What is AA MiniMag Tailcap Machining?

[Dave Wright]

I'm thinking about doing this myself versus having a machine shop do it, but don't want to waste money by getting the wrong tooling. The 2 bores appear to be 9/16" and 5/8". The thread measures 5/8" x 32 on an old tailcap. The thread measures 5/8" x 28 on a new Kroll tailswitch. Neither thread section was long enough to measure accurately. Can anyone tell me the correct tap? Thanks in advance!

 

[McGizmo]

5/8x28

- Don

 

[Rothrandir]

please, tell us what you're doing /ubbthreads/images/graemlins/grin.gif

 

[Dave Wright]

Thanks guys! I got the note from Wayne yesterday that my MadMax shipped. Time to think about fabrication. I'm going to cut down an AA Minimag and see if it can run the MadMax. My goal is half the light output of the 2xAA setup but the same runtime and good regulation. I'm hoping that the MM can be dialed down to about 150 mA output to accomplish that. From what I've read, my results will depend on the LEDs Vf and my battery choice. Low Vf + LIthium AA might = good result. High Vf + NiMH might start dim and fade fast.

Pretty low tech compared to the great stuff posted on this site. It might be a good EDC though. More later.

 

[Rothrandir]

sounds nice!

 

[tvodrd]

Dave,

The batteries are expen$ive, but you could turn the MadMax up and run the stripped 3V AA size liths out of CRV3s. I cut the head down on this one, and made a press-over piece to hold the optic and lens. Has a BB500:
Edit: You can probably get the best price on a 5/8-28 plug tap at Travers Tool https://www.travers.com/index.asp - search cat #14-040-282 ($14.08) You will have to drill the I.D. larger before tapping.

Larry

 

[Dave Wright]

Thanks for the idea, Larry. I may try that after getting the basic setup going. I like Travers because one of their few "storefront" locations is nearby. Reasonable prices on arcane tooling, almost always in stock, and I get to handle the goods before pulling out the wallet. Is 9/16" the proper bit to run in before tapping the 5/8-28 threads?

How did you make the head on your light pictured above?

BTW, I'm something of a cheapskate but I would LOVE to have one of your tiny new 1x123 lights. Does the LED have a good metal heatsink path to the aluminum body? It looks like maybe the LED is surrounded by epoxy.

Best Regards.

 

[tvodrd]

Dave,
Without doing some calcs, 9/16 should be OK. The head consisted of turning down a mag head while chucking the body. (A 4-start thread is a terrible thing to waste /ubbthreads/images/graemlins/grin.gif ) I then made a piece to press over it which included a slightly turned-down optic and a glass lens. There are no seals- it aint watertight. (Bright little sucker, though.)

On the little 123s, the LED is Arctic Alumina-epoxied to the copper centersection- good as it gets (I lapped the diodes!) The threads are bare metal contact to the body, and the whole thing(s) warm-up quickly /ubbthreads/images/graemlins/grin.gif . The human hand/ blood circulation reaches equilibrium at a not uncomfortable temp. I don't know if it would overheat if you just set it down. After initially bonding and soldering the LSs, I did pot the connections, just for mechanical security,

Larry