Thread: Anyone have any thoughts on the OBM grinder?

Originally Posted by jfk742

How’s the balance? That’s pretty cool, if I was better at cad I would definitely look into a 3D printer.

If you have a shop vac that will allow you to pipe into the exhaust side that could work. Built in filter, positive air pressure, or just use it passively for its filter with your motors fan pulling air.

Are you going to shroud the fan to keep any debris from sneaking in the gap?

The balance is good! When I designed the center part, I added a little mass around the keyway cutout to make sure things were as even as possible, and that seems to have pretty much done the trick. It’s probably helped by the drive wheel having significantly more mass on the other end of the arbor.

I’ve got a small shopvac, but space doesn’t really permit me to use it here.

My plan is to rivet together some sheet metal with a gasket between the rivets to make a shroud that has enough stickout to put some sort of filter over the end. Maybe an automotive filter. I’ll definitely be making certain there are no ways for dust to get in at any point on the motor or the electronics.

I figure running the exhaust over the electronics should let me keep dust out of them. The fan seems to be generating actively good flow.

Okay, this is hilarious.

File under “Off the shelf solution”:



It’s just the filter for a shopvac. It perfectly fits with a snug, air-tight seal, right onto the motor housing. There’s plenty of room around the fan blade.

I’m still probably going to need to make a short shroud for aerodynamic reasons with the fan — the end of the motor it’s blowing into is large open, but has enough flat spaces that there’s a lot of turbulence in the airflow and it doesn’t really push all the way through the motor that well unless the fan is inside of some kind of tube.

That's awesome!