Re: [CAD_CAM_EDM_DRO] Building A Cheap DRO

Art Eckstein wrote:

> I "was" worried about the tension issue until I designed the housings that
> I used that include ball bearings. Not only will this allow greater
> tension, it lowers the friction required to turn the shaft.
>
> I thought about using the multi-turn idea but quickly discarded it for the
> very reasons you mentioned. The result was to build the system to maximize
> the amount of cable around the shaft (and keep a simple design) so the
> contact angle is 180 degrees. I am always trying to think of better ways
> and one that I recently thought of was to add a pressure roller (again with
> a ball bearing) similar to what is done on a tape recorder capstan. This
> should increase the pressure on the encoder axle without increasing the
> cable tension further. However, right now there are other projects on my
> plate and the darn thing works as is!

I would think the best way to do it would be to have the wire wrap one full turn
around the drum. This would make it possible to have a lot of tension
on the wire without putting a lot of side force on the encoder shaft.

Jon