Newbie- NPT threads

[mkimco]

I have a 1996 cincinnati avenger lathe trying to cut 3/4 npt threads. Using the G33 code, machine will not recognize G76, can't figure out what to put in to make it cut tapered. I have no problems with cutting the straight threads. Any help would be appreciated.

Thanks

[Karl_T]

does this help? three different controllers G33

3.1. Mitsubishi G33
Mitsubishi lists G33 for both thread cutting and tapping
G33 Z# Q# E#(F#)
Z is thread length
Q is the shaft angle for the start
E is the thread lead
They select either tpi or lead using a parameter elsewhere.


3.2. SIEMENS 840D, EMCO Variant
EMCO lists G33 for both thread cutting and tapping
G33 X# Z# I/K#
X is end position in X for thread
Z is end position in Z for thread
I/K is thread pitch

3.3. OKUMA OSP 2200 ('80 vintage)
G33 X# Z# I# K# F#
X is start position of thread (depth)
Z is end position of thread
I is amount of taper in radius
K is change in lead per revolution (varible pitch thread)
F is lead
G22/23 turns chamfering on and off
you would set a starting point with a G0 away from thread then G33 would rapid in X to start point, feed to programmed Z point, feed out in X then rapid back to the G0 programmed point

[mkimco]

i will give these a try and get back to you. I don't know if it makes a difference but the controls are acramatic 850sx. Thanks

[mkimco]

None of these worked for me. The format for this controls is very different from what I'm used to. It will read anything in () unless you have (MSG,) at the beginning of the line that you have in (). Here is what I have to do the 3/4 npt but there is no taper in it.

(THD, H0D.01A30X.96768Z.2)
G33Z-.7395K.07143
(ENC)

THD=telling machine to thread
H0/H1=either TPI or vari. lead
D=depth of cut
A=entry angle
X=minor dia.
Z=start Z
I think I'm doing this right, but I am a lathe novice.