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New Chuck - Drawtube Modification

jephw

Aluminum
Joined
Jul 23, 2020
Hi everyone.
I recently got a new Royal ID chuck for our lathe. The 3 jaw power chuck we have uses an adapter plate on the A2-8 spindle mount, while the new chuck won't need that adapter. This means that the draw tube for the 3 jaw power chuck is a little longer.
I measured and determined that if I shorten the drawtube approx 1.00" I will be able to use it for both chucks, as opposed to buying a different drawtube. I have 1"-1.25" thread engagement on both the chuck end and cylinder end.
So my question is, will I loose too much engagement if I shorten the tube? The drawtube thread is M100x2.
Any insight and advice is appreciated.
 

13engines

Hot Rolled
Joined
Jun 30, 2015
Location
Saint Paul
I would first talk with Royal about your machine. They will supply you with an adapter for free, and they won't take all day to do it too. I've gotten 2 adapters from them, and they were for 2nd hand chucks. Doesn't matter. I doubt your situation is unique. I bet they've seen everything.
 
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guythatbrews

Cast Iron
Joined
Dec 14, 2017
Location
MO, USA
The drawtube should be long enough to be impossible to come loose. If you cut off an inch it can screw into one end and out of the other. Not likely it will happen but never say never. I wouldn't cut it off.
 

DouglasJRizzo

Titanium
Joined
Jun 7, 2011
Location
Ramsey, NJ.
I would get another drawtube.
There is TREMENDOUS pressure on that when it clamps, and you really should have as much thread engaged as physically possible.
 
Last edited:

jephw

Aluminum
Joined
Jul 23, 2020
Thank you for the responses. I will contact Royal, and if they have nothing available I will get a new draw tube made.
Cheers!
 








 
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