Re: [CAD_CAM_EDM_DRO] all-thread lead screw( was Re: Linear rail & ballscrew size suggestions

dave_ace_me wrote:

>
> Doug had been the one on here that supported the 6 times longer nut
> over an all-thread leadscrew.

You bet. To be specific, I am using a 1" dia acme leadscrew, and
a 6" long UHMW nutblock (that gives you the 6 times). However, even
three times is pretty much sufficient (a 1" dia acme coupling nut is
3" long).

> What I did was to take a 6 inch piece of Delrin/Nylon and tap it with
> a 1/2-13 thread. I turned the OD to 3/4 for most of the body with a
> 1.25 shoulder. I pressed this into a pillow block bearing.....
>
> As I had mentioned before, design for the largest parts you may ever
> use, I left room for a 1 inch leadscrew and anti-backlash nuts, just
> for that day off in the future.

For your interest, the 1" dia (leadscrew) acme nut is:
- 1.625" across the flats
- 1.875" diagonal across the hex
and
- the OD can be turned down to 1.500" dia for a press fit
(or fine threading) into Delrin as you describe above.

Keep in mind although there will be no backlash (axial play) to speak
of with the long acme nut, there will be radial slop, so you can't depend
on the leadscrew for transverse rigidity (it needs to be combined
with some sort of linear rail to provide that stability).

Doug Fortune
http://www.cncKITS.com NEW -> 1KW power supply kits


























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