Intro & Retrofit Questions

Hello List:

I've been looking, off and on, for a list
such as this for several years. I finally
stumbled onto it a couple of weeks ago,
subscribed and have been looking over some
of the archives. Such a list seems a
natural, a topic of interest to many and in
combining machining, electronics and
computers it is complex enough that
collaboration is very advantageous. Good
to be online.

I have a home shop with 14x36 Goodway
lathe, SuperMax knee milling machine, TIG
welder, Oxy-acetylene, bandsaw, horiz.
bandsaw and related tooling. I've had most
of this for about 15 years, used for this
and that including recumbent bicycle frame
building. I have a 450MHz Pentium III
system running NT for designing and general
use. I've been involved with computers for
some 25 years starting with a Z80 system
running CP/M. I'm now a computer user
rather than getting into the internals much.

I've wanted to retrofit the mill to CNC for
at least 10 years and I'm now ready to
spend the $ for this. I think access to
this list will make this project much
easier.

So, after reviewing the archives and
thinking about this conversion I have a few
questions I hope you can answer. I'll
put this into several e-mails as they cover
different elements of this conversion. But
let me give an overview here first.

The milling machine is a SuperMax from
Yeong Chin in Taiwan. It is dated 1980 and
I obtained it in 1985. Since then it
hasn't been used heavily and I believe is
in reasonable shape. It is a Bridgeport
copy, or close to it. I'm planning to
install steppers of about 550 oz-in using a
2:1 reduction through timing belts for X
and Y. Z axis on the quill with a ball
screw but haven't worked out any details.
Half stepping (400 step/rev ?) would then
give (800 step/rev at .2 lead) .00025" per
step. Should give reasonably smooth curves?

I want to covert to ball screws. I suspect
the SuperMax isn't a close enough copy to
use a Bridgeport retrofit package. So this
will take some doing.

I want to avoid proprietary systems so I
plan to connect the steppers through a
drive to a PC printer port. This should be
generic and allow use of several software
CAM packages.

For the CAM software I hope to get linux
and EMC running. This sounds like the most
cost effective solution if ones time isn't
included. If not I'll go to a similar
package under DOS.

This would get me from G-Code to parts. I
haven't thought much about the G-Code
generating software. At work I have access
to several packages which will generate G-
Code but I haven't done much with them. I
know MasterCAM is available as is Pro-E and
I-Deas but I don't think anyone has worked
with the tool path generation modules of
the last two.

I would be ecstatic even if I had to hand
code the G-Code. It would beat the heck
out of turning the handle on a rotary
table, and making the second part would be
even easier. :-)

I'd appreciate any comments on this you may
have. I'll send questions on the individual
problems. TIA.

Hugh Currin
Klamath Falls, OR