Saturday, December 19, 2020

Turning A Blower Motor Into A Grinder

... will depend on the torque produced by the motor. That is, will the motor be able to spin a sharpening disc while I put resistance on it in the form of a knife pressed against the disc?

Cleaning out my parents' house for the very last time, I came across a spare blower motor from their cooktop hood. My dad being who he was, the thing was in working order and properly labeled.

The model number actually refers to the cooktop hood, not the motor itself.

The wiring connectors are .093" Molex pins, which I have a-plenty from my MGB rewiring project. I applied some AC power to the pins, guessing at the color code, and the motor turned nicely. Excellent! I now have that magical creature from the start of the Industrial Revolution, a device for turning a shaft.

Excel, as they say, sior.

I know I could simply scrounge around and find a grinding wheel and affix it to the shaft in some way, but that would take away all the science. As a ignorant and superstitious orthodox Catholic, I feel it is my responsibility to study science as much as possible in order to discover a way to destroy it for the Papacy.

I digress.

Torque is measured in pound-feet (corrected, thanks to the comment of Mostly Nothing, below) and is radius times weight as shown in the video below. Now what I need is a mount for the motor, a wheel of known radius on the shaft, a rope, a pulley and a set of weights to lift.

Once I know how much torque it produces, I can attach the grinding wheel and find out if it works for sharpening knives. My torque experiments might be of no practical value, but at least my head will be filled with delightful numbers and equations while I ruin my kitchen knives.


Mostly Nothing said...

pound / feet not foot-pounds.

I have this, and I didn't pay near that price. Works great.

And a bench grinder is cheaper still.

I know, this is an intellectual process not a getting things done adventure.

I thought you were getting this out for the cotton gin?

K T Cat said...

I'd like to attach it to my cotton gin, but I'm still occupied with creating gears that don't work.