On Fri, 19 May 2017 12:00:01 -0400, time-nuts-request@febo.com wrote: > Re: [time-nuts] Machining some aluminum help! It's much easier to use thread-forming taps in aluminum than thread cutting, and the threads are far stronger. Blind holes are not as large a problem. Lubricate with soft wax, not Tap-Magic. Also, why 4-40 in a 0.25" thick wall? A larger screw will actually be easier and again, stronger. .<https://www.mcmaster.com/#thread-forming-taps/=17p2qoh> .<https://www.mcmaster.com/#lubricant-stick-wax/=17p2rpl> Joe Gwinn