Tormach T/C Tapping head... defect?

[apeman88]

I purchased a Tormach T/C Tapping head a few weeks ago to tap a bunch of 6-32 holes but I'm breaking taps every 10th hole or so. I tried Sowa spiral point and spiral flute and both are breaking on me.

I noticed my T/C tapping head is smooth on the downward float compression but binds 1/3 way up on the upward float compression. I'm wondering if this is normal.

Can someone with a T/C tapping head check theirs to see if theirs work the same way?

I've already got a email to Tormach but I think I won't get a reply until Monday being Thanksgiving.

Also... how tight should the clutch be set? I noticed on the downward tap... it goes down smooth but on the upward, the float is working more and my tap seems to be breaking at about 1/3 way up on the float (where the bind is).

See video for more details.


Thanks!

Ken

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[twocik]

I hear a little bit of a kink in the spring pulling outward, but I don't think this should have any effect as long as your code is correct.

I have the same tc head and have never had any problems like that. A little video or pictures helps solve the problem faster. What was your dwell time ? What type of material are you tapping ? Coolant on, oil, etc. ?

Lets see your gcode...

[apeman88]

The kink is what I'm suspecting is the problem. It taps down fine but every 10 or so taps, when the tap is spinning out is when I'm snapping taps. The TC head will also sometimes get stuck on where it kinks making the Z lower by about 1/4" on the next hole. If I tap the TC head with a pencil, it'll snap back up to where it should be.

I'm tapping 6061 Alu but going 1/2" deep. Tried with coolant, tapping oil and WD40... tapping fluid works with best. Below is my code... hope you can shine some light on my problem.

G80
G91 (G28 Z0)
G90
M01
N2 M6 T30
G90 G00 G40 G54
G43 H30 D60 G0 X1.649 Y1.293 Z2. S300 M3
M8
(--------------------------)
(T30 6-32 TAP HOLES - DRILL)
(--------------------------)
X1.649 Y1.293 Z0.4
M29 S300
G98 G84 Z-0.65 R0.4 P0 F9.375
X2.169
X2.689
X3.209
X3.729
X4.249
X4.769
X5.289
X5.809
X6.329
X6.849
X7.369
X7.889
X8.409
X8.929
X9.449
X9.969
X10.489
X10.413 Y0.187

[cgroves]

Hello Ken,

I had a similar problem with my TC head that I posted on previously:
http://www.cnczone.com/forums/830725-post48.html

A circlip in the spring mechanism is the most likely issue.

If you are game to disassemble you'll problem get to the stage where you taken off the ball cage and can't figure hot to get it apart further. There's a small hole through the centre long axis. At the end of the hole is a small slotted head machine screw that keeps the T/C assembly together. It took a while to get a small slotted head screw driver that was small enough to fit but was strong enough to do the job. The machine screw is set with a lot of torque so its hard to get a purchase with the small screw driver. I found the best way was to hold the screw driver in a vice and turn the T/C assembly itself.

When you do get it apart you'll come across the two spring t/c mechanism. Careful when undoing the circlip here as soon as it loosens you have a spring, washer and circlip shooting across your workshop.

Regards, Christian

[apeman88]

Thanks Christian, I'll have to look into that after thanksgiving. Was wondering if I should take it apart since the upward stroke did not feel smooth at all and had some binding. Good to know I'm not the only one with the problem.

Ken

[Scott_M]

Hi Ken
Have you written a custom macro for G84 ?
Tormach does not support G84. On my machine the G84 call exhibits some really strange behavior. Like long pauses in all the wrong places. With no pause when the spindle reverses. My guess is your feed direction changes much faster then your spindle does and you are getting to the limits of the T/C.
Unfortunetly there is no canned cycle for the T/C head. The most efficent way to do it would be to write your tapping in/pause/out code in a subroutine and call it at each hole location.

Scott

[apeman88]

Scott, No... I have not hand coded G84 before... actually... this is the first time I'm machine tapping. Before this, I hand tapped all my holes but this job requires hundreds of taps so I decided to try the TC Head.

I'm relying on SolidCAM's G Code. And after your comment, it does seem dwelling is at the wrong places. As of now, the Z will spin to 300rpm... wait 3 seconds and go down... and as soon as it reaches Z-0.5 (bottom), spindle reverses right away with Z going up at the same time. Once it reaches Z0.4, it stops for 3 seconds before moving X,Y to the next hole and immediately Z moves down and the cycle continues.

Ken

[twocik]

Once I get back home I'll post the code that works for me, maybe it will help. I'm thinking it could be a dwell time issue only because I barely pull the shaft out of my TC head coming up. let me double check my notes...

