Speed problem with circular saw...need advice

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Forum topic by lionel1020 posted 09-21-2015 10:38 PM 753 views 0 times favorited 4 replies Add to Favorites Watch
View lionel1020's profile


2 posts in 1177 days

09-21-2015 10:38 PM

Hi everyone,

I was given a circular saw…fairly old model. As I already have a very good saw I thought I would change this one into a disk sander. The conversion was fairly simple, building a mounting and changing the saw blade into a “backplate” for a circular wooden bed on which to stick the sandpaper. In short everything works.

However…....when I turned it on it goes fast… so fast it’s downright frightening….it really is fast.

So how can I reduce the speed?...... reduce the voltage?

It’s plugged in to the mains…

Any ideas; comments, advice would be most welcome…


4 replies so far

View CharleyL's profile


223 posts in 3563 days

#1 posted 09-22-2015 12:03 AM

That is a very dangerous way to make a sander. A circular saw spins way too fast to make a good sander, and your “disk” may fly apart at that speed causing serious injury or death to anyone that the pieces hit.

If the saw motor is listed on the identification plate as “AC-DC” or “Universal” a router speed control can be used to adjust and reduce the speed. However, reducing the speed will also reduce the power, and if you slow it down too much there won’t be enough air circulation through the motor to keep it cool. I think you should abandon this crazy idea and look for safer ways to make a sander.


View BurlyBob's profile


5977 posts in 2464 days

#2 posted 09-22-2015 02:05 AM

I’m thinking you should listen to Charlely!!! He makes a lot of common sense. Since it was a free saw your out nothing. Charley could be saving you from a trip to the ER.

View lionel1020's profile


2 posts in 1177 days

#3 posted 09-22-2015 07:15 AM

Thanks for the comments Charley, Bob…..I rather thought this would be the consensus opinion.
I’ll take it apart and think of something else…..
Thanks again

View dhazelton's profile


2793 posts in 2496 days

#4 posted 09-22-2015 11:34 AM

Use the motor but drive your sanding disc with pulleys. Smaller one on motor, bigger one on disc. But then you’re talking about adding a pillow block and bearings. Unless you have that stuff sitting around you may as well buy a sander.

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