The abbreviation UNF stands for "Unified National Fine", this is thread with a fine pitch. The tool for UNF 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. The length measure is measured from under the hex head to the end of the bolt. The bolts are available in two different versions, tap bolt (full thread) and shoulder bolt (half thread). The thread and length are indicated in INCH (25,4 mm).
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 email@example.com for a quotation.
UNF thread table: Bolt length table:
|Size (inch)||Size (mm)||TPI||Length (inch)||Length (mm)|