I realize that I haven't actually posted some photos of how the battery tube was made on the lathe, so I'll show some work on the head of the light, to make amends.
Here's the end of the head where the battery tube will be attached. I've prepared the area to be threaded--the flat area ahead of the threads is for the O-ring landing--the O-ring being held in a groove on the battery tube, of course.
The treads have now been machined--they are 0.5mm pitch.
And the final check on those threads, to ensure a smooth feel to the threads. I never check my threads with gauges, since I always have the mating part on hand--and how they work means more to me than whether I cut them to spec or not. :devil:
The start of the exterior machining--the head has been placed on an expandable collet and that collet sits in a rotary indexer. So the cutting operation is basically milling. The cutting tool on the left is brought into the work to a specific depth, the part is rotated 360 degrees to cut a circumferential groove. Then the tool is advanced a bit more, the rotation repeated and then the final depth is reached in the third iteration. These are the easier cuts to do, they just take a long time.
And now the axial grooves are being machined. This is hardest operation to do perfectly. The placement of the cutting tool along the axis is not exactly where the circumferential grooves were machined--the width of the flat between the grooves is 0.127mm, so the beginning and end measurements are either increased/decreased by 0.06mm to ensure that the cutter does nor mar the circumferential grooves' surfaces. With each section having four cuts, and with five sections around the circumference, that means twenty cuts, each of which require three passes to get to the right depth--so a total of 60 cuts just for one section, and a grand total of 180 cuts to complete the head.
And did I mention that there were three sections on the battery tube, also? :shakehead
A trip to the buffing wheel to take some of the sharp edges down a tad, then to the hot detergent wash to clean off the buffing compounds before posing for the camera.
Front of the light on the left--showing the bevel to the lens.
Close-up shot.
Overall, I'm pleased with how it is progressing. The light bouncing off the pyramids when turned in your hand is quite entrancing, actually.