I built the Burly, tore it down and upgraded to Primo. I built the MP3DP, and it serves me well. I should probably build a Lowrider to cut the top out of this, but I think this is just going to be my beta table. Plus I already have the conduit from the Burly.
They seem to move fine. I was just going by the docs and Old Guy Coding’s belt threading video. As far as I know, that’s how they are supposed to be mounted. I was a little confused too before I started the build while watching the video because I noticed the belts had to twist 90° to feed through the center idlers. I haven’t hooked up the electronics to it yet so I guess I’ll find out then, but there doesn’t seem to be any more resistance as it approaches the limit switches.
I assumed this was an intentional design decision by @vicious1 to minimized the vertical dimension of the ZenXY mechanism.
Looking at the above picture, the whole mechanism tucks up inside the table apron, but if the steppers were rotated 90* to remove the belt twist the steppers would probably be visible below the apron.
Pulled my CNC shield from the Primo to test with another Uno I have laying around. Running GRBL and sending with UGS. Made a pattern with Sandify and ran it. Moves correctly. Gotta get the limit switches wired. Work area ends up being X=290 Y=800
Are there any SDcard/LCDs that work with GRBL if I want to cheap out? Or should I just spend the $10 extra bucks and get a RAMPS seeing as though I also have a spare Mega2560?
Hmmm. Maybe make it a feature? Make an insert out of a different wood to cover it? Maybe fill it with resin? Maybe just fill it and paint the whole table?
OK, got the bottom panel mounted and put some test soda down. Realized that I cut the opening smaller then I wanted so now I either have to shorten the Y tubes for the end-stops to operate, or finish cutting the top hole bigger. I put the routing fence on the cut line instead of the fence line. Good thing is if I re-cut the top, I won’t have that little filled tail any more. Maybe it’s a sign?
The ball isn’t regulation. I don’t even know where it came from, maybe an old mouse? It just happened to be in my random screw bin.
Man the movements on this thing is LOUD. I’m using DRV8825s at about 3500mm/min but there is a lot of rattle from non-seated bearings. Is there any adjustment for the center bearings seating? I did remember reading something @jeffeb3 did with wrapping the tubes with heat shrink. Any other ideas?
Edit: Found the thread I read about the heat-shrink. Also turned down the feed to 2000mm/min and that made a huge difference.
Just got back from Depot Del Casa. Bought a few metal balls from 3/8" up to 5/8". I measured the one I had and it is 19mm~3/4". I figured I could try out different ones and maybe get some tighter patterns. At less then a dollar to somewhere around a buck and a half, I said hell with it. 1/4" seemed too small though so I passed on that.
I was just going by the 
