That's a whole lot of shavings you found inside that 3.25" round stock.
Looks like it's going to be a very sweet, but serious light. :)
I can’t wait to see a beamshot from this thing. 40watts+ from an XP-L size in a Courui reflector… Wow
Great work. Look forward to reading about the end result.
subscribed!
i wish i had a lathe! 
i learned to work with them - but have none to use if i have an idea.
so it takes looong to build something from old parts than just making what i need….
Nice. I feel for you when you mentioned boring a large hunk of aluminium out taking all day. Even turning the outside would be a marathon effort. Thanks for the update.
Nice!
Do you have a closeup of the driver? What did you change to make it run at 4s? What firmware are you using?
Great to see another of your creations! I love knurling. Just love it.
Nice work! The knurling looks spectacular and I can’t wait to see the final product.
You might consider running 26650 LiFePO4 cells to reduce the power slightly and have less voltage sag. I did that with direct drive on 3 XHP-70’s with terrific results, over 15,000 lumens.
Also looking forward to seeing what this XHP-35 does at those levels. I have components on the way to use with an LD-2 for a build I’m doing with one of these emitters, should be here today actually. I was planning 2A but now I might go a little higher… 
Thanks for sharing, and for the words on Josiah. 
The way that knurl is created differs from most lathe work. Rather than cutting maternal away, what your actually doing is "pressing" the design into the metal. Doing so will actually increase the diameter of the part due to the peaks made on the knurl.
The hard steel wheels on the knurler have lines in them in opposite directions.
Typically you center the part between the two and run an "X" pattern on the part, but I have found I get better results ( especially on a long part) by running one wheel and then the other.
A close up of the result.
The driver is my version of the BLF DD FET driver. Here is a link for the boards and the parts list needed. If you use the parts for the standard 8.4V config with the zener diode etc, the only thing you need differently than what is in the list I provided is to change the 10uf cap from a 10V to a 16V.
17mm & 20/26/27mm single-sided DD/FET driver release: A17DD-SO8 / A20DD-SO8 / etc
RMM has some 16V 10uf caps and his boards may be 16V ready, but I dont know for sure.
I am just using the star off time firmware for this.
Nice work. The knurling looks fantastic.
Thanks for showing how the knurling is made. The tool and the knurling you created are just too 
. Sure seems like it would take a lot of pressure and consistency to get it right.
WOW!! Fantastic work! Thank you for sharing VOB. I dig the Grizzly
Excellent work really and it was interesting to read how knurling is achieved too. I wondered how it would be done in simple manner. I’ve never used a lathe but I can see how useful it can be for such work.
Another knurly beauty from VOB’s workshop. Looking forward to more lathe, and tooling info… very interesting.
Coming along nicely!
Quite a large update added to the OP. Including LUM 5-90 and more on the head.
Gr8 build man! Your reign has started!
looking good!
I like the reverse tapered head. I dont think Ive seen that done in a light of that size before.