Gear Motor For Charcoal Grinder

I am looking to build a charcoal grinder/processing station and want to find a gear motor to drive the whole thing. Does anyone have advice as to where I should look to find an appropriate motor? From what I have seen in some other threads, some people are using pretty small motors (1/20 - 1/25 HP) with some gears to achieve an RPM range appropriate to slowly spinning the grinder. Does anyone have specific models or specs for a motor? I am looking to find something that runs on 12 or 24 volts. Thanks.

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I just use pulleys to gear mine down. You could also use sprockets and chains. By the way I use a denso electric power steering motor from a Chevy HHR, I work at a GM Dealership and when they recalled them, a lot of them still worked. It’s 12vdc.

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I used a hand drill with variable speed. I had a plug in drill but you could use a battery powered on. TomC

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Handy Andy on here used a gearbox from an old tiller and some pulleys to achieve a good grinding speed. He demonstrated his grinder and sorting screen at Argos before. I think there is a video of it in some of the old Argos videos.

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Surplus center has gear reduction motors.

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Thanks for the feedback, guys.

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Windshield wiper assemblies are an easy/cheap source for a 12v gear motor. Extra cheap from a junk yard.

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The best by a mile is a disabled wheel chair drive motor and gearbox , i have had one very crudely bolted onto my wood chipper/shredder for 8 years and its sat out in all weathers and never misses a beat , runs off 12 volt or if i want to speed it up then 24 volts as well so much torque never stopped the motor in all that time , maybe a belt slip is all .
Dave

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Recently I was looking though some pictures and videos I took at Argos 2019 and found a video where I got really good close up look at Andy’s charcoal grinder.

Wow! After a little research, it looks like wheelchair motors seem to be a great option. Used they are inexpensive and they seem very robust.

The mobility scooters are easier to find, and use the same motors, but only 1 instead of 2. They both have automatic brakes on them, that engage if there is no power to the circuit to keep it from rolling, that unless you want to wire something to disable the brake, most people just remove the brake pads/circuit.
All the ones I have, have brushes. If you get the whole scooter, you have to keep the whole group of electronics in tact. They have safety stuff all over the place in them like circuit protection for not being plugged into a charger

A drier motor might be better.

If you want a cheaper gearbox, snowblowers have like a 10:1 reduction gear for the augers. garage door openers usually have a universal motor, that can overheat fairly quickly, but they usually have a worm gear drive as well. The cost of gear reduction is usually more then the cost of the motor. but it also doesn’t have to be anything fancy. a hole drilled through wood with grease on it, will work for quite a while as long as it isn’t superfast.

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If you want brushless it is tough to beat a brushless hand drill. 18v/21v models could probably handle 24 volts DC from a power supply for a little extra power. ~$100-150 brand new. The most powerful models have similar watt ratings as a scooter motor.

Low speed on a drill is still 400-600 RPM though (10 revs per second’ish). Maybe too fast for a grinder without further gearing.

You can usually find them cheap used because the battery packs die and people want to upgrade rather then buy a new battery pack or fix the one they have. The nutdriver ones are geared a lot lower like 6x slower which takes care of some of the issue. Then you can directly wire it from a battery pack using a buck or boost converter to get the right voltage. usually they allow like 10% overvoltage for electronics, so 24v is over that limit so it will probably work but it will most likely overheat and die if it runs for a long time.

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