G84 1/8 npt thread issues.

[sandrewb]

Im having an issue getting the G84 cycle to work with a 1/8 npt tap. The threads are getting chewed up. At the moment using S225 and F.940 going 10mm deep. Any help would be super. Have kinda read that maybe pecking the tap might work best. Haven't tried that yet.

[epmtool]

What material?

I would recommend threadmilling as you get a perfect thread everytime in all materials. If this is not an option you could try an interupted thread tap.

Here's some good info- Pipe Tapping

I get my npt threadmills from harvery tool and they work great.

[sandrewb]

1117 material

[Delw]

try peck tapping makes a huge difference

[Geof]

Am I confused or do you have the wrong feed?

You have: ....At the moment using S225 and F.940....

1/8 npt is 27tpi so the lead is 1/27=0.0370

At 225rpm this is 8.333ipm

[sandrewb]

Am I confused or do you have the wrong feed?

You have: ....At the moment using S225 and F.940....

1/8 npt is 27tpi so the lead is 1/27=0.0370

At 225rpm this is 8.333ipm

Using metric feeds.

[djr76]

Am I confused or do you have the wrong feed?

You have: ....At the moment using S225 and F.940....

1/8 npt is 27tpi so the lead is 1/27=0.0370

At 225rpm this is 8.333ipm

I was thinking the same thing

Using metric feeds.

8.3333*25.4 = 211.6666 feed in mm

are we missing something here?

[spidrman]

1/8 npt 27tpi the lead is 1/27=0.0370(threads per inch)

At 225rpm this is 8.333ipm(inches per minute)

base on one full revolution

variable depth will not affect the threading cycle

as you can tap 1/4 or 3/8 deep till proper depth

is acquire to Gauge hole been threaded

[RalphWilson]

Im having an issue getting the G84 cycle to work with a 1/8 npt tap. The threads are getting chewed up. At the moment using S225 and F.940 going 10mm deep. Any help would be super. Have kinda read that maybe pecking the tap might work best. Haven't tried that yet.

Ok ridged tapping.
G84 and G84.1
I don't have the ability to use ether one on my machine , because the controller or the machine does not have the ability to do them.

I have come up with a fix to ridged tap using just a liner move at a rpm and feed .
Stop and reverse at a different rate for incinerated speed.
so assuming the metric and imperial units are not getting confused.
I will strictly use English.

G20
M6 T1
G0 G90 H1 Z0
M19
G01 G90 S225 M3  Z-.3937 F8.333 G4 P100
G01 G90 S225 M4 G1 Z0 F8.333 G4 P100
G0 G90 H0 Z0
M30

Notice: I am using G4 as a pause , you could use G9 for a position check.
I suggest using a floating; "Z floating", tool holder for the tap.

[sandrewb]

Whole program is in G99 so would the F value not be..

1/27=.037037
.037*25.4=.940

Other programs in shop running a M14x1.5 taps and F value of 1.5

Could be brain farting here.. let me know

[RalphWilson]

Whole program is in G99 so would the F value not be..

1/27=.037037
.037*25.4=.940

Other programs in shop running a M14x1.5 taps and F value of 1.5

Could be brain farting here.. let me know

the 1/27 is in English or Imperial of .037037 inch per revolution.
you are working in metric.
so of course the 1.5mm is going to be 1.5 mm for a M14 tap.
or .059 inches per revolution for a 1.5MM pitch.
So yes the .94074 MM for F would be correct.
also on another note.
G98 is initial plane return and G99 is referance plane return.
did you mean your using a G99 referance plane return or
Did you mean M99 .... to loop in a program or skip lines of code?
Or M99 sub program return?