Spiral Twist on a mill

[enginemaker1]

Has anyone done this.

I want to make a spiral twist shaft with a pitch of 1 per 6 inches. I was thinking of mounting a quick change gear box on my Bridgeport driven by my lead screw with a small chuck. I would also mount a tail stock to hold the other end of the shaft. By using the gear box I could change the pitch. So if I turn the lead screw I would create a spiral twist. My Hendey lathe only has a 1-1/2 to 80 pitch selection.

Has anyone done something like this?

Tom

 

[vlmarshall]

There's a recurring job I do at work that is a 1-in-21" twist, three grooves inside a graphite bearing... I cut 'em on a Bridgeport with a geared dividing head, and an angle head on the mill.


I wonder if it's possible to set one of those micro lathes on the table, and gear it to the left side of the X screw...

 

[bearcar1]

As cheeseball as this may sound, Sear's catalog stores used to sell a woodworking device that had the operator mount a router to and by the turn of a handle it would cut a spiral groove to crate decorative legs and columns for furniture etc. Perhaps you could investigate one of those devices and get some ideas of the mechanism involved or perhaps even adapt the device somehow. Yeah, yeah, I know, go back to my corner and stay there. :big:

BC1
Jim