Re: [CAD_CAM_EDM_DRO] Re: Make your own linear scales

ballendo wrote:

> Jon,
>
> What is your "gut" feeling about a homeshop guy or gal creating glass
> scales like this? Could we do the etching necessary?
>
> What other options do we have for creating our own linear scales?
> (Besides cable/encoder)

The etching of glass scales is pretty easy. The TOUGH part is getting
the metal depositied on the glass. This is generally by vacuum deposition,
which would take a LOT of exotic metalworking to build a vacuum
deposition chamber! It might be possible to use those first-surface
mirrors out of laser printers and supermarket scanners for the blanks
for the scales, but you'd be limited to the longest ones you could find.

>
> I've always thought the "spherosyn" could be "home-shop-able"
> (precision ball bearings in a tube, read capacitively sin/cos)
>
> Also have thought about the old "wire" tape recorders...
> What about recording a sine wave (signal generator created), and
> reading it with a std. recorder head. Then looking for a way to have
> TRUE metal tape. Iron oxide?

Most of these schemes require interpolation, which makes it a lot
more complicated. Why not just get good ballscrews and cheap shaft
encoders?

The magnetic track scheme would need meagnetoresistive heads, which
you might be able to pull out of a disk drive. But, you'd need to build a
VERY exotic machine to accurately record the pulses on the wire/tape.

Jon