Thread: Calling all electric motor experts........

The HP is ok and so is the motor shaft size. The speed is quite fast but step down pulleys will be necessary. What you need is a larger pulley on the grinder drive shaft and a smaller one on the motor shaft. Pulleys for the 5/8" shaft size can be a 2-3 or 4 step. The smallest beginning size step is 2", which you would want on the motor shaft. You want a 3" initial step size on the grinder drive shaft or larger. With the speed of that motor I would use a 4 step pulley system. The small pulley should be a 2-3-4-5" and the large pulley a 3-4-5-6"

Pay attention to the direction of rotation on the motor. You will want a CCW ( counter clockwise) rotation.

The groove in the shaft is called a "keyway". The pulleys will also have this. A 3/16" square, 1" long piece of mild steel is placed in the keyways to lock everything together. The pulleys should also have a set screw built in. This screws down onto the "key". I sould have my grinders here at home in a week or two. Stop by and look them over if you want to. Building them is a bit of a learning curve.

Boy, Randy, sounds like you've been thinking about this a bit lately... Well stated.

Josh

The other major determinant of belt speed is the diameter of the belt drive wheel. Most use a 4" wheel in conjunction with a 1750 RPM motor. If that wheel size is reduced to 2" then the drive speed will be reduced by 50%. So maybe a 2" drive wheel would be the easiest way to go? Don't ask me where to get a 2" drive wheel, I don't know. Maybe Tracy Mickley does? or Rob Frink?

Originally Posted by randydance062449

The other major determinant of belt speed is the diameter of the belt drive wheel. Most use a 4" wheel in conjunction with a 1750 RPM motor. If that wheel size is reduced to 2" then the drive speed will be reduced by 50%. So maybe a 2" drive wheel would be the easiest way to go? Don't ask me where to get a 2" drive wheel, I don't know. Maybe Tracy Mickley does? or Rob Frink?

Thanks for the great advice, Randy. I'll have to swing by sometime when a get a chance and see your grinders. The idea with this motor and building a grinder for myself is that the motor has never been used NOS and it was free. That said, if retrofitting this motor to make a great grinder is going to cost as much as getting a good 1750 rpm motor and twice the challenge (or hassle), then nothing lost nothing gained. I'll have to look into small drive wheels and email Tracy Mickley whom I see is also a fellow Minnesotan.

Thanks again.

Chris L

Hello Chris,

I can see how this may be giving you a sense that the motor is not worth the hassle. This is not the case. Tracy Mickley can call Rob Frink, (tracy buys his wheels from Rob) Rob can say yes or no to the 2" drive wheel. If yes, then everything becomes easy and normal. You would use the 3 step pulleys from Tracy and all will be solved. If no, then you have to jump thru some hoops to get the right pulleys for the speed reduction you are looking for.

Just one step at a time,

Originally Posted by randydance062449

Hello Chris,

I can see how this may be giving you a sense that the motor is not worth the hassle. This is not the case. Tracy Mickley can call Rob Frink, (tracy buys his wheels from Rob) Rob can say yes or no to the 2" drive wheel. If yes, then everything becomes easy and normal. You would use the 3 step pulleys from Tracy and all will be solved. If no, then you have to jump thru some hoops to get the right pulleys for the speed reduction you are looking for.

Just one step at a time,

Very cool, Randy. Thanks for the reassurance and the very wise advice ("Just one step at a time"). I'll get in contact with Tracy soon and keep you posted.

Chris L

A free 2 hp motor is nothing to sneeze at. Even a low-end 2 hp motor would probably run $150 or $200. I spent more than $100 on my 1 hp, and it's just a Grizzly motor. The two biggest expenses in building a grinder are the motor and the various wheels, especially the contact wheels.

Josh

Out of croisity do you ever use the hardware on your straights?

Originally Posted by JoshEarl

A free 2 hp motor is nothing to sneeze at. Even a low-end 2 hp motor would probably run $150 or $200. I spent more than $100 on my 1 hp, and it's just a Grizzly motor. The two biggest expenses in building a grinder are the motor and the various wheels, especially the contact wheels.

Josh

On the contact wheels I've heard tell that it's possible to use polyurethane coated castors as a cheap alternative - what are your thoughts on this ?

Barney

Shhhh... Don't let that secret out.

My 8" contact wheel came off a forklift pallet jack. Free. I got a 6" wheel on eBay for about $10 plus shipping. I got a 10" wheel for the same price.

You have to get them turned true at a machine shop, which cost me less than $50 per wheel. You could probably do better, but I live in a snooty residential area that doesn't countanance dirty stuff like junkyards and machine shops.

They work very, very well. Could a $300, precision-machined wheel do better? Probably, but I don't know that my blades will know the difference until I've had a few more years' practice.

Josh