Thread: grinder build motor question

Originally Posted by Substance

How about a washing machine motor Adam any options there?

Afaik, washing machine motors don't have enough power.

Thankyou All.
Really appreciate the info. Slow it is.
Regards,

DC motor with a controller. You can run it from barely turning to SMOKING fast. You can even reverse it if the controller is set up right.

After fighting belts and pulleys on mine, I'm going the DC motor route. Buddy of mine is a wizard that works on mail sorting machines and has a pile of motors. He's gonna rig my 2"X72" belt grinder up for me.

Originally Posted by Wullie

DC motor with a controller. You can run it from barely turning to SMOKING fast. You can even reverse it if the controller is set up right.

After fighting belts and pulleys on mine, I'm going the DC motor route. Buddy of mine is a wizard that works on mail sorting machines and has a pile of motors. He's gonna rig my 2"X72" belt grinder up for me.

Will be cool to have one that separates the hollow grinds from the wedges and sets them in the right boxes when finished :<0)

Make sure your motor is a "sealed" design. Most treadmill motors are not, and will fail eventually from metal dust getting into the guts of the motor. I had one when I first set up my grinder - lasted about two years until it fried.

Originally Posted by Adam G.

Hi All,well, for those of you who have followed my grinder build, the pool pump motor did not work out. The spindle is too thin and the fitter and turners i asked for help after i failed to extend and thicken it successfully, advised against it. They are sure the spindle would break under the lateral force of the drive bulit at some point soon while grinding - not a fun thing to have happen. least it was free.Sooo... i have looked about and not found anything i liked in the junkers, so am now looking to buy a motor.In Australia we have 240volt power, and i only have access to single phase, and variable speeds here are prohibitively expensive, so this helped narrow my choices. i have found some 2HP motors i am happy with. Two options to choose from. One runs at 1440rpm and the other at 2800rpm. i am using a 4 step pulley set up with a 5 inch diameter on the largest step. 2x72 belts. My gut says the slower speed is the better - more control, and excellent on the slowest step pulley for polishing. High speeds chew steel, but also make it really easy to stuff a blade right up in a spilt second.So - anyone who has built or uses ready made grinders regularly, please chime in with your thoughts. Is my logic flawed? Will the slower rpm be too slow to get the work done reasonably quickly?Appreciate your feedback.

Slower speed also means more torque for an AC motor. The 1440rpm motor would have 4 poles and the 2800rpm motor would have 2 poles. Even though they have the same hp rating the slower motor would have more torque and be harder to stall at it's rated speed. Of course, changing the grinder speed with pulleys would effect toque as well, but in general you will get more low end grunt from the slower motor.