Re: [CAD_CAM_EDM_DRO] Bridgeport Series 1 conversion and other st uff

eGroupsCDH wrote:

> Hi Jon,
>
> To measure backlash on the machines that don't have power I was going to try
> to uncover the stepper motor shafts and either mark them or attach a clamp
> to them such that I could rotate the shaft one way, back to start and then
> the other way and back to start using a dial indicator to see the difference
> in readings on returning to the start position from different directions.
> If the table moved when I pulled on it I'd be surprised. How much backlash
> would be expected in a good ball screw/nut? How much should be considered
> "no-go"?

Well, good is zero backlash. .001" backlash would not be too bad, as the oldest
machines only have .001" resolution, anyway. The later models have .0005"
resolution. The ballnuts can be refurbed with oversize balls to take up the backlash
(or possibly just the correct size, as the balls wear down in size first).

If you find a lot of backlash in the niddle, but less backlash at the ends of travel,
that indicates a worn ballscrew, which is a big problem to fix.

> I have BobCAD V17 and the documentation is terrible (also the "movies" don't
> work for me). It took me hours and hours to figure out that the dashed
> lines shown in the pocketing example actually meant something to BobCAD! I
> also have trouble getting the correct contour identified (especially with
> lots of lines in the area) and it wasn't until I called tech support that
> they told me that right-click could be used to end a contour. They now have
> "training materials" available for $195 that includes an extra license
> "seat". That's a steep price to pay for documentation you should have
> gotten in the first place and I can't use the extra license because I'm a
> one man operation. They said that if I ordered the manuals to check them
> out I couldn't return them and they couldn't lower the price by removing the
> extra license .....

Yup, sounds similar to the Bobcad 16.1 mess!

Jon