Re: [CAD_CAM_EDM_DRO] Why not use threaded rod leadscrews?

Paul wrote:

>Stainless threaded rod is cheaply available in 1m (39in) lengths.
>I know the V thread profile is not square, not ideal for loads, not
>ideal friction wise, greater wear/backlash problems, not so
>linear.......blah, blah
>
>BUT I can save a *huge* amount of money on a 1mx1m wood router (3ft
>6in x 3ft 6in). I've been quoted over £100 ($180) for a new 1 meter
>leadscrew which I think is OTT.
>
>

Yikes! A wood router needs to move fast. Most threaded rod is pretty fine
thread, meaning it will have to spin very fast. You don't mention diameter
anywhere here, but thin, long rods spinning at high speeds are dynamically
unstable. (Technically, the first critical speed is low.) For a 1 M long
shaft spinning at several thousand RPM, you might need a diameter of
50 mm or more to avoid turning it into a pretzel.

>Also is there a cost-effective source for rack and pinions? All the
>large 8ftx4ft pro routers use rack and pinions.
>
>

Yes, and now you know why they do so!

Jon