[RussMachine]

DAMMIT !!!
I was tapping 4 holes, (1/4-20) through 1/2" steel plate, and I forgot to do an M4 reverse on the last hole.
OOPS!!!
The head retracted (or TRIED to retract) back up in Z, as I frantically hit the Feedhold, reset, E-stop all at once when I saw my tap holder streeeeetttchhhinng........
I think the motor overload actually stopped the motion.
CRAP!
So I loosened the drawbar, retracted Z, and manually unscrewed my tap.
Now the spring inside my T/C Holder seems a bit loose.
Me thinks I stretched it a bit.
I re-ran the holder to check it out, and it seemed fine. It tapped the holes Ok after the stretch.
Lesson learned: DOUBLE CHECK TAPPING PROGRAM.
Time for a stiff drink.

[mountaindew]

Looking to add one to my crib. Learning tapping cycles and including them in overall part code is next in my education plan.
Are you using a canned cycle, sprut or your own code?
md

[Hirudin]

I haven't done a lot of tapping, but when I do I write out a subroutine so there isn't any chance of making a mistake like that. Below is my subroutine template file that I use to tap M3 holes.

If you use this template the first thing you'll want to do is change the rotational speed. I tap at 550 RPM*.

You'll note the four lines that look like this: "(/////////////////////)". Between the first two there needs to be a list of all the coordinates for all the holes you need to tap. Each coordinate needs to be followed by "M98 P1000". Between the third and fourth markers needs to be your tapping code. Basically your "tapping code" will probably involve...
1. rapiding down to a minimum clearance level
2. feeding down to your desired tap depth
3. stopping and reversing the spindle
4. feeding back up to the minimum clearance level
5. rapiding up to a safe traverse level
6. stopping and reversing the spindle again
After the fourth marker you'll notice the "M99" command. That tells the machine to resume the original code.

This section of code, the subroutine, will be run each time the "M98 P1000" command is executed. Since this command has been entered after each set of coordinates the machine will execute your tapping subroutine at each hole location.

If you have multiple hole depths you can create multiple subroutines. In my example the subroutine is called "O1000", if you need another just call it "O1001" or something like that. I'm not sure if there are any restrictions on the number of subroutines you may have or what they may be called. I doubt it, but to be safe I've just been conforming to the "O100_" convention and it's worked fine. Obviously, you need to add "M98 P1001" at every location that you want to run the "O1001" subroutine.

I hope this helps!

%
G90 G17 G40 G80 G00 G50 G94 G64 G21


G0 M06 T00 (M3x0.5 Procunier)G43 H00
S600 M03

G00 Z10
(/////////////////////)
X133. 
M98 P1000
(/////////////////////)
G00 Z10.
M05 
M30
%

(f / p = s)
(f = s * p)
O1000
(/////////////////////)
G00 Z2
G1 Z-8.5 F275
G1 Z2 F550
G00 Z10
(/////////////////////)
M99

%

In case it's not clear, if you wanted to tap three holes at (X, Y) "10, 25"; "10, 50"; "30, 50"; and "40, 80" you'd need the section of code between the first two markers to look something like this...

(/////////////////////)
X10 Y25
M98 P1000

Y50
M98 P1000

X30
M98 P1000

X40 Y80
M98 P1000
(/////////////////////)

* (550 *actual* revolutions per minute are achieved when I tell my machine to run at 600 RPM).

Some additional info is in the description of this video...
https://www.youtube.com/watch?v=VGhm96ntPAY

[RussMachine]

MOUNTAINDEW, I make my own code for tapping. Tormach suggests using long-hand code instead of G84, because the Tormachs don't have TRUE rigid tapping.
It's not hard to do, just M3 (forward), then feed down, Pause, M4 (reverse) feed up.
I just had a Brain-Fart and forgot to reverse the spindle, and I was in a hurry, AND I didn't check the program. Stupid me.
I like HIRUDIN's idea of the Sub-Program. One idiot-proofed program repeated at all of your hole locations.

[mountaindew]

Thanks for examples Hirudin! and tips, Russ
This should not take long to get hang of. I do see a tachometer for calibrating rpm speed would be handy.

