Well it all turned out OK. By drilling for 50% threads, using sharp HSS
taps, and some Tap Magic, it was like cutting aluminum, maybe even
easier since it didn't tend to gum up.
Here's the finished product - a Swaglok plug valve with an AX-12A servo
that will be the high-pressure helium valve for my rocket:
http://www.watzlavick.com/robert/rocket/rocket1/photos/dsc_1174m.jpg
Thanks again for all the suggestions.
-Bob
On 08/04/2015 06:47 PM, Robert Watzlavick wrote:
I need to tap some #4-40 holes in an SS 316 valve body (Swagelok SS-4P4T) for a bracket. I'd really like to avoid breaking the tap so any tips? I usually use SS 304 and aluminum so I haven't worked much with the harder stainless steels. The tap is HSS and I was just going to use Tap Magic for the cutting fluid. If I have to, I can drill all the way through the body and put a nut on the other side but I'd rather use a threaded hole.
-Bob
