Fastener Express has a huge variety of hex cap screws and slotted flat cap screws in both SAE and Metric measurements. Cap screws are great for bringing strength and reliability to projects. They are fitted for pre-threaded holes and usually do not need to be used with a nut. Because of a widened diameter near the cap, they are excellent for establishing a tight, lasting point of connection. These screws are available in alloy steel, zinc, stainless steel, silicone, and cadmium.