Z axis error woes

[HankMcSpank]

Hank

This is definitely a problem with the rails not being at parallel heights? Now i would check that the supports are equal, bearing cases are equal etc.

....but wouldn't leveling the bed at least workaround that?

Z Axis update: It's just too 'parky' in my workshop at the moment (no heating it must be nigh on -5c in there) 'm keen to sort this out but not *that* keen!

I'm beginning to think this is a combination of factors....

1. p1ss poor leadscrew.

2. poor stepper resolution combined with steps going awol (my Allegro A3977 IC based steppers no longer work at anything less than full stepping(1)....that's resolution of 0.0075mm per ste, which sounds fine it doesn't take many steps going missing to cause chaos when your target depth is just -0.12mm! I use an easy cnc 3 axis board.....on the face of it, it's nice, but I;ve had no end of problems with the IC holders (poor connections with the IC). I have a spare tb6560 3 axis board - made by someone that's partial to boiled rice - laying around that I can press into play over the coming days (while trying to source some more A3977 ICs for my easy cnc board!)...at least then I can go with 1/8 stepping.

3, too high expectations for an entry level machine....I was taken in by the promotional youtube video..... http://www.youtube.com/watch?v=TYAfNTvgTak (note - thru hole, therefore wider tracks, therefore you can go deeper with the v cutter ....SMD is hust too challenging for this simple CNC machine offering)

gameplan....

1. don't venture into the workshop until my tea can stay drinkably hot for more than 30 seconds.

2, Press my spare tb6560 stepper board into play & go with 1/8th stepping

3, Start saving for a proper machine and leave this one to those who make parts out of balsa.!