So that's why the bushing is eccentric !!

fredsheldon · Post by **fredsheldon** » Thu Jun 21, 2012 2:14 pm

As I was taking my headstock apart in preparation for the arrival of my new PowerPro I wondered why the heck the bushing on the idler shaft was not round. After sanding and turning three pens last night my upper belt started slipping when I attached my band saw to cut more wood blocks. It was time to hit this site looking for possible causes when I discovered that you can adjust the tension of the belt by turning the eccentric bushing. I guess I need to watch all the sawdust sessions before I discover any new tibits of information the hard way, after something breaks. I did notice that the upper belt deflected at least an inch or more before I quit for the night and figured that it might be the problem. I hope that is all it is. I will find out tonight. I love this forum

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dusty · Post by **dusty** » Thu Jun 21, 2012 2:32 pm

fredsheldon wrote:As I was taking my headstock apart in preparation for the arrival of my new PowerPro I wondered why the heck the bushing on the idler shaft was not round. After sanding and turning three pens last night my upper belt started slipping when I attached my band saw to cut more wood blocks. It was time to hit this site looking for possible causes when I discovered that you can adjust the tension of the belt by turning the eccentric bushing. I guess I need to watch all the sawdust sessions before I discover any new tibits of information the hard way, after something breaks. I did notice that the upper belt deflected at least an inch or more before I quit for the night and figured that it might be the problem. I hope that is all it is. I will find out tonight. This forum great.

After loosening the bolt that releases the eccentric, adjust the eccentric for the correct belt tension and then tighten the bolt that secures but BE CAREFUL. You can break that ear that the bolt goes through if you over tighten.

Notice that when you adjusted the eccentric to increase belt tension that it did not need to be held to maintain belt tension. Similarly, it does not take a great deal of pressure to hold the eccentric.

JPG · Post by **JPG** » Thu Jun 21, 2012 3:33 pm

Be aware that the older version has a set screw that secures the bushing as well as the 'ears'.

fredsheldon · Post by **fredsheldon** » Thu Jun 21, 2012 11:15 pm

Ok, I'm back in business. I rotated the eccentric bushing from the 6:00 position clockwise to about the 10:00 position and the belt is not slipping anymore. Or was it from 10:00 to 6:00. Now I'm not sure which way I went

Thanks for the suggestions about not tighting the bolt to much. In fact it was already loose. Could this have caused the bushing to rotate and loosen the belt tension? Or did the belt just stretch through normal use? How often does the belt have to be adjusted under normal use.

JPG · Post by **JPG** » Fri Jun 22, 2012 11:35 am

fredsheldon wrote:Ok, I'm back in business. I rotated the eccentric bushing from the 6:00 position clockwise to about the 10:00 position and the belt is not slipping anymore. Or was it from 10:00 to 6:00. Now I'm not sure which way I went Thanks for the suggestions about not tighting the bolt to much. In fact it was already loose. Could this have caused the bushing to rotate and loosen the belt tension? Or did the belt just stretch through normal use? How often does the belt have to be adjusted under normal use.

The amount of slack you mentioned above is quite extreme to have occurred 'suddenly'.

Methinks the looseness caused it to gradually rotate(towards 6:00) and the resulting looseness was not evident until a greater load was applied.

10:00 indicates the belt has stretched, but still has a lot of useful life left.

Prudence suggests getting one before it fails. Store it with the poly-v/gilmer surface 'out'.

mikelst · Post by **mikelst** » Fri Jun 22, 2012 1:59 pm

JPG40504 wrote: Store it with the poly-v/gilmer surface 'out'.

I don't understand why this would be the preferred storage method.

I have mine in the bag it shipped in and it is not like that. Should I open the bag and turn the belt inside out?

JPG · Post by **JPG** » Fri Jun 22, 2012 2:06 pm

mikelst wrote:I don't understand why this would be the preferred storage method. I have mine in the bag it shipped in and it is not like that. Should I open the bag and turn the belt inside out?

The belts tend to take a set when stored for a long period. Inverting them seems to help prevent that. Also it causes them to acquire a more round shape. The bag is good if it does not cause an elongated shape.

Bill Mayo likes to also apply belt dressing to help keep them pliable.

I tend to pay attention when he 'speaks'!