New Chuck - Drawtube Modification

[jephw]

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]

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.

 

[guythatbrews]

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]

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.

 

[jephw]

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