Building a grinder

[Pairomedicsfish]

Any thoughts on using a treadmill motor and controlls to run a grinder?

[Ray Rogers]

Yes, don't. The treadmill motors I have seen are very small. I tested the electronics on the DC motors I had and managed to burn them out without much effort. I've heard of people trying treadmill motors on their grinders before but never heard any glowing reports of the results. So, I'm not sure I have any really concrete reasons not to do it but my gut says it might work but probably not well and not for long ....

[mperez76er]

no but this is what i built. http://www.metalwebnews.com/manuals/knife-grinder.pdf it has all the pics and specs. take your time and invest. i cut some corners and did some mods. i built it on a budjet and out of scrap steel but in the near future will build it corectly. i used a 1 1/2 hp with step 3 pully system and http://www.beaumontmetalworks.com is were i got my contact wheels and other stuff this is for a KGM clone belt grinder and the plans are great good luck

[Pairomedicsfish]

That was easy....thanks!

[AUBE]

I looked into trying it myself and decided it just didn't look worth it. I think the types of electric controllers they use are the same ones you can pick up new on Ebay really cheap. You can find higher hp treadmill motors but as Ray said most are small, and you can find pretty good deals on dc motors through surplus centers and Ebay. Its the nice controllers that cost so much in a dc setup....and the treadmills don't have them.

[Pairomedicsfish]

Great intel....skycraft surplus, about a mile from me has plenty of motors....whar h/p. Wattage or whatever should I look for?

[AUBE]

I'm only using ac so I'm not a good one to suggest dc motors, but I like my 2x72 grinders to be between 1.5 and 2hp.

If the motors are listed by wattage use a watt to hp calculator(just Google "watt to horsepower") to figure out what they equal in hp.

[Ray Rogers]

1.5 to 2 hp is great. Look for that in an A/C motor that runs at 1750 rpm (my preference) if you like a slower belt (and that really isn't all that slow or 3450 rpms if you like a blazing fast belt or if you plan to use pulleys that can reduce the speed and increase torque. Get the motor in 220V A/C if you have the power available or 120V if that's all you have. All of that is for one speed motors, speed control provided by pulleys if at all. This can be had at a very reasonable price and is more than adequate for most people.

For electronically variable speed (as opposed to pulleys) you have a choice (sort of). A real DC motor and controller like the Leeson which will cost in the $700 range new. The downside with DC motors ids that torque drops off quickly as speed is reduced and they never seem to have as much power as they are rated for. I have that set up on my main grinder, a Leeson rated for 1 hp and it is far, far weaker than my 1 hp Grizzly single speed grinder.

The other option is a VFD controller for a 3 phase motor. This is the bee's knees of grinder power plants. Again though, you're looking at $700 or more for a new one. You can do it yourself from eBay parts but the configuring of the controller is not trivial so you need to know what you are doing or have access to someone who does.....