wes
It refers to the diameter of the screw. More precisely, it is a 0.138" diameter screw. You can get it in with various head style and thread pitch.
It means that there is .5mm from a particular spot on one thread to the corresponding spot on the next thread
If you mean 'Screw Thread' I will give examples, but first understand that the word screw is a process. It is something you can do. We often say 'Screw these pieces together'. Now some examples :- Top of a toothpaste tube with a screw on lid. top of a jar of food with a screw on lid . A screw thread inside a water tap handle. Most common of all of course is a wood screw, and a metal thread screw or bolt.. Also the screw thread on the cap of a bottle of soft drink.
the 'thread'.
A thread angle is the angle of the threads relative to the shank which is 60 degrees for unified screws The lead angle is the pitch of the screw divided by the circumference of the shank; it varies but is around 3 degrees
The proper thread notation for a 14mm diameter screw with a 1.5mm pitch and 40mm length would be M14x1.5x40.
when lead of the screw is equal to the pitch it is called single threaded screw
the parts of the screw are thread, pitch, and the last is bolt
The standard size and thread pitch of a camera mount screw is 1/4"-20.
This is a tool that is used to measure the pitch diameter of a screw. This tool looks like a standard micrometer except that the anvils are specially configured to reach into the screw thread groove and touch the pitch diameter of the screw thread. The screw thread micrometer does not measure any other aspect of the screw thread. It does not measure the: pitch; threads-per-inch; major diameter; minor diameter; flank angles; lead; helix angle.
The IMA (ideal mechanical advantage) of a screw is determined by the ratio of the circumference of the screw head to the pitch of the screw thread. The formula for calculating IMA is 2πr/p, where r is the radius of the screw head and p is the pitch of the screw thread.
Screws have three main dimensions: diameter, length, and thread pitch. The diameter is the measurement across the screw shaft, the length is how long the screw is, and the thread pitch is the distance between each thread on the screw. These dimensions determine the size and compatibility of the screw for different applications.
Thread
The standard size of a camera mounting screw is 1/4 inch and the thread pitch is 20 threads per inch.
The dimensions of an M3 screw are 3mm in diameter and the thread pitch is 0.5mm.
The dimensions of an M4 screw are 4mm in diameter and the thread pitch is 0.7mm.
pitch = 1/Threads per Inch So for a 1/2 - 20 thread the pitch is .1