Hello to all and my first question...

A

AmericanPinto

Joined
Jun 23, 2011
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Hello to all from Pinto. Im from New Mexico and just getting started at knife making. I am currently redoing my small shop to set up for all the tools I will be using. I am looking at purchasing the KMG grinder possibly monday; however, I am on the fence as what to do about motor selection. My budget will allow me to choose the 1.5 hp with the step down pulleys from KMG but....I do have a 1.5hp motor I inherited from my father. The only thing is...the motor is 3450 RPM motor. I am wondering if that is to fast even if I buy step down pulleys. I see KMG's motor is 1725 RPM and the step down pulleys would slow it down even more. I am assuming a 3450 RPm motor might not slow down enough?
 
If you use it as a direct drive, you wont be able to slow it down without variable control. Wth step pullies, you will need to have a small wheel on the motor and a wheel at least double the size on the grinder in order to give you 1725 rpm. Im not sure what the fastest a KMG can go safely but probably not more than 2000. So if you have a 2" wheel on your motor, you will need a 4" on your grinder. if you can find a 1" you might be better off, then you can put on a step set which could have 2/3/4" wheels giving you 1725/1150/860 rpm respectively.
 
Thanks for the information. I'll talk with Rob on Monday and see what he recommends as well. If I can arrange for this motor to be used, it will save 318 bucks!
 
hmm I'm also thinking that the 6 inch drive wheel option on the grinder might slow it down too....then I could use the standard 2,3,4 inch step pulleys that he sells with the package.
 
Good thinking about putting the step pulleys on the motor and a single large pulley on the KMG. The sizes you state will work well.

Mount the motor on a base board and use a piece of pipe or round stock to make a hinge. The board can then be slid from side to side to align the pulleys. The weight of the motor should be enough for tension, or a spring/bungee can be used if more tension is needed.

All that said, is the motor the right type?
You will need a TEFC motor. Most 3450 motors I come across are open cased. Such motors will burn out pretty fast on a grinder. If there are vents and slots for the air to flow through the motor, the metal dust will get in and cause problems.
 
I have used a drip proof for the last year and a half, which has vents as Stacy says. I have it covered but I also vacuum it regularly depending on use. I have fried a motor before by filling it with grinder dust and not cleaning it. Those sparks make for an exciting day :-)
 
I know Count, I was just referring to post #5 in this very thread.

There seems to be 2 threads going about the same issue...
 
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