Hexmonkey,
My correction sorry I was off by 25 rpm's at that motor's speed.
That motor looks to be a through-bolt style motor so one option would be to use long bolts to go through the holes that are in the face plates and bolt to a piece of wood or whatever. The one thing I would I would caution is that those holes are generally small and fit like an #8-32 so I would still put a board underneath for support and not just rely on the bolts to support the weight of the motor.
I would bet that is 10-24 threaded rods just on the ends vs 8-32.
With 90 degree 14 gauge or thicker plate end mounts at both ends it would be rather solid and not move around. By then you'll be pissing around unless you have free access to a shear, break and material that $9 Grainger mount will look more attractive in cost, time and labor. Replace those bolts with all thread plus you will need to have vent holes drilled thru the end plates for motor cooling.
I recall speed control is for AC motors that have brushes not induction motors. A Milwaukee 1/2" drill motor or their industrial 1/4" porting tool grinder will run great off a POWERSTAT variable autotransformer, been using them for years doing porting work on single speed drill, grinders and porting tools. On induction motors they just layed down on torque and got hot. These autransformers are not cheap just have to get lucky at garage sales or penny markets. I'm lucky as I picked up 3 of them from 10 amp to 40 amp for $30 and almost brand new from a garage sale.
Keep an eye out for curbside trashed jogging machines as they have from 1 1/2 to 3 HP 90 volt DC ball bearing electric motors with a variable speed controller that corrects for constant rpm's with variable torque with a LED shutter that are high torque motors.
I picked up one across the street as the neighbor added a water bottle to the frame with self tapping screws that balled up and ripped apart half of the 24 wires of 22 gauge to the arrows up and down speed control plus other controls like heart rate at the top control panel. It was totally dead.
I stripped it apart and repaired the wiring it works i'll be damn. At app 400 rpm's you grab the flywheel (another great feature for grain motor use) it will slow down for less than a 1/2 second then you will feel the torque go way up, burn the glove as the LED speed controller is doing its job. I ripped apart a 2 year old $2,400 machine that looked like new but past warranty, wifey and kids wished I had it for a running again tread mill but I had grain mill motor plans. Talk about a wide rollered mill with cross hatched markings plus sealed ball bearings on 5/8" shafts as a super wide mill
of 22" x 1 7/8" diameter. This with a poly belt drive at 6.85 speed reduction.
The poly drive would take less belt tightening than a "V" belt preventing slipping with less mill bushing side loading if used as a motor / pulley only drive for your own grain mill. Think about it, a high torque constant speed motor no matter the load on it due to the speed controller plus you can vary the speed of your grain mill. Get lucky from a pissed off overweight person that gave up on running a tread mill available for free or cheap as to buy a 90 VDC motor and controller your past the 2-$300 price range. Sorry for the long NOVEL.