[Scott_M]

it does seem dwelling is at the wrong places. As of now, the Z will spin to 300rpm... wait 3 seconds and go down... and as soon as it reaches Z-0.5 (bottom), spindle reverses right away with Z going up at the same time. Once it reaches Z0.4, it stops for 3 seconds before moving X,Y to the next hole and immediately Z moves down and the cycle continues.

Ken

That is exactly what I am talking about. The G84 cycle is for rigid tapping. The Tormach does not support it. The T/C head needs about a 1/2 second dwell at the bottom before it feeds out to give the spindle time to get up to speed.

I believe you are getting to the limit of the T/C heads "float" this is why you are breaking taps.

If I knew how to write a Macro I would make one for a Canned cycle for the T/C tapping head it really needs one.

Just a thought...I wonder if you intentionally gave it the wrong feed rate so it would "load up" the head to prepare it for the lack of dwell at the bottom, it may make up for the missing travel.

Scott

[twocik]

This is for a 8-32 through hole and sure with the right clearance you could pull a blind hole off. I'd say .3" clearance would be min for a cutting bottom tap, form bottom tap you could get away with .2 maybe less. Hope this help, good luck with it. Post your parts final results !


( 8-32 tap )
( T18 : 0.164 )
M09
M998
T18 G43 H18 M6
M3 S500
M08
G0 Z0.05
G0 X-2.1584 Y0.0
G0 Z0
M3 S500
G4 P4
G1 Z-0.62 F15.625
M4 S500
G4 P0.5
G1 Z0.1

[apeman88]

No... I'm positive I'm not reaching the limits of the floats. When it starts the reverse, the spindle does catch up fairly quickly... but once every 5th hole or so... the clutch on the TC head slips and I'll reach about 1/3 of the float where the kink is and half the time, It'll snap the tap.

I will reprogram mt code for 1/2 second dwell at bottom of the tap and see if it helps.

SolidCAM self calculated a feed of 9.375 when I put in 300RPM for the spindle. I did double check this number and it is accurate... right?

Ken

[apeman88]

Thanks Twocik... looks like I have to mod my codes and get it a try again.

Ken

[twocik]

I think Tormach told me to use at least 400rpm with this style head, but can't remember why. I'd also check your holes to make sure everything is lining up. Check your drill points to make sure they match your tap points. Next check backlash, runout, head screws, gibs and see if you can prove the tool to be at fault first. Sometimes things can slip by the maker but one thing I've learned is 80% of the time the op is at fault.

[rwskinner]

Mine does the same exact thing, doesn't seem right. Tormach said it was normal when I called but I'm not buying that.

Okay, sorry, I did not realize this thread was so old....

[lens42]

My TC head was very rough sliding. I took it apart (the hidden screw mentioned by another replier is key) and hit all the sliding surfaces with emory cloth (can’t remember the grit). One part that seemed to be catching was the screw itself. It has circular machined lines on the unthreaded shank that is supposed to slide through the spring during T and C. Those lines seem to snag on the spring coils. I took those down to smooth with emory cloth as well. After that the parts slid much better.


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[Steve Seebold]

I use the Tormach ER 16 TTS T/C tapping head. I have developed a process for tapping aluminum and I have tapped holes as small as 2-56 and I haven’t broken a tap yet.

If you’re interested in what I do, shoot me a PM or give me a call at 714-420- 2453 and I’ll be happy to tell you how I do it.

Shoot me a text to let me know when you call because I get so many robocalls if I don’t recognize a number, I won’t answer it.

[jwatte]

If you posted a description here, or perhaps a link to a YouTube video, then your name would become more known and you'd have to take fewer calls.
Hint, hint :-)

[rwskinner]

I finally took mine apart. First, the center screw was really loose. I don't think it would have stayed in there much longer. Also, the guts were full of cosmoline instead of lubricant. I cleaned it all up and found the same issues where the inner spring hangs up on the snap ring. A smaller diameter spring is really needed. I deburred the spacer and ground the ears off the snap ring then reassembled. Its fairly smooth now.

I honestly think if they put a slightly smaller diameter inner spring in there it would solve most of the issues.

My TC head was very rough sliding. I took it apart (the hidden screw mentioned by another replier is key) and hit all the sliding surfaces with emory cloth (can’t remember the grit). One part that seemed to be catching was the screw itself. It has circular machined lines on the unthreaded shank that is supposed to slide through the spring during T and C. Those lines seem to snag on the spring coils. I took those down to smooth with emory cloth as well. After that the parts slid much better.


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[ripperj]

FYI the ER-20 tts tapping head( no clutch) is nice and smooth and works well


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[lens42]

FYI the ER-20 tts tapping head( no clutch) is nice and smooth and works well


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It’s definitely different construction from the one that takes quick-change collets. When I emailed Tormach to ask how to take mine apart, they didn’t even know how. They only knew how to disassemble the ER one.


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