I decided to reuse an existing housing. The LEDs are 5A bin and I like the color much better than the cool white. The battery is 7 x 18650 and the driver is an eval board from National Semi. The LEDs are wired 6s2p and driven at about 500ma per die. Optics are EVA-D and unfortunately the beam isn't quite as tight as I expected, partially due to misalignment. It still works quite well and has survived several dives to 50m with no signs of leaking.
Nice project. The internal threading and using the 4-jaw for offset work shows good machining skills as well - nicely done
Friendly tip - when holding stock on the chuck, to prevent marks on the finished surface, wrap two layers of 3M blue painters tape, like I do here - you still get a good grip on the stock material, but at the same time protect the finish:
Thanks, Will. I've seen much of your work and appreciate the comments.
Unfortunately the real error was a lack of patience, not tape. I wrapped the part in a few layers of kapton tape, which I think should be even more cut/tear resistant than painters tape. When the work is off center though, two of the jaws have a line contact rather than something approximating a face contact. Even the seemingly light pressure I applied sliced through the tape.
I may make a small threaded mandrel to hold the light head for a cleanup pass. There's a small lip on the ID that could be used to hold it, but this is dangerously near the o-ring surface. Or perhaps I'll leave it as is. Some people are more likely to believe it's homemade with a few imperfections.
Gotcha - I see what you mean. Yes, the Kapton tape is way too thin for this use, but is is harder anyway while doing that particular operation on the 4-jaw chuck.
The mandrel idea is a good one. I do something similar for the deep tailcap mod I offer in the 1xD custom bodies that I sell. In that case, not even tape helps, since the splines run parallel to the tailcap, so as you apply presure on the boring bar, the tailcap slides from under the tape. If you apply even more pressure on the chuck's jaws to prevent the movement, then you go through the tape and damage the finish on the tailcap, so I made my own "collet"/sleeve, from plastic, which solves the problem of holding the part tightly without maring the surface of the part (the sleve has a small shelf on the back to prevent the tailcap from sliding further into the chuck). I have one for the "D" and one for the "C" tailcaps, but that is because I do this mod often enough to have a "fixture" for this operaiton:
