Hello Forum,

I am looking for constructive help on threading 1/4x20 holes in .50" 1144 steel, using my PCNC 1100, Fusion 360 and a Tormach tension/compression tapping head.
I tried doing this today and had some trouble. I spotted the hole, drilled it with .201 drill all the way through + .070", then tried to run the tap cycle. The first
hole the tension/compression holder seemed to work fine, no issues but when I tried a 1/4x20 bolt, it would not thread all the way down, through the
material. I looked at my Fusion 360 setup for this op and realized I needed the tapered tap to go more than the +.070" to get beyond the tapered part
of the thread tap.

So on my second test, I set the below hole height to .50" after measuring the tap. This time the tension/compression holder seemed to bottomed out and caused the Z axis to move off its normal top of travel stop position at the end of the tap cycle. I got a yellow flag notice. I then had to reset the X,Y, Z axis stops. So I decided to stop while I was ahead... and seek some help. I am attaching the code for the tap cycle to this post. If anyone has some advice, I would appreciate it. Thanks. Cismontguy

%
(1001)
(Machine)
( vendor Tormach)
( model Tormach PCNC 1100 Series 3)
( description Tormach PCNC 1100 Series 3)
(T79 D=0.25 CR=0. - ZMIN=-1. - right hand tap)
G90 G54 G64 G50 G17 G40 G80 G94 G91.1 G49
G20 (Inch)
G30

N10(Drill2 2)
T79 G43 H79 M6
S458 M3 M8
G54
G0 X0.75 Y2.25
G0 Z0.6
G0 Z0.2
G98 G84 X0.75 Y2.25 Z-1. R0.2 F22.9
Y0.75
G80
G0 Z0.6
M5 M9

G30
M30
%