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Snapping taps with a Procunier on the Series 3
In 6061, 0.75" blind holes, drilled with a No 21 (0.159) bit, cleared out, full of aluminum specific tapping fluid.
10-32 HSS spiral flute tap bought from McMaster: McMaster-Carr
Program using M871, spindle speed of 1000, tapping head settings to Procunier and TPI of 32 for 871. Tap to 0.6 into the hole.
First try, snap on withdrawal. This also happened the last time I tried to do this in brass. Brass? I've tapped many holes before with no problem.
Am I missing something? I did order some of the taps Tormach sells to try. I'd go manual if these little taps had a dimple for a tap guide.
PS, any tips on removing the @#$%ing tap appreciated. I assume the $60 worth of 1" 6061 plate is headed to the recycle bin.
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Re: Snapping taps with a Procunier on the Series 3
For machine tapping, especially when going that deep, you need to use a lower thread percentage, which means a larger drilled hole. For 10-32, use #18 instead of #21. Or, if you need a 75% thread, only machine tap to 0.5" depth, then do the last 1/4" by hand, or using a drill-driver. Also, PLENTY of oil, or aluminum tapping fluid, not coolant.
If you want to preserve the hole, take the plate to a machine shop with an EDM machine, and have the broken tap removed. You can also drill out using a carbide endmill, though it will trash the endmill. After drilling it out, you can clean up the hole, and turn a plug with a heavy press fit (0.003" or so), then press the plug in, surface it flush, and re-drill and tap the hole.
Regards,
Ray L.
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Re: Snapping taps with a Procunier on the Series 3
Thanks. I think I will try the machine/hand approach. I was thinking about that.
Fussed over my spindle calibration and got it within 1% for the speed used for tapping.
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Re: Snapping taps with a Procunier on the Series 3
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Re: Snapping taps with a Procunier on the Series 3
Seriously, get yourself a set of tap extractors, they work very well and no damage to your part from trying to mill them out or the expense of edm.
Tap Extractors for Machine Screw, Hand, Pipe & STI Taps | Walton
walt
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Re: Snapping taps with a Procunier on the Series 3
Just guessing here but you might also try drilling deeper, tapping more shallow, and dropping the spindle speed to 500 rpm or so. I've been tapping a lot of 8-32 blind holes lately with a spiral point tap and notice the tap might run a couple of threads deeper when the program depth is reached before the spindle fully reverses. Drilling 0.75" deep for a nominal 0.50" deep tapped hole and tapping at 500 rpm has worked flawlessly for me in aluminum.
I've only tried spiral flute taps but have had more trouble with them snapping than with the spiral point taps, maybe because of the depth I was tapping. I've started using form taps and am growing to prefer them, at least for smaller holes.
Mike
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Re: Snapping taps with a Procunier on the Series 3
I drilled a 10 24 out of an aluminum part with a carbide spotting drill. I lined it up in the old Bridgeport, locked the xy down and slowly advanced the spindle, drilled it out and didnt damage the spotting drill either maybe a stroke of luck??
edit: I am relatively new to this machine tapping, but on my 5mm .8 (close to 10 32) holes I use 320 rpm 10 ipm, drill for a 75% thread.5 second delay at the bottom of the hole, seems to work fine.
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
waltpermenter
I have other extractors but had no idea those existed. Seems they may be less effective with spiral flute taps as there is little room for the fingers, but I'll get a set anyway as I do use form taps too.
Thanks for all the suggestions everyone.
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Re: Snapping taps with a Procunier on the Series 3
I noticed that both of these taps snapped at the same spot - just at the top of the spiral flutes. Maybe that's a weak spot on these taps?
What brand taps do you all use and where do you get them? 10-32 most of the time, with the Procunier head.
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
Beezle
I noticed that both of these taps snapped at the same spot - just at the top of the spiral flutes. Maybe that's a weak spot on these taps?
What brand taps do you all use and where do you get them? 10-32 most of the time, with the Procunier head.
Curious..... are you using a rigid tap cycle with a T/C holder ? or a sold collet type holder ?
---- some machines say they have "rigid tapping" ....but .... they don't lock the spindle rotation with the tapping axis.....spindle stopping & reversing when feed dead stopped, is NOT rigid tapping
Suggest using a T/C holder, even if you do have rigid, just to take some of the shock off the tap when reversing the spindle.
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Re: Snapping taps with a Procunier on the Series 3
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
Superman
Curious..... are you using a rigid tap cycle with a T/C holder ? or a sold collet type holder ?.
As the thread titles says, he's using a Procunier tapping head.
