Bandsaw speed

[Jerry Bittner]

Have to get a new motor for my ancient Delta 12" bandsaw. The pulley on the bandsaw is 6' diameter. I realize the diameter of the new motor pulley will have to be sized to relate to the bandsaw
so what should be the speed of the bandsaw?

[John Lanciani]

I set up my 10" Delta to run at about 2200 fpm and my 14" at about 2800 fpm (My 20" saw runs at 5000 fpm). The 10" has glued rubber tires and the 14" has urethane tires with no glue. Both use 1725 rpm motors, I don't remember the sheave size on either off the top of my head but there are plenty of calculators available on the web.

[Gary Radice]

Is it a 12 inch? I thought older Deltas were either 10 or 14 inch, but I might be wrong about that. Got a model #?
Also, vintagemachinery.org may have manual and parts list for you.

[John McClanahan]

My 12" Craftsman runs at about 2800 fpm. It has a 3/4 hp motor.

John

[Benjamin Miller]

Most bandsaw blades cut wood best around 3000 fpm.


Doing some simple algebra:
12" / 6" = 2 (multiplier for top wheel, because circumference and diameter are linearly related)


d is motor pulley diameter
3000 fpm = 36000 ipm
36000 = 3.14 * d * 2 * rpm


With 1750 rpm:
d = 36000 / (3.14 * 2 * 1750)
d = 3.3"


With 3500 rpm:
d = 36000 / (3.14 * 2 * 3500)
d = 1.6"


As you can see, with the 3500 rpm motor, you're getting to a pretty tiny pulley. Smaller pulleys are less efficient and can transmit less torque, so I would install a 1750 rpm motor and a 3.5" pulley.


If you want to get really fancy, use a 3 phase motor and VFD so that you can slow down your saw to cut other materials like metals.

[Myk Rian]

What motor is in it now?
1725 is a usual rpm. Hp is up to you, but more than 3/4hp is over doing it on a 12" saw.

[Jim Rimmer]

Most bandsaw blades cut wood best around 3000 fpm.


Doing some simple algebra:
12" / 6" = 2 (multiplier for top wheel, because circumference and diameter are linearly related)


d is motor pulley diameter
3000 fpm = 36000 ipm
36000 = 3.14 * d * 2 * rpm


With 1750 rpm:
d = 36000 / (3.14 * 2 * 1750)
d = 3.3"


With 3500 rpm:
d = 36000 / (3.14 * 2 * 3500)
d = 1.6"


As you can see, with the 3500 rpm motor, you're getting to a pretty tiny pulley. Smaller pulleys are less efficient and can transmit less torque, so I would install a 1750 rpm motor and a 3.5" pulley.


If you want to get really fancy, use a 3 phase motor and VFD so that you can slow down your saw to cut other materials like metals.

But he said 6 feet in diameter.

[Jerry Bittner]

Thanks everyone. I found a site that all you do is plug in the particulars and it gives you the fpm-- mine ended up at 2800