3 step pulleys and ginder motor questions

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Dixieblade57

Joined
Jun 20, 2007
Messages
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I am putting together all the componets for my KMG clone grinder build. Here is the question that has poped up in my mind and since I have never had any experince here, I have to ask these questions.
The motor I am looking at is a 2 HP TEFC 1 Phase Electric Motor 56HZ 7/8, Speed/RPM: 1725

1. Am I correct in my understanding that you have to have the 3 step pulleys on both motor and drive shaft for the grinder, and they are tuned in reverse of each other (like on my drill press) to be able to obtain a variable speed setup?

2. Will I need to run a 4" 3" 2" step on both motor and drive shaft or will one of them need to be different size on the steps?

3. Does someone have a scematic for the various speeds that can be attained! Or is there a formula for figureing it out using a 4" 3" 2" step pulley on both the motor and drive shaft

Any light you can shed by some of you that are running the step pulley set up would be appreciated!!!!!:confused:
 
1. Yes
2. They should be the same.
3. The speeds are determined by taking the motor side divided by the drive shaft side, times the motor speed. That is for RPMs, not SFM (Surface feet per min)

SFM = RPM x Diameter of drive wheel x 0.262

Your RPM speeds would be 3450, 1725, and 862.5
 
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On my No Weld Grinder I have 2 3 step pulleys. The one on the Motor has the small pulley close to the motor. The other pulley is reversed. With the belt on the small motor pulley and the large pulley on the drive wheel it goes nice and slow. With the belt on the motors large pulley and small one on the drive pulley it's pretty fast. Belt speeds I can't help with. Works for me. My Motor is 1725 rpm also.
 
go mike said:
1. Yes
2. They should be the same.
3. The speeds are determined by taking the motor side divided by the drive shaft side, times the motor speed. That is for RPMs, not SFM (Surface feet per min)

SFM = RPM x Diameter of drive wheel x 0.262

Your RPM speeds would be 3450, 1725, and 862.5
Click to expand...

Thanks Mike that is just what I was looking for, thanks again!:thumbup:

I know to some these questions sound dumb but, if you don't ask you don't never learn!
 
i have a 3 step on my motor and an adjustable pulley on my driven shaft. you can fine tune the speeds a lot more with this setup.
 
go mike said:
1. Yes
2. They should be the same.
3. The speeds are determined by taking the motor side divided by the drive shaft side, times the motor speed. That is for RPMs, not SFM (Surface feet per min)

SFM = RPM x Diameter of drive wheel x 0.262

Your RPM speeds would be 3450, 1725, and 862.5
Click to expand...

Using your formula Mike SFM = RPM x Diameter of drive wheel x 0.262
and the RPM of 1725 and a 4" drive wheel you are looking at 1808 SFM
Same RPM of 1725 and a 6" drive wheel you are looking at 2712 SFM
So that means the larger the drive wheel the higher the speed, correct? Is my math and my assumption correct? I guess what I am saying is with that 2hp. motor a 4" drive wheel should be sufficient, correct?

richard j said:
i have a 3 step on my motor and an adjustable pulley on my driven shaft. you can fine tune the speeds a lot more with this setup.
Click to expand...

Richard got any pics of this adjustable pulley? Where did you get it? I have never heard of an adjustable pulley but find the idea "very interesting"! :cool:

Email sent
 
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Dixieblade57 said:
Using your formula Mike SFM = RPM x Diameter of drive wheel x 0.262
and the RPM of 1725 and a 4" drive wheel you are looking at 1808 SFM
Same RPM of 1725 and a 6" drive wheel you are looking at 2712 SFM
So that means the larger the drive wheel the higher the speed, correct? Is my math and my assumption correct? I guess what I am saying is with that 2hp. motor a 4" drive wheel should be sufficient, correct?
Click to expand...

Yes, your math is correct, and a 4" drive wheel should be sufficient.
 
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