"dadiOH" wrote in :

Most disk sanders seem to be about 3500 rpm; at that speed, it is easy
to burn wood, need to have a light touch which is easy enough to do.
Still, I'd rather have one that is doing 1750 rpm; trouble is, they
charge more for them, no idea why.

More expensive to make a 1750 rpm motor. A motor with two
poles will turn at 3600 rpm on 60Hz AC line (unloaded, the
loaded speed will be around 3450 rpm). A motor with four
poles will run 1800 rpm (unloaded, around 1750 loaded).
None too surprisingly, it takes more material and effort
to make a 4-pole motor (altho not a whole lot more). So
2-pole motors are the most widely available and cheapest.

John