Paul wrote:

Very elegant solution to motor mount brackets

Frank.

That is the trouble with those NC mills. They

are expensive and

they MUST be paid for.

Paul Lamar

Mark Wrathall wrote:
Paul, I am suprised you never added CNC to that Bridgeport of yours. There
is an outstanding Linux machine control program (EMC Linuxcnc.org) which
runs standard G-code and controls either a stepper driver through the
parallel port or servos though the servo-to-go card. I bought an excellent
light duty stepper controller from a guy in Germany to learn this stuff
(NC-Step.de) , but with your electronics experience, I'm sure you could
easily cook up your own, or replace the power amp stages with something
powerful enough to drive big steppers on the bridgeport.

I am still on this CNC learning curve, but if you want any pointers to

info

or sources I have been trolling the internet quite intensively on this.

Mark

I don't have a Bridgeport. I wish I did. My hangar neighbor has one
however. I have a cheap Chinese mill. I don't really want to go into
business. I could, I guess, finance a NC mill and start making parts.
It is the rest of the business I don't like :-)

I have been following those developments sort of. What worries me
is the lead screws among other things in the Chinese mills would probably
have to be changed as they are not up to real mill standards.
Paul

You have to be careful with these types of retrofit kits because even on a brand
new mill they do not supply much accuracy or repeatability. The only decent method
of accuracy for these machines is the glass slide, which = big bucks. Why do you
think that a retrofit Digital Read Out (DRO) of decent accuracy costs about $1.5K
without installation costs/time.

See -
http://www.mscdirect.com/PDF.process?pdf=1835

I am not saying that the lower cost units are crap but that they produce a wider
tolerance envelope which may be acceptable for an application. But when I went
looking for a mill I did quite a bit of research and a lot of hunting to come up
with my current unit which can produce work that usually far exceeds my
requirements. (WtF, i'm an engineer and keep looking for perfection!)

But with the good, comes the bad. One Z-axis board - POOF.  X-axis slop is
increasing and must be addressed. Spindle runout is starting to annoy me and will
require a rebuild / rebearing in the future. But even with all this crap I can
keep true position within .0005" over the range of the over travel limits (smaller
working area than manual version though.... ). Yup, I know that over the y travel
that it climbs .0015" due to it made a shitload of waveguides and wore the knee
quite a bit.

Answer: Don't skimp on $$$ if you want close tolerances that your life may depend
upon at altitude.

Blake

 
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