Regards,
Ray L.
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Re: Snapping taps with a Procunier on the Series 3
I have a similar setup with a Procunier and a Series 3. I was snapping taps until I got a tachometer and calibrated the spindle speed. That got things pretty close, but I got things even closer by picking a certain speed (lets say 1000 rpm) and then just before tapping that day, recording the actual speed with 1000 rpm selected (lets say 1012 rpm). I then tweak the spindle speed up or down until I get my desired 1000 rpm (or as close as possible). The other thing I did was to set my Z travel to lets say 31.25 inches per minute (1000 rpm divided by 32 threads per inch). I then lifted the head as high as possible and timed it with a stopwatch as it went down for a certain distance. For example G01 Z-15.0 F31.25 I timed the head travel for 10 of those 15 inches (to let the machine accelerate and decelerate to the proper speed). It should take 28.8 seconds to do 10 inches. It doesn't. So I figured out a speed that will give the required rate. I did this for all the regular tap sizes, RPM and speeds and wrote it down. Now I just look it up, and I don't break taps anymore.
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Re: Snapping taps with a Procunier on the Series 3
Spindle speed should not be at all critical, as the distance travelled with the tap engaged in the workpiece is so short. Just for added safety, you should under-feed slightly (5-10% is typical), to ensure you don't push the tap. The tapping head will dis-engage and re-engage automatically if you're going too slow
If your measured travel times are not VERY close to what they should be then something is VERY wrong somewhere. Acceleration time should insignificant unless you have it set ridiculously low.
Regards,
Ray L.
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Re: Snapping taps with a Procunier on the Series 3
Velocity - anyway I can get that info from you - I'm sure it's closer than my setup now - but you did watch my video right?
Ray - Good info on downfeed, I think there is "pull" left in the tap head - but at the same time there is still some slop in push. Not sure if it matters or not with the slow speed of a Tormach
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
BAMCNC.COM
Velocity - anyway I can get that info from you - I'm sure it's closer than my setup now - but you did watch my video right?
Ray - Good info on downfeed, I think there is "pull" left in the tap head - but at the same time there is still some slop in push. Not sure if it matters or not with the slow speed of a Tormach
Tapping heads are different - the cheap Chinese ones are knock-offs of the Tapmatics, while the Procunier is another, far better, animal entirely. The Tapmatic have a pretty wide range of compliance on both directions - you'd have to over or under feed by a considerable margin to have any problems. I've accidentally run up to 30% over-feed with no problems. The Procunier is, I think, not as forgiving about over-feed, as I don't believe they will compress further from the fully engaged position the way the Tapmatics will. So it is wise to under-feed by 5-10%. Both heads, when under-fed, will simply dis-engage and re-engage as needed to stay in an acceptable range of travel. The major advantage of the Procunier is it uses conical friction clutches, rather than dog clutches. This makes the engagement very smooth, where the Tapmatics and Chinese head engage with a Bang!, which is stressful on the tap.
I got a deal on a Procunier head a couple of weeks ago - $100 for a 1E in perfect condition. I haven't tried it yet, as I'm going to convert it to use quick-change tap holders before I start using it.
Regards,
Ray L.
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
BAMCNC.COM
Velocity - anyway I can get that info from you - I'm sure it's closer than my setup now - but you did watch my video right?
Ray - Good info on downfeed, I think there is "pull" left in the tap head - but at the same time there is still some slop in push. Not sure if it matters or not with the slow speed of a Tormach
I watched your video the other day when I was pondering this issue.
I am curious what led you to use a drill cycle vs. plain code or the 87x macros?
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Re: Snapping taps with a Procunier on the Series 3
Ray, I'll slow the down feed by 5% from now on.
Beezle - HSMWorks uses only "cycles" for drilling, so I had no choice but to try it. However with a post edit I can now have it do long hand g-code and it works with the numbers I enter for feeds now. I'll probably never use a cycle again - but it works.
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Re: Snapping taps with a Procunier on the Series 3
I am not making any claims that these numbers are at all appropriate, only that I am using them on my Series 3 with a Procunier with some success in a non-production, limited run, environment.
Aluminum
6-32 S950 (corrects to 1000 rpm) F33.6 (corrects to 31.25 ipm)
8-32 S950 (corrects to 1000 rpm) F33.6 (corrects to 31.25 ipm)
10-32 S488 (corrects to 500 rpm) F16.8 (corrects to 15.625 ipm)
1/4-28 S488 (corrects to 500 rpm) F19.2 (corrects to 17.86 ipm)
Mild steel
6-32 S721 (corrects to 750 rpm) F25.2 (corrects to 23.44 ipm)
8-32 S721 (corrects to 750 rpm) F25.2 (corrects to 23.44 ipm)
10-32 S721 (corrects to 750 rpm) F25.2 (corrects to 23.44 ipm)
1/4-28 S327 (corrects to 333 rpm) F12.78 (corrects to 11.89 ipm)
I use spiral flute bottom taps and leave 0.15" at the bottom of blind holes.
