#6-32 UNC screw The #6-32 UNC is a UTS screw specifying a major thread diameter of #6 which is defined as 0.1380 inches (3.51 mm); and 32 tpi (threads per inch) which equates to a thread pitch of 0.031250 inches (0.7938 mm).
A gage number like "6" is the diameter and the length is the length of the screw that goes into the wood not inclusive of the head unless it's a flat head.
0.156'' Diameter, 0.3750'' Length, 6-32 Thread, Stainless Steel Bright.
ISO metric range. 6-32 means size number 6 and 32 threads per inch. This fastener can also be specified as #6 UNC.
#6-32 UNC screw
The #6-32 UNC is a UTS screw specifying a major thread diameter of #6 which is defined as 0.1380 inches (3.51 mm); and 32 tpi (threads per inch) which equates to a thread pitch of 0.031250 inches (0.7938 mm).
The correct drill bit size for a 6-32 tap is No. 36, with a decimal equivalent of 0.1065.
M6 refers to a metric 6 mm screw. The outside diameter of the threads is 6 mm. The standard metric rack screw is actually an M6 x 1 mm. The number 1 mm refers to 1 threads per millimeter. You can identify an M6 screw by measuring the diameter at slightly more than 7/32″ (0.2362″).
The first number is the diameter. The bigger the number the bigger the screw. The second number is the number of threads per inch.
Metric threads are used outside of the USA, and commonly in products by HP and other global entities. You can identify an M6 screw by measuring the diameter with a ruler. It'll be 6 mm, or slightly more than 7/32 inches (0.228″).
Machine screws are often found in sizes of: 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14—the larger the number, the larger the screw. Machine screws, but especially caps screws and bolts, can range from 1/4 inch up to 3 inches or more.
6mm = almost 1/4 inch. 7mm = almost 9/32 inch (= a bit over 1/4 inch) 8mm = 5/16 inch. 9mm = almost 3/8 inch.
A mil is a measurement that equals one-thousandth of an inch, or 0.001 inch. One mil also equals 0.0254 mm (millimeter). Thus a mil is not the same thickness as a millimeter. The term "mil" is not an abbreviation but a unit of measure.
Q:What size Hex Wrench fits this? A: Everbilt #6-32 x 3/16 in. Stainless-Steel Socket Set Screws (2-Piece) will work with 1/16" hex wrench size.
What it indicates however it that the number following it is the diameter of the screw (or bolt) in millimetres. In the examples shown above of coach screws available in our store, the M6 is a 6mm wide screw (at the threaded part, not the head) and the M8 is 8mm wide.
It is by coincidence that the gauge is approximately the size of the screw head in millimeters. A 6 gauge screw will have a head almost equal to 6 mm wide.