Re: Do it yerself DIY Belt Wrap Kit for less than $25
Originally Posted by tighed1
There's been some interest in my DIY Belt Wrap kit so here goes.
PARTS LIST
1 - Idler Pulley, NP 1202000470 (same as supercharger idler pulley)- $10.30 at Rock auto.com LINK shipping is about $10 also????
1 - M8-1.25 bolt, 75MM long1 - M8-1.25 nylon locking nut1 - Spare washer laying around the garage
A word of caution.
Not all bolts are created equal, some bolts are made from any old piece of metal that can be purchased cheaply and some bolts are made from high tensile steel. The quality bolts are from well known manufacturers like Allen and and Unbrako, these are made from HT steel with a tensile strength of 190,000 PSI minimum. These bolts are made to high standards with forged heads, rolled threads and fillets, bolts that are found at Home Depot etc are just bolts and are inferior, the cheaper ones have cut threads and fillets, this makes them weak, the steel these are made from has a tensile strength of 40,000 to 100,000 PSI.
In this application with an unsupported load on the bolt even the best bolt will fail from fatigue at some point. Bolts are strongest taking tensile loads not unsupported side loads.
The initial load bends the bolt and the belt will flex the bolt all the time when running, this is not good and will cause the bolt to break suddenly. I am not saying it might break, I am saying it will break.
If this bolt breaks what will the damage be? I think that it will probably exceed the $175 saved.
This pulley should be supported on the end and a quality bolt used. Even the cheap bolts will last if the bolt and pulley are supported.
Last edited by onehundred80; May 16, 2009 at 02:00 PM.