Tap Selection For 6061 Aluminum

[RJS100]

When I started rigid tapping aluminum, I purchased some YG1 combo taps (bottom and spiral flute). They work ok if I use a tapping with chip breaking cycle. I recently spoke with the technical supervisor at YG1 and explained that the Combo tabs worked ok in aluminum as long as I used chip breaking and that I thought the taps struggled sometime backing out of the hole. He explained that these are their bestselling taps, but they are not designed for aluminum.

He further suggested I use either their ALU taps which are specifically designed for aluminum or I could use their form taps. He favored the form taps and noted that with form taps you don't need both bottoming tap and spiral flute taps, one form tap does both.

I put a bunch of stuff in the cart when he was talking and accidentally ordered a few ALU taps. I tested them tonight with his suggestions:
- tap depth = 2.5 x diameter
- Surface speed = 50 sfm

They worked fairly well, but I still needed to use the chip breaking cycle with a peck depth of 50% of the hole depth. I was disappointed that even with Aluminum specific taps, I still could not get a nice, tapped hole without the pecking cycle.

My question: Is this normal for tapping aluminum? Are these just crappy taps? If I use form taps, can I tap to 2.5 x Diameter without pecking?

Thanks... Richard

[suntravel]

Hi Richard,

I also recommend tap forming, no chips, faster, better threads.

3XD is no problem in one go, I use these for Aluminum:

https://webnavigator.guehring.de/en/too ... earch=true

Both forming and tapping at 90 sfm

Without flood cooling a drop tapping fluid in the holes.

Uwe

[tblough]

"Bottoming and spiral grooves in one step" Always a pleasure training bots.

[RJS100]

Thanks. I will try these taps next time I place an order. The YG1 rep also told me to use the following calculator to select the appropriate drill sizes for tapping. He suggested 65-70% for the thread percentage instead of the 75% that I have been using.

http://theoreticalmachinist.com/

Richard

[suntravel]

You can use the CamCut mobile App.

Drilling too small will cause more problems than drilling a little bit larger.

https://www.camcut.fi/en/support/camcut-mobile-app/

Uwe

[RJS100]

Will do... Thanks