Having a problem using rigid tapping on my SL10..

[locash]

Preface: Machine is a 2008 Haas SL10

Ok, I'm having a bit of a problem using a regular hand tap in an ER32 collet in my SL10.. The material is 6061-T6 Aluminum, tapping a 10mm x 1.5 thread just over an inch deep into a blind hole.. The threads look beat up in the beginning, but seem to get better deeper into the hole.. I've tried spind speeds from 50 rpm to 350 rpm, and it doesnt seem to matter too much.. Here is my code:

(M10 X 1.5 BOTTOMING TAP)
M09
G28
T707
G97 S200
G00 Z1. M08
G00 X0 Z0.1
G84 Z-1.1 R0.1 F0.0591
G80
G00 Z0.1
Z1.
X2.
G28

Is it the fact that I am using a traditional tap (even though it's new)? Is there a way to do a repeat rigid tap on the lathe, like there is on the mill? Maybe clearing the chips would fix things?

Thanks for any assistance, this thing is driving me nuts, and I'm new to using a lathe, haha..

[Mike Stevenson]

You can "Peck" tap by adding a "Q" value I believe to the G84 line.

[dcoupar]

Have you tried a spiral fluted tap? How about forming rather than cutting?

[locash]

Thanks for the suggestions, guys!

I have not tried a spiral fluted tap, I guess that is next on the list after I try adding that Q value (I just looked in the manual, and it does not list the Q value as an available option for G84, will it work?).. I have never tried forming ID threads before, probably because I don't have the tool to do it..

[Geof]

Use a spiral fluted tap with plenty of coolant, I normally use a richer coolant mix than most manufacturers suggest.

Take your speed up to 1000rpm, I find Haas machines seem to have difficulty holding synchronization when running slow.

If you have the Rigid Tapping option turned on in both the Parameters and Settings then you can peck tap. Just copy the G84 line a few times and put the different Z depths in.

[PBMW]

I'm thinking it's not your machine but your setup.
I'd check to MAKE SURE your tool is:
A.) At X0.0
B.) In the collet true to the Z axis.

Using a bottom tap to drive in an inch is not a great idea. A "Hand tap" is also not a great idea. Use either a spirol fluted tap, not a spirol tiped one...or a form tap.
I'm going to place money on either A or B though.

[Mr.Xtreme]

Hi,

I believe it is also your setup as mentioned.
There are a couple things for you to look at though. 1st thing I can tell you right out the gate is if you are running a full synthetic as we are it is not really suited for alum tapping, mill, lathe, don't matter. You will have gauling problems, but cut some harder material and all is good. You mentioned bottom tap, I hope that is not the case. you really need to use a Gun tap, or a Modified bottom tap from say OSG, but traditonal tap as you said should do ok. Your holder can be off centerline wit the axis. Take out the tooling and put indicator in the spindle, and tram the holder and see how it is centerline. If good, proceed to put in a good sleeve and a straight pc of rod, preferably carbide drill blank or something., tighten slightly to hold straight, Then put indicator on the tailstk rail an sweep the high point accros x axis on the front, note the reading, then move the z axis to do the same sweep at the back of the tool holder. It should be .001 or less. If not then you need to remove, clean, find the cause. Then and only then can your tool track correctly, parrallel to the diameter. Also the holder might be lined up ok both checks I had mentioned here but the x zero centerline might be off center and need to be adjusted, especially if you use a probe. There is a preset value entered using F2 which might not be good any longer and needs to be calibrated back to centerline. Yes you can repeat the tapping cycle going deeper each time as long as part doesn't slip or is removed and you have rigid tapping, it will pick up just like single point threading and not cross thread. My feelings are you are going to find your holder(s) are off center. Good Luck to you.

Paul

[locash]

Thanks for all the advice, it turned out that one of the holders was not perfectly straight as stated.. I am still using the regular bottoming tap and it has worked perfectly for the 60 parts I ran today..

[Mr.Xtreme]

Glad you were able to find the cause and correction.
It is truely nice when things work as intended.

[PBMW]

Yup...an SL10 round tool holder is a trick to get on there straight. You need to make sure it is indexed against the front lip. If not...it is not on correct.