formula to calculate belt speed?

To figure the speed the belt is moving you need to know the diameter of the contact wheel, multiply that times 3.141592(pi) to get the circumference of the wheel. Then multiply that times the rpm of the motor. That will give you inches per minute. To figure feet per minute just divide by 12.

(diameter of wheel x pi) x rpm of motor = inches per minute
 
Shouldn't that be the diameter of the DRIVE WHEEL.
On some machines such as the BIII the contact wheel has nothing to do with generating belt speed , its just along for the ride so to speak.
What if there is step pullys and a belt betweened the motor and the grinder itself to make it a variable speed?
 
I should have been clearer.
I have a new Rob Frink grinder (tool gloat--highly recommended BTW), it has a motor pully, drive shaft pully and belt drive wheel on the drive shaft, all different diameters.
 
I think its the pully size on the motor over the pulley size on the grinder times the motor RPM, So if you have a 2" pulley on the motor and a 4" pulley on the grinder it would be 2/4 or.50 x 1725 or what ever your motor RPMs are in this case belt speed would be 862.5
I think this is right, but I wouldn't bet the farm on it.:confused:

Bill
 
Mr Buxton, I beleave you are right, mostly

that will give you the RPMs of the contact wheel. you still have to use L6's formula to change the RPMs of contact wheel to feet per second of belt travel.
 
Eric,

Do you mean, that now that I have the contact wheel speed, I have to multiply 3.14 times my contact wheel diameter which is 10", and that total times the figured speed which is 862.5. That would be 3.14 x 10 = 31.4 x 862.5 = 27082.5 inches or 2256.8 ft. per minute. Doesn't that seem awful fast, or did I miss something??:confused:

This is hurting my brain and I smell smoke.:D :D

Bill
 
You guys are right, it's the drive wheel. I was thinking of a Grizzly for some reason.
 
Hey Guys,

Here is how I do it on the KMG1. The drive wheel is 4" in diameter which is about 1 foot in circumference 4XPI=12.56". That means the belt travles 1 ft per turn of the drive wheel. So to find the belt speed on the KMG1, it is simple the drive shaft RPM. If the drive shaft is turning 3600 rpm, then the belt is moving 3600 ft/min....500 rpm=500ft/min and so on...

Knowing this for a 4" drive wheel, then an 8" DRIVE wheel would be 2X the 4" speeds. So for a grizzly with an 8" drive wheel/contact wheel...the motor spins 1725rpm hence the belt speed is about 2X 1725 =3500 ft/min.

Note that I rounded PI from 3.141... to 3.0. That makes it easy to do in my head. There is about a 5% error but that is plently close enough for me.

;) Rob
 
Pi R squared x the length of the belt x speed of motor divided by how much of the pie you ate!!!!!!!!!!! :)
:p
 
Tom, why do you use pi r squared?

Pi r round,

did you eat the crust off?

yes Bill that is right. but it should be drive wheel, not contact wheel like L-6 said:D

that belt moves fast dont it
 
Pi R squared? I don't think so!

Cornbread R squared!

Not Funny?

OK, stop yelling.
 
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