Re: Caliper scales

I found the article- PROJECTS IN METAL, August 1993- Vol 6 No4. page
17-25

The title is 'DROS under $125 per axis' by Gene Martin.

My memory was not very good!

The pattern is actualy solid copper, with rectangular frames cut out.
The rectangles are 0.104 wide by 0.404 tall outside, and 0.096w by 0.396
high inside the frame- that is the frame width is 0.008". The pitch
between rectangles is 0.200

He made the part by coating the PC board with resist, then scribing the
frames through the resist. The board was then etched, making the frames.

The article describes a spring loaded scriber he put in the mill, with a
point havnig a .006 to .008 round tip. He shows a rather clever holder
with a spring behind the scriber.

The article also lists a Gcode routine that cuts a 28" long scale. He
also details a set of aluminum blocks miled out to mount the encoder
head.

I have a Mitutoyo DRO -the ~$700 one, that uses scales that are also PC
boards, but they are rectangles of copper on a clear field, not frames
like this article. So I re-state the suggestion I made eariler- if you
want to do this you better buy the calipers you plan to use first, and
take their scale apart and measure it, it may well be different.


ron