Re: [CAD_CAM_EDM_DRO] Doesnt ANYONE have this drawn up??? was: John's CNC plans???

Vince Negrete wrote:

>Jon, you've very much enlightened me on using the existing screw dimensions.
>Stupid me... I never thought of that! very cool!
>
>

All this stuff is hard to make. Some things, like the shape of the end
bracket, and
the J head on a Bridgeport, are free-form, hand-made surfaces ground into
mold patterns 50 years ago. I tried to measure many of these parts with
granite surface plates, angle plates, vernier height gauges, etc. and
still came
out way off, so holes had to be drilled out, shims inserted, all that messy
stuff. So, any way you can continue to use the parts that ALREADY fit
fine has got to be OK. I made my own yoke (the block in the center of the
saddle that holds the leadscrews) because I thought the Bridgport part was
flimsy. Well, it was a big mistake, and I had a HELL of a time aligning
things so the screws ran straight, etc. A number of ballscrew retrofits
make cylindrical adaptors that either fit the nut right inside where the
original bronze nuts went (that would require an undersized screw) or
the nut sits just outside the yoke on the end of the cylinder. I now
realize why they do that - to preserve the factory alignment of the screws
and nuts.

Just a rambling comment on some of the pitfalls I ran into when doing my
own retrofit.

Jon