hese fasteners are very similar to hex bolts. They differ mostly in that they are manufactured to tighter tolerances than the corresponding bolts. Machinery's Handbook refers parenthetically to these fasteners as "Finished Hex Bolts".Reasonably, these fasteners might be referred to as bolts, but based on the US government document Distinguishing Bolts from Screws, the US government might classify them as screws because of the tighter tolerance.Our company is specialized in making fasteners, we can provide a variety of bolt,nut,anchor.like:hex bolt,hex nut ,wire rope.We have our own warehouse, standing stock, we can open molds to make products through the drawings provided by customers.we provide the best service.