worth to try to find adaptors - for the cost of getting 2 made I might as well buy a new chuck with a spare insert from Peter Childs. Oh well, it was worth a try.


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## joethedrummer (18 Jul 2013)

Hi again,, are you sure Peter Childs don"t do something to suit,,they had excerts as well as inserts,,think I"d give them a ring,,


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## chipmunk (19 Jul 2013)

Take a look at the Charnwood website.

At least one of their chucks, the Viper 3 is M33 x 3.5 threaded and they sell inserts for £10 each to convert them to other threads. They have 3/4" x 16TPI insert but probably not a 7/8".

http://www.charnwood.net/shop/product/95mm-diameter-4-jaw-geared-scroll-chuck?cid=15

HTH
Jon


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## GoodGreeff (8 May 2014)

Hi Northerner,
I also have a Poolewood Supachuck that gives me limited use because one of the jaws is broken. I shall be grateful if you would please sell your chuck to me. Please phone me, 079 6372 2345. Francois Greeff, London.


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## nev (8 May 2014)

GoodGreeff":esvo2sdv said:


> Hi Northerner,
> I also have a Poolewood Supachuck that gives me limited use because one of the jaws is broken. I shall be grateful if you would please sell your chuck to me. Please phone me, 079 6372 2345. Francois Greeff, London.





Please note the date, Northerner has not visited the site for over a year, (So even if he still has the parts chances are he shall not respond. )

This info can be found on any post by clicking the 'profile' button... member17345.html


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