Bandsaw power upgrade

[Curt Taylor]

Greetings
I'm looking to uprade the motor on my 14" Delta BS. It currently has the stock 1/2hp motor running stock pulleys. Drive=2" and the other is 6". I'd like to use a 3/4hpGE totally enclosed motor I have laying around. Problem is the GE is 3450 and the stock motor is 1175. Does anyone know what the pully changes would have to be to make this work or would this be unrealistic to even try.

[Pete Bradley]

I would have expected the stock motor to be 1725, it's worth double checking.

Google up bandsaw pulley speed formula. Your motor pulley is about as small as it can go so you'd have to switch to a 12" pulley at the wheel assuming your current motor is a 1725.

Pete

[Eddie Darby]

14" Bandsaw at 1175 RPM with 2" and 6" pulleys gives 1435.5 sfpm. (surface feet per minute)

This is on the low end, and is good for cutting thick hardwoods without burning problems. Most 2 speed bandsaws come with a speed of 1500 and 3000 sfpm.

If you do upgrade to a 1725 RPM motor, and keep the same pulleys then you will have a speed of 2107.5 sfpm.

The top end of a 14" bandsaw speed is around 3200 sfpm, so you can play around with the pulleys to get the speed you want. The problem is that the faster speed comes with more risk of burning thick hardwoods, but is good for cutting green wood that is thick.

3" and 6" at 1725 RPM gives 3161 sfpm.

3450 RPM with your present pulleys will be way too fast at 4215 sfpm.

3450 RPM with 2" and 8" pulleys gives 3161 sfpm, as does 1.75" and 7". You may need to build a new housing for the larger pulley.

To go from a 1/2 hp to a 3/4 hp will not be very noticeable, so I would be looking for something bigger and save the 3/4 hp for something else.

http://www.woodturnerruss.com/Bandsaw-Tuning.html

http://www.woodturnerruss.com/Bandsaw-Using.html

Both links worth the read.

[Bart Leetch]

I went from a 3/4 HP 1725 RPM motor & a 3" & 6" pulleys on my Grizzly 14" Band-saw to a 1 1/2 HP 1725 RPM motor & the same pulleys & it made a world of difference. The 3/4 HP motor should be a 1725 RPM with the same pulleys but you won't notice much difference in power.

[Eddie Darby]

Nice pics!

Do you think there is a difference between pulley sets of 3" and 6" vs. 2" and 4"?

I have 2" and 4" right now.

[Bart Leetch]

Nice pics!

Do you think there is a difference between pulley sets of 3" and 6" vs. 2" and 4"?

I have 2" and 4" right now.

On a 1725 motor with a 3/6 combination the final RPM I believe would be 862.5

For a 2/4 combination it would be 862.5 RPM. With the 3450 RPM motor with the 2/4 combination would be 1725 RPM final drive. You need a slower motor or a 2/8 combination final drive would be 862.5 RPM. What I don't know is how this would affect the power.

Hope this helps.

[Wilbur Pan]

Nice pics!

Do you think there is a difference between pulley sets of 3" and 6" vs. 2" and 4"?

I have 2" and 4" right now.

Either set will give you the same final blade speed, all other things being equal.

However, using smaller pulleys will put more stress on the drive belt since it makes a tighter turn to get around the pulleys. It may put more stress on the motor, but I'm not sure about that. I'm not sure if this means anything in the long run, but after I worked out the correct pulley diameter ratio, I put the biggest pulleys I could get that met this ratio on my bandsaw when I was swapping out pulleys to adjust the blade speed.

[Eddie Darby]

My housing for the upper wheel is 7" in width, so I can get a bigger pulley in there if need be.

I'm using link-belt so I think the tighter radius turn isn't as much of a problem.
I am thinking that the torque might be better. Also the extra mass of a bigger wheel should help with added momentum.

[David Freed]

There are pulley sizes and motor speeds being talked about that you did not mention. Everyone is using the right formula to calculate, but they aren't using your numbers in the equation. If your motor speed is actually 1175 rpm as you stated (I am assuming you read the tag right), and you keep the 2" drive pulley (smaller than that is not practical), then you would need an 18" driven pulley to keep your blade speed the same.

3450 / 1175 = 2.936 (round that up to 3 for convenience sake). 3 x 6" (original driven pulley size) = 18" (new driven pulley size).

I doubt if you could find a pulley that large to fit your shaft size, let alone fit inside your blade guard. I would look for a larger motor (1 to 1 1/2 hp) with the same rpm's as your original. Even if you would get a motor that runs at 1725 rpm's, you would need a 9" driven pulley to keep your blade speed the same, and that probably wouldn't fit inside your blade guard either.

After rereading Eddie's post I see he was using your numbers, and giving you different speeds to look at. I was trying to keep you at the same speed.