Re: MaxNC modifications

Andrew Werby wrote:

> [What is the advantage to using Aha software on the MaxNC, over using their
> supplied software?]

Stock setup way too wimpy and slow. While I'm sort of playing around
with my MAX,
I do use it in my business, and my dad uses it a lot (learning CNC in
his 70's!)
for some commercial work he does. We needed more performance. Tried the
step/direction
version with Cyberpak drivers and MAE motors and found we were losing
steps. Bought
the PacSci motors (from Bill Griffin, used, he has no more...), still
losing steps.
Bought Compumotor drivers (brand new, obs stock) from a motion control
outfit in
Florida (can dig up the name and URL), still losing steps.
Tried Ah-ha software both to try and cure lost steps, and for a better
interface, better
handling of radius comp, and the ability to search directories for files
and not have
to dump out of the program just to look up a filename. Still losing
steps btw, and have not
had time to dig deeper.

> [Were these easy to mount, or did you need to machine new mounting plates?

Plates use existing holes in MAXNC. Motor attaches to standoffs to
accommodate
helical couplers.

> [Where did these come from? Are they what Aha recommends?]

Ah-ha was the last item purchased, I'm sure they'd prefer we had bought
their whole
setup. Maybe we should have...

> motor mount plates with preloaded ball bearings to
> handle thrust loads,
> [Were these something you purchased or built from scratch? ]

Fabricated the plates and the shaft. Leadscrew attaches to the shaft
same as stock on the MAX.
Screw side has hex for wrench, other side has 5/16 nylock nut to adjust
play in bearings.

>
> BS&A ActiveCam nuts and 16 pitch screws,
> [Are these ball-screws, or is this an anti-backlash modification to
> standard screws?]

Acme screws, and an attempt to cure backlash. Mostly successful. Nut
screws into 1/4" AL
plate that in turn is screwed to saddle. These nuts are available in
V-thread, so you
could fit them to the stock screws EXCEPT that they mount outside the
saddle so screws
must be extended or you lose travel.

> [Do you think they would fit a stock zero-backlash nut?]

(referring to the Thomson econo ball screws) No, probably not. If one
wanted to play with
ball sizes, one could probably get down to little or no backlash. For
the size machine you
are thinking about, you will want the larger 5/8 screws that Dan
mentioned. The small screws
over long lengths can whip at higher rpm, and buckle under compression.
They would be fairly easy to adapt to the MAXNC and could be fitted to a
Sherline if one had
access to a full size mill for the modifications. Would be very tight
however. These little
ballscrews might also work well to CNC a smaller lathe. The sample I got
is useless for any
CNC testing as it's too short, but I'm going to purchase a longer screw
and two nuts to play
with.

Control systems? Heck, wish I knew. Still having minor lost step
problems. Wish I had a local
expert that could come over and tell me what I've done wrong...
For econo linear bearings in a router application, personally I think
I'd look around for some
surplus Thomson ball bushings and fully supported rails.