need TEFC?

A TEFC would be a definate plus around a grinder, especially if you plan on using it for major metal removal. Keeping all the junk out of windings is always a plus. You can get by with an open frame as long as you provide a suitable shield. Metal grit is fairly heavy, tends to fall out quickly and not float in the air like wood dust. If you make a good shroud, it will keep 90% of the crud off the motor. The shroud should be a least 3 or 4 inches bigger than the motor for good cooling, should cover the motor in the front and sides, can be open on the back and bottom.

If this is for home sh> Hi,

Hi, I might be running it for a couple hours at a time, but with breaks of many hours if not days in between those couple hours. And it won't all be hard load, either; the belt sander is for shaping knives, and while there will be heavy stock removal immediately after annealing, there's also a lot of finesse work to get it to an even shape.

-Bernard

If you want to know what I think, I don't even think TEFC is enough, I'd use a completely sealed motor. Have you ever seen any grinder with an open motor? But if you choice is TEFC or open dripproof I'd for sure go with the TEFC and I'd also use shielding.

GWE

To see grinders with a open motor look here.

Both of the grinders in the background of that pic have open frame motors. Both are much older than I am. A bearing went out on motor of the grinder on the left several years ago while it was still at my former employers. At that time I took the motor apart and cleaned it up. It was nasty to say the least but then what do you expect from 40 years of running. :-)

If the motor's free or dirt cheap, use what you can get. If you have to buy a motor, make sure it's sealed.

Chris