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Re: Snapping taps with a Procunier on the Series 3
Not to derail the thread, but I had a similar issue this weekend - 0.75" through holes in 6061, drilled 0.1590", tapping 10-32 with spiral point tap and Procunier head.
I used the recommended M871 cycles with a P of 1.0 (from a 0.2 clearance height), but broke the tap on the 2nd hole when I was tapping full depth. After that I switched to a manual 'peck cycle', 0.3 at a time, and got good results on the other 150+ holes (making a tooling plate).
Is there a better/faster solution? Does anyone else use peck tapping with the Procunier?
Thanks-
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
BAMCNC.COM
Ray, I'll slow the down feed by 5% from now on.
Beezle - HSMWorks uses only "cycles" for drilling, so I had no choice but to try it. However with a post edit I can now have it do long hand g-code and it works with the numbers I enter for feeds now. I'll probably never use a cycle again - but it works.
Here's the tapping head code I use in HSMXpress:
case "tapping":
if (tool.type === TOOL_TAP_RIGHT_HAND) {
writeln(" (Tap: " + formatComment(tool.description) + ")");
writeBlock(gMotionModal.format(0), zOutput.format(cycle.retract));
writeBlock(gMotionModal.format(1), zOutput.format(z), feedOutput.format(F));
writeBlock(gMotionModal.format(1), zOutput.format(cycle.retract + 0.75), feedOutput.format(cycle.feedrate * 2));
//onDwell(1.0);
writeln("");
}
break;
This goes in the big switch statement in the OnCyclePoint method.
Regards,
Ray L.
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Re: Snapping taps with a Procunier on the Series 3
I have tapped thousands of holes on my PCNC 1100 using a Tapmatic 30X tapping head, and the only time I have broken taps is when I do something really dumb like make an X or Y move before I pull the tap out of the hole.
I don't use the M871 tapping cycle. I will always G code my tapping routines, and since I started using a T/C tapping head, I don't use the Tapmatic head any more.
I have tapped holes as small as 0-80 on my machine with no problems.
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Re: Snapping taps with a Procunier on the Series 3
Will you share your T/C Gcode?
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
kstrauss
Will you share your T/C Gcode?
Sure, here you go.
S500M3
G0G90X(FIRST HOLE) Y(FIRST HOLE) Z.25 G43H(OFFSET NUMBER)M8
I always start .25 above my part
G1Z- (DEPTH) F14.0625 (10% less than calculated feed rate)
M4
G4P.25
G1Z.25F17.1875
M3
G4P.25
Copy above
Move to next hold
Paste
When I get down to 6-32 and smaller holes, I use 5% increase and reduction, and I have tapped holes as small as 0-80 with form taps.
I will never use a cutting tap when a form tap is available. Every tome I use a cutting tap, I always manage to leave some of it in the hole.
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Re: Snapping taps with a Procunier on the Series 3
Awesome Ray!!!!
As for the guy with broken spiral POINT tap - those are to be used with through holes only. Form or Spiral FLUTE taps are for blind holes.
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
Steve Seebold
I have tapped thousands of holes on my PCNC 1100 using a Tapmatic 30X tapping head, and the only time I have broken taps is when I do something really dumb like make an X or Y move before I pull the tap out of the hole.
Quote:
Originally Posted by
Steve Seebold
I will never use a cutting tap when a form tap is available. Every tome I use a cutting tap, I always manage to leave some of it in the hole.
I'm suffering from cognitive dissonance trying to reconcile your two statements.... You never "break" (cutting) taps, you just "always" leave pieces of them in the holes? I daresay most of us would call those "broken".
Regards,
Ray L.
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Re: Snapping taps with a Procunier on the Series 3
lol, I assume he means chips?
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Re: Snapping taps with a Procunier on the Series 3
Seems like it also might be the case that he broke a lot of cutting taps ("I always manage to leave some of it in the hole") then he switched to forming taps and has great success ever since ("I have tapped thousands of holes") aside from a few screw-ups here and there.
OT talk over? Talk about cross-threading.
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
BAMCNC.COM
As for the guy with broken spiral POINT tap - those are to be used with through holes only. Form or Spiral FLUTE taps are for blind holes.
