Grizzly lathe grinder.

[Flyinfool]

That sure looks a LOT more elegant than my tool post grinder.

Out of curiosity, why convert to DC?
Yes a universal motor will run on DC, but the Positive carbon brush will wear extremely fast, and it is also very hard on the commutator. The motor also will not run as efficiently, not just amp draw, but it will run hotter and slower and make less power.
You would be much better off running a plain old switch and feeding the motor the AC it was designed for.

The drill motor was designed to run on DC so it was fine.

To help save the carbon brushes, add a DPDT reversing switch so that every time you use the grinder the polarity of the power gets reversed, this only helps with the positive brush wear issue all of the rest of the issues will still be there.

 

[big o]

That sure looks a LOT more elegant than my tool post grinder.

Out of curiosity, why convert to DC?
Yes a universal motor will run on DC, but the Positive carbon brush will wear extremely fast, and it is also very hard on the commutator. The motor also will not run as efficiently, not just amp draw, but it will run hotter and slower and make less power.
You would be much better off running a plain old switch and feeding the motor the AC it was designed for.

The drill motor was designed to run on DC so it was fine.

To help save the carbon brushes, add a DPDT reversing switch so that every time you use the grinder the polarity of the power gets reversed, this only helps with the positive brush wear issue all of the rest of the issues will still be there.

Converted to DC since I had a pistol grip drill switch, which controls speed thru a bridge rectifier, changing AC to DC.
Didn't use the reverse part of the switch, not enough room in box.

 

[big o]

Converted to DC since I had a pistol grip drill switch, which controls speed thru a bridge rectifier, changing AC to DC. Didn't use the
reverse part of the switch, not enough room in box.