Thanks again for great answers .
md

[Fastest1]

Impressive display of tapping. Beats the Makita hand drill with a clutch, thats for sure.

Is it just me or is there an optical illusion occurring in this video? I swear on occasion it appears to peck once and then smoothly feed in. On the others it just feeds in smoothly from the beginning. I watched it more than once to verify I was losing my mind. Is this really happening and if so, why? The holes appear to be the same in regards to diameter and chamfer.

[sansbury]

I also use a subroutine, so no chance for this particular failure mode. I still haven't found a way to deal with the FRO, SRO, or belt settings to interfere, but so far the TC head has soaked up those errors without complaint.

In general, I try very hard these days to avoid hand coding. It has its uses but most of the time it's just an opportunity to screw something up. And as you learn your CAM application, it will become faster almost all the time.

[mountaindew]

I also use a subroutine, so no chance for this particular failure mode. I still haven't found a way to deal with the FRO, SRO, or belt settings to interfere, but so far the TC head has soaked up those errors without complaint.

In general, I try very hard these days to avoid hand coding. It has its uses but most of the time it's just an opportunity to screw something up. And as you learn your CAM application, it will become faster almost all the time.

I agree,
Sprut has spoiled me. First couple hours were tough to get going and understand what its doing and now it is down right fun and powerful.
I was thinking it exports a list of hole positions. I could set up subroutine and positions as noted above using spruts list. I tend to do all drill operations first and could include tap code here.
Then load another file to complete that side of part or set of operations .
Is this one of your strategies?

Other ideas or hints?

[sansbury]

Is there a way you can get Sprutcam to post your subroutine for tapping operations? To be honest I'm still working on that part, though I can't give you specific guidance as I run BobCAD and LinuxCNC, and haven't bothered since I don't do a lot of tapped holes. Well, I didn't until I made a fixture this weekend with 60 10-32 holes, which made me think it's time to figure out how to get Bob to post my subroutine instead of rigid tapping G-codes. As it is, I do it kind of like you say--let the CAM drill everything and then do a second program (or edit the CAM-generated program) to include tapping subroutines.

[CadRhino]

Thanks for posting your mistake. It helps others like me to learn. I haven't used my T/C head yet but have a better feel for what can happen.
Best,
Nathan

[mountaindew]

I will do more research . I know there is a way to include your own code or operation in any part of the code generated by sprut and have it included in post.
How to do this I have no idea yet. Was wanting to learn a few way to do this. turbostep and a few around here i bet know a dozen ways to do this
I see these types of mill operations will be required a lot in my ideas and its also the one of the most labor intense things I do in my shop.
So easy to misalign .... then your finished parts don't fit without bind....
And yes my dewalt tap machine is what I been using for years cordless screw gun... perfect control for taping soft stuff anyway.. hard as hell even with guides to align the way I need much of the time tho.

Thanks for input!

[tbaker2500]

Impressive display of tapping. Beats the Makita hand drill with a clutch, thats for sure.

Is it just me or is there an optical illusion occurring in this video? I swear on occasion it appears to peck once and then smoothly feed in. On the others it just feeds in smoothly from the beginning. I watched it more than once to verify I was losing my mind. Is this really happening and if so, why? The holes appear to be the same in regards to diameter and chamfer.

I've never used a T/C head. But my first guess is the tap hanging up on entry to the hole until the compression is taken up?

[Hirudin]

Impressive display of tapping. Beats the Makita hand drill with a clutch, thats for sure.

Is it just me or is there an optical illusion occurring in this video? I swear on occasion it appears to peck once and then smoothly feed in. On the others it just feeds in smoothly from the beginning. I watched it more than once to verify I was losing my mind. Is this really happening and if so, why? The holes appear to be the same in regards to diameter and chamfer.

Thanks!

I think tbaker2500 pretty-much has it. The Procunier doesn't have much compression per say, but inside the head there are two clutches - one on the top and one on the bottom. There is a small gap between the clutches. When the tap is being driven into the hole the top clutch is engaged (this links the tap rotation with the spindle rotation) and when it's being pulled out the bottom clutch engages (which reverses the tap rotation). I'm guessing that when the tap leaves the hole the spindle of the Procunier maintains contact with the bottom clutch and since there's no resistance on the tap it stops spinning counterclockwise and spins along with the mill's spindle. It's not until it hits the next hole that it gets pushed away from the bottom clutch.

