That is what makes the sk68 much better! And nicer than the c78 I think. Lumatic had a go on something like this a year ago, but you did it more thoroughly.
The knurled middle part is actually slightly narrower now that the original SK68. i machined the SK body down to a smooth tube, then re-knurled the body area.
Damn, i which I own the right amount of toys…errr…tools to do this al for myself!!!
(once when I worked at the Federal Institute for Materials Research and Testing they had a sweet machining shop! Damn I was thinking about an “internship” there…)
Pre ’84 or ’82 all copper penny, sand smooth, drill small hole in center, put on dremel cutoff wheel tool or harbor freight one, spin and grind off diameter on sandpaper or hobby file till it fits in the pill, epoxy/RTV down, then epoxy/RTV the emitter base to that
Or cut out a plug from a sheet of copper if you can find some
I retrofitted a larger zoomie this way, even went so far as to solder/braise the copper disk to the copper sink pad (line up wire holes, put solder paste between, drop in stainless frying pan, apply heat till solder melted), then reflow the XM-L emitter off the aluminum one (same process as above), went from 1.4mm aluminum to a little over 3mm thickness of copper, also brought the led almost flush with the pill and touching the bottom of the aspheric lens in unzoomed mode, a MUCH larger flood pattern
lol you read my mind. that is what i used, was an old Canadian penny, with the surfaces sanded smooth on a disk-sander, then spun-down to fit the SK body, then with holes for the wires
Nice work on the inside too, I have done similar 'inside jobs' on the sk68 too, to fit various drivers, with the last one I grinded a few mm from the underside of the pill and fitted a slice of 17mm copper piping between driver minus ring and pill to avoid the component getting squashed by the pill.
Fun to see one of those blf-mini drivers again, I thought I was the only one using them every now and then in mods.
(off topic: I have a spare LuxeonQ led if you are still interested, see my thread)