Help with screw size?

Looks like your looking at two different screw sizes here. The first number is the diameter. # 10-32 means it is a diameter 10 that has 32 threads per inch. If it said 10-24 then it would have been 24 threads per inch. (per inch of length) The next , 8 x3 is telling me it is a diameter 8 and is three inches long. Number 10 and number 8 are two different diameters and there is no number 3 thread size. Screw diameters are, 14, 12, 10, 8, 6, 4, and 2. Above 14 (which is 1/4) starts going into bolt sizes which are 1/4, 5/16/, 3/8, 1/2, 3/4, 1 inch. Those are standard sizes in U.S. stores and are machine threaded. Wood screws, Sheet metal screws would have the same diameter number but would only go by diameter then length. They don't have a thread number.

You might find out about theses things by going to Hellman.com or to V.S.I.Hardware.com Both supplied nuts and bolts to our hardware store. and supply most all hardware stores still

That is a standard US machine screw thread. 10 is the screw diameter and it is 32 threads per inch. An inch is still an imperial measurement. The 10 refers to 10/ 64 of an inch for the diameter. Readily found in most hardware stores in North America. A 4mm is a little larger and I am not familiar with metric standards. Hope this helps, those screws come in round head, flat head and semi oval head types. All just to confuse the issue.

hard task. seek on search engines like google. that might help!

DON'T KNOW WHERE YOU'RE LOCATED . BRING A SAMPLE TO A HARDWARE STORE

sheet metal?