It’s 6061 T6. It’s all about the temper.
Looking sharp Dale!
Hopefully you’ll feel better soon to polish out the latest minor scratches, but still, looking good!
Turningbluechips, When and where can we order it? 
All my aluminum I machine lights from is 6061-T6 from online metals.com, complete with certification sheets. The only aluminum I’ve found as hard as this is a piece of 7075 I used to mount a sheet of Titanium when I re-created the plate they screwed to my spine. I’ve got a 55gal drum full of 6061 T6 shavings, I’ve worked it by hand quite a bit too, this just seemed much different, much more resilient.
Edit: Glutton for punishment that I am, the bracket polishing got me started and after lunch I got busy with a piece of Titanium… the presentation side of my SpydieChef! 
Had to flame it when done polishing, of course…
If only Aluminum were as easy to anodize…
You’re probably used to finishing parts you have turned. Just the heat from turning will soften the metal quite a bit. There is no heat with the waterjet.
Sink a drill bit into it and you’ll quickly find out it’s not 7075. That stuff chips up. This will make strings.
I was making stuff for lights by hand quite a while before the lathe came my way. Used to hack saw off a chunk from bar stock, drill it and tap it, mount it to my drill with a bolt in the end and spin it up (very slowly) using the cordless drill, carve off what wasn’t staying with a rotary tool in the other hand. Or file it down and sand it, no heat at all. The Old Lumens way.
Regardless, I was surprised at how tough the material for this bracket is.
My first real experience with 6061 came in the form of a 1/2” rod 2’ long that I was going to use to make a video rig for my camera. I figured I’d bolt it to a 15” car wheel and bend it around the wheel to form a curve. Ended up using a 12” handled 8 lb sledge and about 30 minutes of hard labor to force this skinny rod around the 15” curve, flat couldn’t believe aluminum could be so dang strong! And no real hammer marks on it either, in spite of the furious pounding I gave it with that little sledgehammer head. 6061 or not, either way the bracket is probably stout enough to break the 1/4” bolt, wouldn’t surprise me at all.
I know this is a old thread but did these ever go on sale? If so where and how much? If not I’ll just draw one out and have my water jet guy cut me one real quick then i will turn me a handle real quick. Just too many other projects and looking for a quicker option. Looks great.
I’d like to know that too
This thread pretty much faded into oblivion. I was really interested in one of these last year. Are they for sale?
It just kinda stopped all of a sudden. No mention of where this idea went. It seemed like a good one. Nice design. Functional.