[rrossey]

I am doing rigid tapping for the first time on Haas Mini Mill
Material: Aluminum 6061-T6
Tap size: #10-32
Tap: HSS Spiral Flute Tap (Greenfield)
Full thread depth required: 0.5”
It is a blind hole drilled to 1.2” depth

I tried with 500 rpm (Too low I presume). The chips get entangled in the tap and are not thrown away by the coolant. I tried going 0.25” full thread depth only.

What is the recommended rpm for this tap size?
By using higher rpm and increasing the R plane value from .1 to .4 will help?
Can I go the depth of 0.75” in one shot? (this will give the full thread depth of 0.5”)
Thanks,
R. Rossey

[PBMW]

A couple of questions first.
Blind holes like a spirol flute tap becaue the chips come out the top. Thru holes like a spirol tip tap because it pushed the chip out the bottom
I like form taps because there are no chips and you can go faster. Of course the drill size is not the same...
That said, I tap at about 1500rpm on my mini. Everything from 000/120 to 3/8-16
I usually leave about .05 at the bottom of the hole on a form tap for clearance

[rrossey]

Thanks for the suggestion.
With a form tap, can I go the full depth in one shot?

[PBMW]

I do all the time.
I have a part that I do on my lathe that has a 5/16-18 thd. 1.25 deep. I form tap it at 2000 rpm. I do these on my SL10 Haas with no issues
Just be sure to look in the machinerys handbook for the correct tap drill. It is NOT the same as a regular cut tap. It is a significantly larger drill. Use th ewrong drill and you'll break taps

[fuzzyracing1967]

I have several parts that we tap 10-32 holes that deep and a little deeper.The one thing I would do is up the rpm to 1500.As for it being a blind hole you have plenty of extra depth,so no problem there,same goes for the spiral taps.Your r value dosn't efect anything as far as the tapping,that's just a start point. The one thing we do that may efect it, would be that we modified the flexable coolant line so that it sprays a very small tight steam of coolant staight into the hole as it's tapping,this may help with chips.
Hope this helps

[bishb25]

Form tapping works very well in aluminum. If the coolant proves inadequate we will turn off the coolant and brush some "PRO-TAP" on the tap. You can even put the PRO-TAP in a hand pump oil can and squirt it directly into the hole.
P.S. Remember you can only rigid tap up to 2000 rpm on most HAAS mills.
Also, check setting #130 "tap retract speed" I like to set this to "1" when tapping shallow holes at high RPM. Based on discussions I've had with HAAS techs I believe this reduces possible synchronization error (not 100% sure if that's true, but just a quark I have).

[PBMW]

I HATE that 2k rpm limit.....

[fuzzyracing1967]

(I HATE that 2k rpm limit.....)
I agree,it would be so much fun to tap at say 8000rpm's

[Geof]

(I HATE that 2k rpm limit.....)
I agree,it would be so much fun to tap at say 8000rpm's

Have you watched how fast the spindle gets to when tapping. I set the speed at 1000 rpm and rarely does it reach that before it stops and backs out. Setting a higher speed would be no faster.

[PBMW]

Yea, I know that too Geof. I was watchin a pallet changer Robodrill the other day in a friends shop. 24K spindle, Just BLAZING fast. Not that much more money....

[Geof]

I guess the Robodrill has a small spindle; less rotating mass so it can accelerate faster. There is quite a difference between tapping cycle times on our Super Minimills versus a VF2 with the same program.

[slatern44]

What's the max tapping RPM's on the VF-2?

[bishb25]

Like I said 2000 RPM.

I'm not 100% sure on this, but I think you can tap at higher RPM if you turn rigid tapping off and use a floating tap holder. The RPM limit is for synchronization reasons, however, a floating tap holder will offer some forgiveness.

[rrossey]

How important is the quality of cutting fluid/coolant?

I tried the #10-32 form tap by drilling with #16 drill. Five holes were tapped to the full depth very well but on the 6th hole tap broke.
The coolant is due for change, so can the coolant be the culprit?

[bishb25]

Cutting fluid is extremely important.

Do you have good coverage with the coolant? High volume, lots of pressure? The MINI-MILL comes with a pretty weak coolant system if you ask me. I put a wye on my nozzles and reduced the size of the tips to get better coverage and more pressurized streams of coolant.

Proper lubrication is a major key to good threads. Especially form tapping. As I said in an earlier post; try turning off the coolant and brushing your favorite tapping oil on the tap or squirting it in the hole.
We like "PRO-TAP" from Tap-Magic. It works great on almost all metals, even aluminum.
We also form tap a lot of a copper alloy which is very abrasive to HSS cutting tools so we use chrome plated taps. They last 2 to 3 times longer than most other coatings.

Oh, one more thought just came to me. Form tapping does require more torque, therefore, it puts more stress on the tap, but a 10-32 hole in aluminum shouldn't be this much of a problem.

[slatern44]

Oops, I thought the max was 4000 of the VF line 2000 on the mini's. Guess I didnt read enough. Maybe I have just got lucky on the job that I have been running on my new VF-2 since december. I have tapped 192,000 M2x0.4 holes and only on my second tap and that's because I broke the drill because of a loose part. I'm tapping at 3900RPM's because I thought that max was 4000.

[bishb25]

I'll check my manuals again, but last I heard it was 2000 rpm on all machines. My newest machine is going on 5 yrs old now, maybe HAAS has upgraded since then. Don't know.
The reason your 4000 RPM tapping is successful could be because the spindle rarely reaches max programed RPM during tapping due to the ramping required by the acceleration and deceleration needed to make a smooth in and out tapping motion.
(Does that make sense? I'm pretty tired at the moment)