Combine a 2x72 belt grinder & 9" disc ??

[rabler]

Im kind of new to all this. I think my confusion comes from seeing my bench grinder with 110V and variable speed.

I'm no expert. My understanding is VFDs, changing the frequency of the AC sine wave, is the modern approach for larger motors. Older technology, and small motors are often DC motors that are controlled by voltage. Stepper and servo motors are another option, more expensive, that require sophisticated controllers.

 

[xr650rRider]

I built a 2"x72" belt grinder using Brian House's plans and even bought the pre-cut metal back before prices went nuts. I used a 2HP 3 phase with a cheap Amazon $89 VFD and it is a metal eating machine. The pre-cut pieces made it a very easy to build project. I also have a 12" disc grinder that I bought from Harbor Freight for maybe $120 and it works well. I'd rather have them separate machines but then I already own both. The disc grinder is the go to for doing stuff like shaping recoil pads for guns. If you use the 2" for knives shaping/sharpening or where you need to change belts quickly, I don't think a disc would be practical. I added a buffing attachment to the 2" grinder with dual buffing wheels but it's driven by the belt and if your not careful, you can cause the belt to jump off the drive and is a pain in the arse. It really needs a different drive belt but I haven't found one yet.