Kurt Drawbar Assistance

[cantabrigian]

I'm making a new drawbar for one of my machines and can't decide how much thread engagement to use. It is a 40taper machine without pullstud... the Kurt power drawbar just engages the collet chuck. The original drawbar is thoroughly mangled and I have a feeling it wasn't long enough out of the box (I'm not the original owner of this machine). Any advice as to how much thread to engage on a 40taper chuck?

thanks!

 

[astjp2]

I set them up by feel, your collet chuck needs to be engaged with the 2 lugs before the threads start, most of mine have 5 ish thread before it pulls tight. we have a general supplier of drawbars and I wind up trimming them in the lathe for proper fit. If its not engaged in the lugs first, it can damage the lugs or tool holder. Tim