Author Topic: Drive belt tension (Read 2285 times)

Grower · « **on:** July 12, 2008, 02:39:24 AM »

Hello, is it necessary to have the drive belts from the engine to the drive pullies tensioned using spring pressure? Or could they just be tensioned up till tight enough.

Bibbyman · « **Reply #1 on:** July 12, 2008, 04:23:17 AM »

I hear that over tighten a belt and you could risk burning out the bearing on the engine or motor and or the drive wheel bearing. Under tighten a drive belt and it’s likely to slip.

Experience goes a long way – kind of like grilling steaks – takes some feel to know when they’re right. I have a belt gage I use to measure the deflection at so many pounds of force.

The main drive belt on a mill with an electric motor have to be just right or else they burn real bad and life is short. So we have to watch and deal with the main drive belt more often than if we had a mill with an engine. The reason being, the electric motor does not idle like and engine but always running at say 3,200 RPMs.

D Martin · « **Reply #2 on:** July 12, 2008, 08:53:10 AM »

I once had a belt tensioned too tight and my clutch broke at where the pully is pressed on the clutch housing . If my belt is too tight the band will not stop at idle. It cost me 135.$ to figure out that belts can be a little loose and be ok. Mine actually looks like it flops around a bit at full throtle, tensioned propperly. A small engine rental repair guy who I bought the clutch from told me to press with one finger on the v belt and it should deflect about an inch.

Bibbyman · « **Reply #3 on:** July 12, 2008, 11:19:22 AM »

I’m pretty sure pounds of force and deflection depends on application, belt design, number of belts, and distance between pulleys. Our LT40HDE25 has a single three V belt. Wood-Mizer specs 7/16” deflection at 18 pounds for our mill.

I was instructed by a Wood-Mizer guy on how to calibrate a belt’s tension. He poked his finger into my shoulder and said he used about this much force. He really didn’t explain how much deflection he was looking for.

Grower · « **Reply #4 on:** July 12, 2008, 06:32:37 PM »

Are any of these belts spring loaded via the tensioning system? One can imagine they would have to be to compensate for flying debris etc coming between the belts and the pullies. We intend spring loading the one I am building.

Tom · « **Reply #5 on:** July 12, 2008, 06:43:07 PM »

The drive belts on my 3638 baker are spring loaded. They are tensioned via a spring loaded idler that remains tensioned all of the time. The saw depends on a centrifugal clutch to separate the power from the wheels.

Grower · « **Reply #6 on:** July 12, 2008, 09:16:42 PM »

Yea, we have two grain augurs here one is a 40 footer and and has a Wisconsin motor on it, the other is PTO driven, both use 3 V belts and neither system has spring loaded belts. The engine driven one just has a 4 foot lever on it to manually tighten and loosen the belts, they never smoke as all the augur does when it gets over loaded is stall the engine, I reckon I can away without the spring system and just direct drive, however it could be changed later if necessary. Thats the thing about being your own engineer, make it how you like it, if it doesn't work it can be changed at a later date. :-)

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