I’m taking on a new project and I’m looking for some input. I've currently got a little 2 wheel 6” bench grinder and of course I want something bigger and more powerful. It’s got a tiny motor and I feel like I’m routinely changing wheels for different grinding applications. I’d also like to have a buffer, disc sander and belt grinder at my disposal. I don’t have room or $$$ for all those independent machines so I’d like to build some sort of mulit-purpose machine.
I scored a great condition baldor 3hp compressor motor for 50$ to power it. I’m going to either use a VFD or a pulley and v-belt system to control/adjust speeds for given applications.
Design wise, I plan to mount the motor near the floor, run a belt up to power a shaft that has opposing ER40 collet chucks on either end. I can then make various arbors and attachments to plug into the collet chucks to spin grinding wheels, buffing wheels, disc sander etc… I’ll have a way to easily mount guards and adjustable tables as well.
My biggest questions are:
What is the difference between a typical grinder/buffer motor and the compressor motor I have? If its just the enclosure its not a big deal because it won’t be exposed to grinding dust or anything like that the way I’m envisioning it. I've heard they have more torque? Can’t imagine why that would be a problem…. can’t find any definitive answers to this online.
Will the ER40 chucks be relatively safe spinning at high speeds while i apply normal grinding/buffing pressures on 10” wheels? I’m planning on ⅞” or 1” arbors and mounting the shaft bearings as close to the chuck as possible for support. I’m assuming it’ll be fine since they are designed to experience (presumably) much greater forces when spinning end mills through materials.