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.

How are screw sizes named?

Thread sizes are given in nominal sizes, not in the actual measurement. The exact measurement is slightly below the named or nominal size. For example, a 6mm bolt may measure 5.8mm or 5.9mm, but it is called 6mm bolt. It is also common to use “M” before the bolt size, such as M6 for a 6mm bolt.

What do screw numbers mean?

The higher the number, the finer the threads, which are best used in metal applications. The fewer the threads per inch, the coarser the threads, the faster the screw will drive and are the preferred threading for wood applications or wood studs.

How big is a #10 screw?

1. The number “10” is used as a size designator and has no numerical meaning. “32” refers to the 32-thread pitch in threads per inch. You can identify a 10-32 screw by measuring the diameter with a ruler at exactly 3/16 inches ().

What does M6 screw mean?

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 0.1 mm. The number 0.1 mm refers to 0.1 threads per millimeter. You can identify an M6 screw by measuring the diameter at slightly more than 7/32″ (0.228″).

How big is a #4 screw?

#4 Designed for small crafts, jewelry boxes, attaching hinges, etc. Very lightduty. Available in 3/8 in. to 3/4 in. lengths.

How do you read screw numbers?

In the Unified Thread Standard (UTS) system, manufacturers list the diameter size as a number between 0 and 10, with 0 being the smallest and 10 being the largest. Screws larger than a #10 have a diameter listed directly in inches. For example, on a #4-40 UNC-3A x . 5 screw, #4 represents the diameter.

What does screw size M4 mean?

The M4 machine screw has a thread diameter of 4 millimetres, in simple terms the M stands for millimetres followed by the size – in this case 4 mm.

What does a #6 screw mean?

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. The smaller the gage number the smaller the screw diameter (opposite of nails and wire diameter).

What size is #12 screw?

The diameters listed in the chart below are in fractions of an inch, so the #12 is just shy of 1/4 inch. A more detailed table with thread count can be found below, along with tap drill sizes. Detailed screw sizes charts.