[SCzEngrgGroup]

The Procunier may be different (though I very much doubt it), but all the tapping heads I've looked at are spring-loaded so they always return the the forward-driving, 1X-speed direction. Getting stuck in the other position would make a mess if the tap engaged the work.

Regards,
Ray L.

[TurboStep]

While I have nothing against writing G-Code I don't like to mix CAM and hand coding in one project - just a personal preference.
If you're using Sprut you may like to check out this method suggested by Tormach:
Tension/Compression Tapping and SprutCAM « Milling Around
I only use thread milling so I haven't used this method yet. I will be using my T/C head sometime in the future and this is the approach I'll be trying first.
Step

[mountaindew]

While I have nothing against writing G-Code I don't like to mix CAM and hand coding in one project - just a personal preference.
If you're using Sprut you may like to check out this method suggested by Tormach:
Tension/Compression Tapping and SprutCAM « Milling Around
I only use thread milling so I haven't used this method yet. I will be using my T/C head sometime in the future and this is the approach I'll be trying first.
Step

That will do it!
Figured there was a way. I looked at this in sprut but did not know how to set it up or what it worked with.
I watched video before, but did not go or see a link to page showing the settings on milling around.
Need to get a tc unit and a on the way now.
Thanks for all the help Everyone, this is making my education fun!
md

[Hirudin]

The Procunier may be different (though I very much doubt it), but all the tapping heads I've looked at are spring-loaded so they always return the the forward-driving, 1X-speed direction. Getting stuck in the other position would make a mess if the tap engaged the work.

Regards,
Ray L.

Oh yup, it does have a spring. Maybe it's not strong enough or something. It looks quite a bit like the tap is stuck down and gets pushed back into the neutral position when it touches the material.

[SCzEngrgGroup]

Oh yup, it does have a spring. Maybe it's not strong enough or something. It looks quite a bit like the tap is stuck down and gets pushed back into the neutral position when it touches the material.

I'm assuming the Procunier has basically a dog-clutch, like the Chines tapping head I had? If so, I would guess the dogs are worn, and binding. Might be a good idea to open it up and file the dogs to it doesn't do that. Might just need a cleaning and a little lubrication. I assume you bought it used?

Regards,
Ray L.

[Hirudin]

It was actually brand new. I had done this job once before (this video was of my second run). I was actually thinking the sticking might be from being new.

Perhaps when I swapped the collet spindle for the quick change spindle I forgot to put the spring back in or something. I did the swap when it was completely new and I did note there was grease of some kind in there. Maybe it stays sticky for a while. :/

I just watched the video again. Sometimes the tap collet stays visible at the top of the screen and sometimes it doesn't. So the amount it retracts is definitely inconsistent, one way or another.

There's a diagram of the innards in the manual (PDF): http://www.rockford-ettco.com/Downlo...5000-16000.pdf

P.S.
I just reread my speculation in my post above; although it might look like I was saying that it is *suppose to* act that way I was actually only trying to explain what I thought appeared to be happening. I'm sure returning to the neutral position after every hole is the way the tapping head is suppose to work.

[Superman]

Tormach suggests using long-hand code instead of G84, because the Tormachs don't have TRUE rigid tapping..

You are not doing rigid tapping ( unless the tap is held in a collet chuck, side lock holder or similar solid holder )

.... You have a Tension/Compression holder for allowing the tap to "end float" as the spindle stops & reverses ( feed reversing is more instantaneous )

You can use the G84 canned cycle. Feed should be 95-100% of the lead, so that the holder slightly extends as it is going down ( the holders tend to have more tension movement than compression )
- do try to use the cycle, as it will eliminate errors in long hand programming ( like what happened )

Note
program tapping in feed per rev...then the feedrate starts at being the thread pitch, and you can alter the programmed spindle RPM without having to adjust the feedrate
---- always set back to feed per minute at the end of tool use, or you will be spotting holes at ( what seems to be ) rapid