[JohnToner]

Ray,

Monday or Tuesday I'll be tapping 1/4 20 RH in 1/2" 6061 with #7 through holes and a spiral tap Will this code work?

G1 Z0.1000
M3 S400 F20
G1 Z-0600
M4 S800 F40
G1 Z0.1000

Thanks,
John
Or, did I just break a cheap tap inside an expensive part?

[kstrauss]

Consider using a thread forming tap in a T/C tapping head or they should work fine in your Procunier (I don't have one to try...). If you drill the right size holes thread forming taps work wonderfully and there is no swarf to jam things.

[SCzEngrgGroup]

Ray,

Monday or Tuesday I'll be tapping 1/4 20 RH in 1/2" 6061 with #7 through holes and a spiral tap Will this code work?

G1 Z0.1000
M3 S400 F20
G1 Z-0600
M4 S800 F40
G1 Z0.1000

Thanks,
John
Or, did I just break a cheap tap inside an expensive part?

Where are you going to find a 1/4-20 tap 600 inches long? :-)

Actually, you DON'T reverse the spindle and DON'T change the RPM with a taping head, so remove the M4 line entirely. ALL you need to do is retract at 2X the downfeed rate, and the tapping head will reverse the rotation automatically. You should also pull out further, since the tapping head will trail the spindle coming out. You need to retract far enough to make sure the tap has completely disengaged before moving the to next hole.

G0 Z0.1000
M3 S400 F20
G1 Z-0.600
G1 Z0.2500

Regards,
Ray L.

[JohnToner]

Thanks Ray,

I'll retract a bit further and also search for that missing decimal point. It must be around here someplace ;-)

[Hirudin]

Oops, I didn't see the page of replies...

Ray,

Monday or Tuesday I'll be tapping 1/4 20 RH in 1/2" 6061 with #7 through holes and a spiral tap Will this code work?

G1 Z0.1000
M3 S400 F20
G1 Z-0600
M4 S800 F40
G1 Z0.1000

Thanks,
John
Or, did I just break a cheap tap inside an expensive part?

I'm a little rusty, but I see a couple problems...

Line 3: you're missing the decimal point - gotta watch out for those!

Line 4: here you're doubling the speed (S), not the feed (F) - You probably want to change the "F" value to 40 and keep the "S" value at 400. Since you're keeping the speed consistent, you can omit the "S" command entirely.

Also, as SCzEngrgGroup pointed out: don't reverse and retracting higher is a good idea.

Potential issue: in the code shown you do not establish a feedrate for the first G1 move. This being the case, the first move (to Z0.1) will go at whatever feedrate your machine was set to before loading this code.

I'd do it something like this...

M3 S400
G1 Z0.1000 F50
G1 Z-0.600 F20
G1 Z0.2500 F40

The info in the description of my video below might be helpful...

https://www.youtube.com/watch?v=VGhm96ntPAY

[JohnToner]

It tapped 7 holes without a hitch. One thing I did after I discovered that my OSG 1/4 20 spiral tap was made in Mexico, (a country that makes "Made in China" look good), was to add an M1 after each hole was tapped so I could clean the tap an apply tapping oil. Probably unnecessary but no big deal. I copiously flood but since my tap was "Hecho en Mexico", I killed the flooding during tapping and squirted some tapping oil.

M3 S450
G00 Z0.1000
G1 Z-0.600 F20
G1 Z0.300 F40