I'd agree that spiral point taps are preferably used on through holes, but they do work just fine on blind holes so long as the hole is drilled a fair amount deeper than the depth you tap. For 8-32 holes, I've been finding that 0.750" deep drilled holes can be reliably tapped to 0.500" deep in 6061 with a decent tap lube and a tension-compression tapping head at 500 rpm.
Mike
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Re: Snapping taps with a Procunier on the Series 3
Even if you grind the point off it's still pushing chips down your hole - why get a dental pick, and pick them out when you don't need to?
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
BAMCNC.COM
Even if you grind the point off it's still pushing chips down your hole - why get a dental pick, and pick them out when you don't need to?
Spiral point taps are stronger than spiral flute taps, so harder to break. They are also often significantly cheaper. It's not always necessary to pick the chips out of the hole. In a blind hole, the chips will often get so tightly packed in, you can just leave them where they are. Rather than keeping a stock of both kinds, I find I can get by with only spiral points.
Regards,
Ray L.
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Re: Snapping taps with a Procunier on the Series 3
I bought a few spiral point (form?) taps to try out for blind holes. Someone told me that form taps are great so why not? The spiral point taps I bought look like form taps to me, so I assume that's what they essentially are?
And on the original break, I am trying the Alum method. So far, so good. About half the tap is dissolved at this point.
http://www.nvxd.com/forum_source_2/XT1F1653-web.jpg
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3 Attachment(s)
Re: Snapping taps with a Procunier on the Series 3
Spiral point, spiral flute, and forming taps are all different kinds.
Spiral flute...
Attachment 255256
Spiral point...
Attachment 255254
Forming...
Attachment 255252
Images from McMaster-Carr...
McMaster-Carr
Note how they added in the chips; coming out the top for spiral flute, coming out the bottom for spiral point, and missing (not being created) from the forming tap.
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Re: Snapping taps with a Procunier on the Series 3
It's very easy to distinguish form taps from cutting taps. Cutting taps have sharp cutting edges, form taps do not - they are generally a more triangular profile, with rounded corners, and no flutes.
From top down: Spiral Flute tap, Spiral Point Tap, Plug Tap, Form Tap
http://www.metalformingmagazine.com/...-Fastening.jpg
Regards,
Ray L.
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
Hirudin
Spiral point, spiral flute, and forming taps are all different kinds.
Spiral flute...
Attachment 255256
Spiral point...
Attachment 255254
Forming...
Attachment 255252
Images from McMaster-Carr...
McMaster-Carr
Note how they added in the chips; coming out the top for spiral flute, coming out the bottom for spiral point, and missing (not being created) from the forming tap.
Ah, thanks. So I am using the correct taps for blind holes.
For now, I will probably stick with a spring loaded tap guide and hand taps. :) Most of the parts I make are one-offs anyway. I don't mind writing a little code for the tapping head, but this has been too much hassle.
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Re: Snapping taps with a Procunier on the Series 3
Yup! Wasting many hours (or days) trying to fix a tap that broke while trying to save 10 minutes can really ruin a day (or week). :p
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
SCzEngrgGroup
It's very easy to distinguish form taps from cutting taps. Cutting taps have sharp cutting edges, form taps do not - they are generally a more triangular profile, with rounded corners, and no flutes.
From top down: Spiral Flute tap, Spiral Point Tap, Plug Tap, Form Tap
http://www.metalformingmagazine.com/...-Fastening.jpg
Regards,
Ray L.
not quite, the 3rd one down is a bottom tap, a plug tap is pointy like 2nd one down. many other taps can be plugs or bottoms too,plugs are pointy.
walt
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
Hirudin
Yup! Wasting many hours (or days) trying to fix a tap that broke while trying to save 10 minutes can really ruin a day (or week). :p
yup, keep a set of tap extractors on hand and you could be back in business in a couple minutes.
walt
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Re: Snapping taps with a Procunier on the Series 3
Quote:
Originally Posted by
waltpermenter
yup, keep a set of tap extractors on hand and you could be back in business in a couple minutes.
walt
I have lots of extractors and they do work for some things, but not this one.
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Re: Snapping taps with a Procunier on the Series 3
Once you learn how to use form taps in aluminum, you'll never go back to cutting taps.
Form taps cost a little more, but you'll soon see, once you get used to using them, you'll quit using cutting taps.
You need to drill your holes to pitch diameter size, and use plenty of coolant, but you'll soon like the idea of NO CHIPS packed into the bottom of the holes.
You can google form tap drill sizes and get all the information you need.