14 rows Your shopping cart is empty. Subtotal: $0.00 Quick Add Cart / Checkout: Quick Add 23 rows Machine Screw Size Chart and Conversion Tables A #8 screw size is .164 fraction of an … A number 4 size screw comes from the fact that it is the fourth ina series of screw sizes. The screw sizes start at number 0 with adiameter of 0.060 and increase by 0.013 for each size larger.

A number 4 size screw comes from the fact that it is the fourth ina series of screw sizes. The screw sizes start at number 0 with adiameter of 0.060 and increase by 0.013 for each size larger. The diameter refers to the major diameter , or outside edge, of the threads. If the screw size includes a dash with a number following it, that is the number of threads per inch (tpi). Usually tpi is only shown with machine screws or other fasteners with machine screw threads. So, a 1/ 4-20 screw has a 1/ 4 diameter (.250) with 20 threads per inch. 20 rows * Major thread diameter is measured on the outside of the threads. For more information …

7 Answers. 6 is a # 6-size screw . Screw gauges are a measure of the head size and shaft size, and are roughly linear but not quite a 1:1 relationship (a #8 screw is a little less than twice the diameter of a #4 screw ). There isn't a good system for converting gauge to a calibrated measurement , so you're best off consulting a table like this:. SCREW SIZING. The 8 refers to the size ( diameter ) of the screw, and the 32 means it has 32 threads to the inch. The diameter is measured at the shank of the screw. Screws are sized by gauge number and length. For example, an 8 gauge screw with 32 threads per inch and 1 in length would be written as: 8 …