12 threads per inch. right handed
We use a die of the proper size to cut threads on steel pipe. This pipe die can be turned by hand, or by machine. There are examples of this process in any good hardware or large home improvement store. They have pipe threaders on the premises, and they can thread most common pipe stock.
12r + 4 = 112, 12r = 108, r = 9
12r - 20
A pipe threader is used to thread the inside of pipes with accessories such as a die head, either manually or with a machine. Die heads are usually used with lathes,turret lathes, CNC lathes, or screw machines.
20
It is 12r - 20 or 4*(3r - 5)
The expression is: 12r-20 when simplified
-6r-5 = 7-12r 12r-6r = 7+5 6r = 12 r = 2
12r - 15s - r + 3s = 11r -12s
-1
12r
-1r