AN3H Bolts -- Drilled Head
AN3H bolts have a 10-32 thread with 0.406 inch thread length. The head of each AN3H bolt is predrilled for safety wire.
A or no A? AN bolts were originally designed to be used with a castle nut and cotter pin, so the base part number indicates a drilled shank. The addition of an "A" at the end (for example, AN3H-13A) indicates a drilled head and an undrilled shank for use with safety wire and a self-locking nut.
AN bolt nomenclature can be confusing. Please take a look at our page on Identifying AN Bolt Sizes.