Steppers and the .INI file

[John Ross <johnr-at-i-link.net>]

  I've finally gotten my milldrill up and running with emc, but I have a few
problems.  First off I can't figure out how set the direction of movement
for an AXIS. The X and Z are backwards.  The X is ok if I set home on the
opposite side of the bed, but Z is a problem.  Instead of raising the cutter
above the work piece for rapids it's sinking it in.  Not a good thing.  I'm
assuming I can change the direction of movement some where in the .INI file.
All the reading I've done so far doesn't seem to make sense to me.  All the
AXIS settings seem to be explained in terms of servo motors and I don't
understand the correlation to steppers for these.  Second of all it looks
like the steps per inch are correct but I couldn't see how to set these up.
My last problem is the steppers are losing steps.  During a move the motors
sometimes stall out and chatter for a split sec then take off again.  It
doesn't seem to be a matter of the speed.  I can jog one axis at a time in
manual mode and it's real smooth.  It seems to be worse when I have more
than one axis moving at a time, but I've seen it chatter during a G0 on one
axis even with the speed set to 20% of max.  I'm using a Camtronics 5 Amp 3
axis board with Vexta 3v 4a 550oz motors.  The Board is set to put out 3a or
75% of max current.  I've removed the board and started searching it for bad
solder joints and solder bridges.  The signal lines to the board are in
shielded computer cable and grounded to the metal chassis.  I do have the
36v unregulated power supply in the same case.  Any help would be greatly
appreciated this is my first project with a CNC machine and I'm still
climbing up the learning curve.

Thanks

 John Ross