Tightening grinder’s belt using engine weight instead of a spring force

S

Steinmann

Joined
Jan 12, 2010
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The engine will be mounted on a base with a hinge and its weight only will tighten the belt. That is an old method, but my engine weights about 33 lbs – isn’t this too much? I’m afraid that with this weight the belt won’t last for long – am I right or wrong here?
Also – I will be glad to see your grinders that use this method.
Thank you – Michael.
 
I would worry about the motor bouncing and loosing belt friction. I don't think it would work very well, but I've never built a grinder.
 
many folks to it that way , it will work fine . That is how 1 of my machines is done .
 
I've got a grinder that my father made in the 60's set up exactly that way. He was an auto mechanic his entire life, so this thing got a TON of use, everyday for years...still does. Never once has it slipped, and it doesn't wear out belts any faster than my other two which are spring retention
 
MY grinder is built with an under count type mount. Here is a photo from the side of the cart I have my machine mounted on.

Grindercart003.jpg


If you look carefully in this pic you can see the setup I have. The weight of the motor bascially holds the tension on the belt.
Grindercart008.jpg


The motor is on a free pivoting bracket, where the weight of the motor does all of the tensioning of the belt. Like you said the weight of the motor is heavy. However with the 220V motor when the starting capacitor kicks in, it kicks with such force I added a spring to keep it from kicking enough to detract the belt. I was shocked when I first fired it up and saw how much the motor juumped upon starting! :eek:
I am not sure the spring was needed but it limits the amount of upward travel that happens when the starting capacitor kicks in. My fear was that the upward travel would detrack the belt and when the weight of the motor fell back on it, the pulley would damage the belt.
The shear weight of the motor is why there is a handle that sticks out on mine to counterbalance the weight when I have to lift the weight of the motor to change the belt on the 3 step pullies and the gold looking chain is there so that if the weight does get away that I won't bash the motor into the frame below, the chain limits the motor from downfall! This system works well.
 
Thanks a lot for the replies guys, but I mean an abrasive belt, and not a drive belt. In my imagination I'm thinking of planning/building the engine in such a way that the motor drives directly a pulley and it will be hanging on a plate with a hinge. This will keep the abrasive belt in stress (those 33 lbs...) and there will be no need for a drive belt or a spring. Pulling the engine up will allow to change belts. What do you think? Any pictures of such a setup? And will the abrasive belt hang on?
 
I think there will be many issues with that type of arrangement. I've seen it attempted in the past, and there are tracking issues, vibration issues, along with a number of other things that would take very long winded explanations.

If it's something you just want to do, to see if you can, that's up to you, but chances are very good that you'll put all the work and effort into it, only to find that you'll need to go another direction.
 
Ok, to clear things up, I think the drive belt will work fine by motor tension, but the abrasive belt will not.
 
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