This is my first post so bear with me. I realize that this is not about the router but it is about woodworking. I recently upgraded my Delta tablesaw. I went to a 2hp 220ah motor. My drive pully ( the one on the motor) is 4" and the one on the blade shaft is 2.5" the rpm is 3640, and as the best I can tell the surface ft per minute is 9524.6 I am used to a 1hp and the new motor turns a lot faster as can be expected. My question is how fast is to fast?. Do you guys think that the above numbers are safe. tks in advance
As was already pointed out, you don not need to calculate SFM for your blade since all saw blades give max speed in RPM. That said, I'm guessing you bought the wrong motor. If the new 2HP motor is about the same size (or a little bigger) than the 1 HP, then you probably replaced a 1HP, 4 pole motor with a 2HP, 2 pole motor; doubling the motor speed in the process.
I'm don't know where the 3640 RPM figure is from. A 2 pole motor has a maximum sychronous speed of 3600 rpm on 60Hz power. True max speed is probably closer to 3450 rpm (5% slip). Anyway, using the 3600 number with your pulleys, this comes out to 5760 rpm (actual max will be closer to 5530 rpm), so, for a 6000 rpm max speed saw blade, this should be okay.
On the other hand, you've doubled the speed of your blade. I don't know how this will affect cutting wood but it will. I've read that you should not do this (TABLESAW TUNE
). Also, you've doubled the HP but also the speed, so the torque at the blade will be about the same as with the 1 HP motor, so it may not perform that well anyway.
Solution: Buy a 2.0" diameter pulley for the motor (you probably have a 5/8" motor shaft)
. This will cut the blade speed in half. You'll need a different size v-belt too. You can try one of those adjustable link belts
, or if you know (or can measure) the center distance between the shafts, you might be able to calculate the size of the belt you need.