On 2015-04-15, Gunner Asch wrote:
On Wed, 15 Apr 2015 09:26:22 -0400, Joe Gwinn
wrote:

In article ,
Ignoramus18077 wrote:

On 2015-04-13, Don Foreman wrote:
On Sun, 05 Apr 2015 07:47:14 -0500, Ignoramus10114
wrote:

I have an aluminum heatsink that I need to tap , I wanted to know if I
should use 6-32 or some less coarse thread like 8-32 would be better?

6-32 is an abomination. If you are ever going to break a tap, it'll
probably be a 6-32. The 32-pitch thread is too coarse for the skinny
diameter. The standard should have been 6-40.

If you insist on tapping aluminum, use plenty of lube. A lube that
works really well in aluminum is ... Goo Gone! Orange Goop works
quite well also. Both have high content of d-limonene. Use HSS taps
rather than the sharper and cheaper but much more brittle carbon
steel taps found at hardware stores.

I agree -- and I am very happy to see you Don!

I go the other way with aluminum -- I use forming taps, not cutting
taps, and lubricate with soft wax made for the purpose. One drills the
hole somewhat larger than for cutting taps. Forming taps have more
meat in them, so are harder to break. Works very well.

Joe Gwinn

I do much the same.


I ended up doing the same with screws -- drilled a 1/8" hole and
threaded the screws right in. Worked like a charm.

i