I can't help but think this might make a good mill/printer combo. If you attach a print head to it you have no need for bed leveling, and 3 leadscrews would provide more accuracy than most of the printers around.. And then you could swap out for a spindle and cut aluminum when the need arises

 

Hey OB owners
What is the max rapid and cutting speed you've been able to get in aluminum?
Anyone experiment or use flood/mist coolant? Where did you get some bellows to protect the C beam?
Still super tempted to get one of these, once I figure out a good spindle. A 600w, low RPM air cooled spindle would be perfect for this thing.

 

Here it is, mirror it for the other side

 

I've just completed my build of the MiniMill, and I'm digging into the software. I'm using the Gradus M1 Pro controller with Bigfoot BSD109A drivers and 269oz in. Nema 23s. I'm running everything at 36V. The Gradus has Grbl 0.9.

The Bigfoots are currently set for 1/32 microstepping (no jumpers), and from what I've been reading, I probably don't want that. I do intend to eventually cut 1/8" 6061-T651 plate with this. So should I dial back my microstepping?

Also, I've been watching the C-Beam video for configuration of Grbl-panel and noticed that there is not a folder similar to the "CBeam Machine Control Software" folder posted for the MiniMill. How much trouble will I get myself into if I use the info there?

Great kit by the way - Thanks!
Scotty

 

Yes - Thanks Mark!

 

So I see you've got ~200steps/mm. That means you are using 1/8 microstepping, correct?

 

I am attaching below my grbl "defaults.h" entry (for grbl 1.1f) for my new MiniMill. It's based partly on the grbl settings Mark posted in the Build tab, and partly on the OXCNC entry in defaults.h. You can copy and paste it into your defaults.h and then define DEFAULTS_MINIMILL in your configuration.h . Thanks for the settings Mark!

 

My MiniMill Y-actuator has a bit of side-to-side play of the lead screw in the bearing at the jog-knob end. It sometimes "clicks" during operation. (There is NO fore-aft play.)

Is this normal, does it matter, or can it be adjusted out somehow?

 

I just finished my mechanical build and I have the same issue on the same axis. I think maybe the threaded rod is slight smaller then the ID of the bearing.

 

I just finished building my OB MiniMill as well. I just ordered a Gradius M1 Pro with the Bigfoot drivers but for the time being, I have an SBase v1.3 lying around to at least test/calibrate. Doing basic calibration and try to do a circle it actually looks crooked. I reassembled my X (at least from what it looks a problem with the X axis) but still getting the same shape circle. Any pointers on where to look for next?

thanks!

 

thanks Peter. I think I solved it but not 100%. I can wiggle the connection between x and y just a tad bit, tightened that and it looks like it worked (at least more circle-ly than the other 2 ☺️)

Probably need to start building my enclosure and permanently screw this on a platform.

 

I just screwed it temporarily on a piece of plywood. As far as I know, it's not shifting. Might need to double check the wheels on both x and y. My question about the wheels, right now, I think I maxed out my eccentric nuts (no more space to tighten them up). My wheels are not moving when I try to roll them manually with my fingers but the carriage is moving when using the knobs. When I'm building the carriages, I know I can slide them just fine prior to installing the motors

 

I really like the vise and want to make one. However, i don’t have a source for reasonably priced aluminum bar stock. Can anyone here suggest some sellers or strategies for locating sources?

 

Thanks, Rick. I’ll check it out.

 

I completed my MiniMill build this past weekend (see My MiniMill is just the start). Something I noticed while building it was when installing the end plates on my X and Y axis rails, I had to push the lead screw down about 1 mm on each end for the bearings to slide into the holes of the end brackets. I followed the build video to the tee, so I'm concerned about this. The problem with the lead screws manifested itself when operating my mill for the first time. The motors seemed to slip and there was a lot of friction type noise coming from the lead screw and lead screw nut when approaching the maximum end of travel. I did not need to tighten down on the anti-backlash set screw any at all during the build and tightened down on the end plate screws after getting the bearings in place. I have to keep my lead screws well lubricated to prevent the motor slipping and noise. It appears an extra 1 mm shim (in addition to the 3 mm shims) between the bottom of the gantry plate and lead screw nut would solve the problem. I will let you know if works.

Thanks,
Michael

 

Hello.

Could someone help me. I'm building MiniMill. How tight wheels should slide over the C Beam profile? Plate should slide easily over the profile, or it must require force to move by hand?

 

Rick, this makes me curious about the "clicking" I get near the end of my travel on X and Y. The video does show putting a shim between the wheel and the spacer. Now I wonder if this is why I get the clicking. What is the correct way - with or without the shims?