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How To: Washers, Lock Washer, SAE Washer, Fender Washers

How To: Washers, Lock Washer, SAE Washer, Fender Washers

December 15 2015


The main purpose of a flat washer is simple; to keep the nut or the bolt head from driving into the material that you're using. There are a couple of different types of flat washers. You’ve got a USS and your SAE with the same size hole, but the USS has a bigger diameter. The reason is why they use that is because it applies the pressure to a wider surface. You find these typically in just general household applications and they work great. You find SAE washers on a lot of automotive applications where you’ve got a 90 degree angle and you have to get a bolt washer in there, so space is limited. You also have fender washers. Fender washers have the same diameter hole as a regular washer, but you get larger outside diameters. The reason why the call them fender washers is simple. The automotive world uses them on fenders that have sheet metal where you have adjustment and there is a big slot and you got to cover that area so you put a fender washer over it so it bites material. Then there is a split lock washer. You can tell by the split and it's not perfectly straight. The reason why they do that is the same as other lock washers. When you tighten the nut this collapses down and it applies pressure on the nut to keep it from backing off, holding it in place so it does not come loose.

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