The abbreviation UNC stands for "Unified National Coarse", this is thread with a coarse pitch. The tool for UNC is labeled AF. The abbreviation AF means Across Flat (American), this roughly means "measured across" the wrenches fit UNF and UNC threads. If the caliper indicates 9/16 "(14.2mm) when measuring the head, you should use a 9/16" wrench. So the size of the head is decisive.
We sell the fastening materials in assorted bags in the most common sizes 1/4 ", 5/16" and 3/8 ". You can also contact us for individual items, send an email to firstname.lastname@example.org for a quotation.
UNC thread table: Bolt length table:
|Size (inch)||Size (mm)||TPI||Length (inch)||Length (mm)|