Looking for a program to do a 3/4"-14 npt exterior thread on a lathe. I cannot figure out from the machinery's handbook how to figure out the "x" number in the 2nd G76 line......
Would someone explain how to come up the the "x" in the G76 cycle for both inside and outside threads. I can figure out the tapers to rough turn or bore the stock to. I can also figure out the "r" value in the G76 line, but not the x......
Here is a blurb on G76 threading. If you are doing an NPT thread you will have to use the R(i) value to taper the thread. The value is an interger number with 1 being equal to .0001" and is the difference in radius from Z start to Z finish. Hope this helps you out.
WHERE
m = SPRING CUTS (01)
r = CHAMFER AMOUNT(00)
a = TOOL ANGLE (80 60 55 30 29 0)
min = MINIMUM DEPTH OF CUT
fin = FINISHING ALLOWANCE
Øfin = ROOT DIAMETER
len = LENGTH OF THREAD
i = THREAD RADIUS DIFFERENCE
k = THREAD HEIGHT (RADIUS)
1st = 1ST CUT DEPTH
L = THREAD LEAD