Screws
 

Forgive my incompetence, but could someone please explain the screw measurements on my B4?

I've got the manual so I know which sizes I need, but what do they mean? What is "4-40 x 3/8"?

I need to get hold of some 2-56 x 5/16 (holds the front bulkhead brace on) but I can't find any, anyone got any ideas?

Click here for an explanation.

The 4 is a number that refers to the major diameter (#4 = 0.1120 in);
The 40 is the number of threads per inch (UNC is typically used).

The remaining fraction (5/16" in your case) is a reference to the length of screw. Note that for cap and button heads this dimension does not include the head, but will for those that have a countersink.

Hope that helps :)

Ah, it makes sense now. Thanks for that!

I've ordered a Nor-tech screw set so that should do me hopefully...