Bandsaw Blade Speeds and Pulley Ratios

Figuring out how to adapt a motor to an old bandsaw. December 9, 2010

Question
I have an old band saw (Babbitt bearings) that I would like to get running. The saw is in great shape but it needs a motor. I have a 3450 rpm motor that I would like to use but I think that it will be too fast. I can't find the book that I know I have somewhere that has the formulas I need but from memory I calculated a blade speed of1805 fpm blade speed. I have a two inch pulley on the motor and a 12 inch pulley on the saw. The saw has 20 inch wheels. Does that number seem right? Also, what should the blade speed be?

Forum Responses
(Solid Wood Machining Forum)
From contributor J:
If I remember correctly, you want to be between 700-800 fpm. You'd be good with a 1725 motor I think. I had a 30" saw, 4" pulley on the motor, and 12" on the saw with a 1725 rpm 5 hp Baldor. It ran great.


From contributor A:
Bandsaws always use 1725 rpm. The 3450 rpm are way too fast.

From contributor R:
Depending on the size of the wheels bandsaw blade speeds can vary between 2000 SFPM to over 4500 SFPM. In the case of a 20" bandsaw I would shoot for something in the 3000-4000 SFPM range.

From the original questioner:
Thanks to all who answered. I have it running and found the formulas I was looking for. The speed seems about right but I think a slower motor with a bigger motor pulley might give the saw more torque.

From contributor R:
Your assessment of a slower motor with different pulleys would yield more torque is correct. You should have twice as much torque with a 1725 rpm motor than 3450 after you adjusted for the speed difference using pulleys.

If it were my saw I would look for a 2-3 hp 3 phase motor and power it with a VFD. It should be about the same cost as a single phase motor. It will give you better control over the speed of the blade.

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