Hex machine bolts are large gauge, strong bolts with hex heads. They do not have a washer face under the head like hex cap screws. These are heavy duty bolts for heavy duty projects. All of the hex machine bolts Fastener Express carries are galvanized for protection, which makes them an excellent fit for outdoor projects. With fasteners like these, there's no need to worry about a little nature. We also carry an assortment of square machine bolts. If you have any questions or comments, please use the "Contact Us" link at the top of the page.