How to find a Bolt or Screw size.

- All bolts are called out with diameter first, then length, separated by "x". To search for a bolt that is 1/2 inch in diameter and 6 inches long is 1/2 x 6.
- All screws are called out with diameter first, then length separated by "x". To search for a #6 diameter screw that is 1/2 inch long is #6 x 1/2.
- Machine screws are called out by TPI (threads per inch). You can find the common coarse and fine threads here. A 6-32 x 3/8 machine screw is a number 6 screw with 32 TPI that is 3/8 of an inch long.Tapping screws, sheet metal screws, self drill screws, any screw that you cannot put a nut on (i.e., sharp threads), can be called out with or without the TPI. If you are not calling out the TPI, always use the pound sign "#" to indicate a number size screw. Usually self drill, thread forming and thread cutting screws are called out with the TPI, and all others, like Type A and Type A/B, are called out with a "#" To ask for a 6 diameter, 1/2 inch long self drill screw, you would call it out as 6-20 x 1/2. A number 6 diameter, 1/2 inch long type A/B tapping screw would be called out as #6 x 1/2.