[How do I?] Spindle Blank And Spindle Registers

[mattthemuppet2]

Hi all,

in the process of (slowly) making a backplate for a 4 jaw chuck. I want to make a spindle blank or copy of the spindle nose to check for fit in the backplate so that I don't have to take the chuck off. It's for an Atlas 618, so 1x10tpi. Is it okay to use a relief groove between the spindle register that locates the chuck on center line and the threads? The spindle nose has the thread going straight into the register, which then leads to the 2nd register that the backplate butts up against.

In other words, the spindle is threads>register>perpendicular register.

Is it ok to make my copy/ blank as threads>groove>register>perpendicular register?

I'm worried about being able to open the halfnuts and back out the tool at the exact same point, so a relief groove would allow a rotation or two before I stop the spindle or back the tool out.

2nd Q - when do you cut the ID register on the back plate? Before cutting the threads or after? Does it matter?

thanks!
matt

 

[JimDawson]

I don't think that a relief groove would hurt anything. I don't think it matters at what point you do the register as long as you do all of the machining in one setup. The only thing that comes to mind is that cutting through the threaded part would give you an interrupted cut until you got to the thread root.

 

[mattthemuppet2]

thanks Jim, I appreciate that. I'll have to do some measurements on the spindle (well, obviously ) but I would expect the register to be a slightly larger diameter than the major diameter of the threads, so cutting the register first might simply be easier. No need to cut threads on more steel than necessary!