Gerry, I'm running Tormachs latest, PCNC1100M3-IIRell3.12b, the licence info shows R3.042.029 as the Mach version.
I was running a pretty simple program. Just a .75" linear feed in, CCW .25" arc in, a CW 360 degree 2.75" circle, & a CCW .25" arc out.

Here is the code:
%
N100 O0000 (CUTTER COMP TEST 2)
(MASTERCAM - X3)
(PROGRAM   - CUTTER COMP TEST 2.NC)
(DATE      - NOV-27-2010)
(TIME      - 10:39 AM)
(T23  - EM, 1/2, 4 OAL, 3F, FN, PM - H23  - D23  - D0.5000")
N102 G00 G17 G20 G40 G80 G90
N104 M998 ( TOOLCHANGE )
N106 T23 M06 (EM, 1/2, 4 OAL, 3F, FN, PM)
(MAX - Z1.)
(MIN - Z-.5)
N108 G00 G90 G54 X1.8934 Y.4419 S3000 M03
N110 G43 H23 Z1.
N112 G00 G90 Z.1
N114 G94 G01 Z-.5 F64.
N116 G41 D23
N118 X1.6282 Y.1768 F15.
N120 G03 X1.555 Y0. R.25
N122 G02 X-1.555 R1.555
N124 X1.555 R1.555
N126 G01 Y-.01
N128 G03 X1.6271 Y-.1872 R.25
N130 G40
N132 G01 X1.8905 Y-.4541
N134 G00 G90 Z-.4
N136 G00 G90 Z.1
N138 G00 G90 X1.8884 Y.4419
N140 G01 Z-.5 F64.
N142 G41 D23
N144 X1.6232 Y.1768 F15.
N146 G03 X1.55 Y0. R.25
N148 G02 X-1.55 R1.55
N150 X1.55 R1.55
N152 G01 Y-.01
N154 G03 X1.622 Y-.1872 R.25
N156 G40
N158 G01 X1.8855 Y-.4541
N160 G00 G90 Z1.
N162 M09
N164 M05
N166 M998 ( TOOLCHANGE )
N168 G28 Y0.
N170 G90
N172 M30

It looks to me to be correct...?

Barry

It's a bad idea to do 1/4" arcs with a 1/2" tool. It throws an error for me there. Try making them .26". Any inside radius should always be larger than the tools radius.

OK, I'll try that tomorrow...thanks.

Barry

That did the trick, I've had the mill running with different diameter offset for the last 12 hours and all is great.

Thanks again Gerry for the help!!!

LOL, I sympathize with Brian (and Art before him).  Cutter comp is HARD!

I'm in the middle of implementing it for the G-Wizard G-Code Editor.  The doc from my Fanuc manual is 40 pages long.  It's filled with probably 20 or 30 geometry diagrams that show what Fanuc Type "C" comp is supposed to do in various cases. 

Much easier to write software that doesn't do cutter comp.  OTOH, much easier for people to deal with g-code with the help of cutter comp.

Cheers,

BW
www.cnccookbook.com

cutter comp for mach 3 works good. I discovered a minute ago that my earlier posted code was fine except it lacked one move per cut;

-
*G0-X.5 Y.5
G1 Z-.03125 F15.
*G41 X0. Y0.
X16.25 Y0.
-

G41 is not modal n must be put in with a small move to fixture offset position (cut start point) per cut.

Perry A.

cutter comp for mach 3 works good.

It does a lot of the time, but not always.