Grinder motor setup question

[Chiro75]

It seems like with a step pulley setup you should have a way to slack the drive belt to change speeds. Most of the setups I've seen have utilized a wood board the motor is screwed into and a hinge to allow you to bring the motor closer to the drive wheel on the grinder and slack the belt to change it. My question is should this be set up to allow the weight of the motor to tension the belt, or is that too much tension and should the weight of the motor be supported by the tabletop it's all screwed into?

Related question: I assume in setting up the motor that the pulleys should line up on the grinder and motor, right? I am using step pulleys on both, so they should be in line so the belt isn't worn on the side, correct?

 

[razorhunter]

Yes, your belt should line up. No reason to not line it up. Just check out any belt drive grinder pics. You'll see them lining up as usual. If it's a little off, it's not going to hurt anything. Just look at all the HF bandsaws. I've never seen a belt line up perfectly on one of those.. Close, but not perfect.
Some guys also use a spring tension system, just like on an idler pulley, but for the motor...

 

[Ed Caffrey]

I have my grinder motor mounted with a hinge plate. I mounted mine under the bench with a slot through the bench for the belt. (much the same as a table saw motor is mounted.) I did have to use a turnbuckle and a large spring to carry some of the weight, but my motor weighs in at 130lbs. (3hp 190VDC variable)

The pulleys should line up, with the largest front pulley matched up to the smallest rear pulley (or vise versa)

If your using a 1 or 1 1/2hp motor, you shouldn't have any problems with letting the weight of the motor providing belt tension. If the motor are too heavy and you allow the whole weight to ride on the belt, it can quickly wreck the motor shaft bearings, or the drive wheel bearings on your grinder.

 

[razorhunter]

Oooh,
SWEET Ed! 3HP ???? That's NICE...

 

[Ed Caffrey]

I got lucky....purchased the motor off ebay for $200. It came out of the Coors brewery in Colorado. The power will spoil a guy real quickly. I can make the "V" belt slip, but I sure can't slow down the motor! After grinding on it, 1 and 1 1/2hp variables seem wimpy.