Threading help

[KTECH]

Ok here is a threading question for you smart guys. I am cutting a pipe thread on a mid 80's super slant with the general numeric controller. Here is the problem. I am cutting 2 threads on this part to begin with. I start by turing a 1.230 lenghth for 7/16 20 threads. I am tryin to do this end first because it has a spec taper on the very end. Between the two threads there is a .100 sholder also. So I am trying to cut the pipe thread in reverse so speak. The program looks like this. G00 z-1.850 x.185; G76 x.200 z-1.550 I K.02963 E .03703 D01196 A30. I am missing the page in the manual that tells me what every thing means. I tried calling tech support a million times and nevr got through. Any help would be great not sure what the I is for.

[Karl_T]

This may not help, but here's my hardinge CHNC instructions with a Fanuc compatible control.


'*******TWO LINE FANUC G76 INSTRUCTIONS*********************

'NOTE: Use G0,G1 to position machine at start of thread(Z) and retract height(X) before G76 lines.
' Important: X position determines ID or OD threads


'EXAMPLE G76 LINE 1 FOR 1/2" ROD 20 TPI
'G76 P011060 Q50 R10
'first two digits after P number of finish cut passes
'second two digits after P number of leads to pull out/10, 10 is 1 lead
'third two digits after P is tool tip angle, tool will infeed at 1/2 this angle
'Q is minimum DOC cut in tenths, example 50= .0050 depth radius
'R is DOC finish passes in tenths
'S is optional spindle speed, spindle must be running with an earlier M3 M4 code

'EXAMPLE G76 line two 1/2" rod 20 TPI .5" long 1 thou taper (Z 0 at start of thread)
'G76 Z-.5 X.4567 P433 Q100 F.05 R.001
'Z is end of thread Z value
'X is final diameter of thread value; minor dia. on O.D., major dia. on I.D. (LH) threads
'P is thread height in tenths, 433 is .0433 high, generally COS(infeed angle)*1/thread pitch
'Q is depth of cut for first cut in tenths
'F is feed per thread, 1/LEAD for US
'R is for tapered threading difference in X from start to finish in Z

[KTECH]

Thanks for the respose so quick. Ok from what you are saying I understand that part. Now in the book it shows A as only two different things. Either 29 or 30. Well I am going to start at playing here this moring again so ill post the results that I get later. I was able to get it feed back wards into my taper yesterday so I was happy to get a taper going any way.