Not the usual step pulley question

J

Jason Fry

Joined
Jun 5, 2008
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Working on a NWG, figuring on what pulleys to order. I have a 1 HP 3400RPM motor. I know the math, etc. on how to figure out my RPM's and SFPM.

Here's where I lose it...
Most folks go with a 2-3-4 on the motor and 4-3-2 on the drive shaft. This gives you 2x, 1x, .5x RPM outputs. With my motor, that's 6800 (WAY too fast), 3400, and 1700 RPM.

Is there any reason you couldn't use a 2-2-2 pulley on the motor and a 4-3-2 on the drive shaft? That way you could get 1x, .5x, and .25x RPM outputs. With my motor, that would be 3400, 1700, and 850 RPM, which with a 4" drive wheel translates into roughly the same SFPM.

Belt tension will be from a hinged motor base plate, if that makes a difference.
 
The visual is screwing with my brain at the moment...but have the same diameter pulley's on the on the motor and 3 different diameter's on the drive shaft pulley would require either the motor to move, or the use of three different length belts.....no?

edit: Ohhh, you're going to make the hinge compensate for this?!?!? I'm stupid!! :) Carry on and ignore me!
 
Just use a sliding hinge with a single 2" on the motor. Someone put up a description and pictures of a simple one on here, I'll see if I can dig it up.


-Xander
 
6800 is not too fast for good ceramic belts. They are built for these speeds. I run 5400 with a 3 horse motor and would like that other 1000 sfm.
 
Fred.Rowe said:
6800 is not too fast for good ceramic belts. They are built for these speeds. I run 5400 with a 3 horse motor and would like that other 1000 sfm.
Click to expand...

Why not buy a new smaller pulley for the drive shaft to gain the wanted speed?
 
PT Doc said:
Why not buy a new smaller pulley for the drive shaft to gain the wanted speed?
Click to expand...

This machine is set up with a 2x3x4 pulley system and a 6 inch drive wheel. Even though I could use the extra spm the 5400 is adequate for now. I'm working on an anodizing set up along with a vibrator tumbler that I hope to have up and running by late fall.
I do have a friend down south who runs a 5 hp motor and 7000 sfm grinder. He uses a jig and lever system to grind blades. The sparks are amazing to watch.

Fred
 
Fred.Rowe said:
This machine is set up with a 2x3x4 pulley system and a 6 inch drive wheel. Even though I could use the extra spm the 5400 is adequate for now. I'm working on an anodizing set up along with a vibrator tumbler that I hope to have up and running by late fall.
I do have a friend down south who runs a 5 hp motor and 7000 sfm grinder. He uses a jig and lever system to grind blades. The sparks are amazing to watch.

Fred
Click to expand...

No that sounds like it would be really fun to watch him grind.
 
+1! Can you get him to do a video, or ask him if I can contact him? I have some specific questions for him. My email is turned on through the forum.
 
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