US Fasteners, 1-1/2", Zinc plated steel, 20, External hex

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  Sheet metal screws

  Screws with large threads for use in sheet metal sometimes also used in plastic, fiberglass or wood.

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  Hex bolts

  Bolts with hexagonal heads and machine threads for use with a nut or in a tapped hole. Also known as hex cap screws or machine bolts.

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  Flange bolts

  Flange bolts have a flange on the bottom of the head that distributes the load like a washer.

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  Machine screws

  Screws with machine threads for use with a nut or in a tapped hole.