Re: Spindle motor drive belts MAXNC 10 UPDATE

Hans,

First mod I made to my MAX was to toss the spindle motor into the spare
parts bin. I fitted a Sherline DC motor and control. It's a tight fit
betwen the Z stepper motor and the spindle.
Here's a link to a pic of mine

http://www.prototype-design.com/images/Shermax1.jpg

You can see here the adapter I made to use a Sherline spindle as well.
If you (or anyone else) is interested in this adapter, I can post the 3D
wireframe in DXF format.
You can see that I'm only using one bolt on the end plate on each stand
off, and have no problems with vibration or flex. I think part of your
problem is the standoff isn't seating well against the sheetmetal case.
MAXNC is getting better at spin control. I seriously doubt that flex was
engineered! The whole thing is cost driven more than anything, and it's
a decent bargin alright, but some mods will go a long way towards making
it more useful.

BTW, you can see in place of the stock motors, I've made thrust plates.
There is a custom stub shaft passing through dual ball bearings.
With a nylock nut for adjustment, I can dial out backlash and relieve
the motor of thrust loads. Note, this does nothing for backlash at the
leadscrew nut... The Sherline spindle adapter has a constant force
spring inside that is attached to the thrust plate. I forget, but think
it's rated for 7 lbs, and it releives the Z motor of some of it's load.
Can also post a DXF file of the thrust plates and the stub shaft.

As for your setup, I would suspect that either the V groove angle is not
right on one or both pulleys, or possibly one of the pulleys V-grooves
isn't concentric to the bore. Does the belt vibrate or flutter a lot?

Jon