# Changing the motor on a drill press



## Jack Wilson (Mar 14, 2010)

I have a Rikon radial benchtop drill press, it has a 1/3 hp 1720 rpm motor on it and I can easily stall it out, (and have several times)  . I am looking at a 1 hp 3450 rpm motor to replace it, but not sure about the speed increase, anybody know if I can reduce the rpm at the motor? At a minimum let me say that I am not a big fan of 1/3 hp motors, wish I had known how wussy it was before I bought it.


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## barking spider (Dec 26, 2010)

It would be much easier to just replace the motor with one that has the same rpm.
Otherwise, you will have to change to pulley sizes to compensate for the rpm increase.


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## Jack Wilson (Mar 14, 2010)

barking spider said:


> It would be much easier to just replace the motor with one that has the same rpm.
> Otherwise, you will have to change to pulley sizes to compensate for the rpm increase.


Ahhh yes, I thought about that, but the price is right! How is the speed determined? Is there an electrical solution, like remove this or that and the motor will slow down? (I don't mean remove the plug from the wall)! Or what about a rheostat, would that slow the motor but keep the hp?


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## RJM (Apr 11, 2010)

Jack Wilson said:


> Ahhh yes, I thought about that, but the price is right! How is the speed determined? Is there an electrical solution, like remove this or that and the motor will slow down? (I don't mean remove the plug from the wall)! Or what about a rheostat, would that slow the motor but keep the hp?


From you post, it's clear that both the old and new motors are induction motors. Electronic speed control for these requires a frequency control unit and, although they are less expensive now, they're still not cheap. It would be cheaper to buy the right motor.

A 1720 rpm motor has 4 poles whereas a 3450 rpm motor has 2. You cannot simply rewire anything; the construction is different.

You'll want to by a closed frame, fan cooled motor. The cheapest one I've seen is from Harbor Freight but you might be able to find something on Craig's list as well. Make sure the shaft will fit your pulley (these type/size motors always have a 5/8" shaft).

1 Horsepower Farm Duty Agricultural Motor


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## Cherryville Chuck (Sep 28, 2010)

Jack, the 3450 motor might work okay if you are only drilling wood. It will likely be too fast for metal except for small bits. Too fast tends to heat the metal up and work harden it in some cases and the extreme heat takes the temper out of the drill bits. It seems contrary to logic but you can drill metal faster at slower rpm than high rpm.


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## Jack Wilson (Mar 14, 2010)

Ok, ok, I'm starting to get the point. I'll keep my eyes open for a new motor that's running @ 1720. Robert, I didn't know all that stuff about motors, but I'll keep it all in a back room in my mind!


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