I’m interested.
Interested in XHP board for Q8
Interested in dual XML / XHP board, I am thinking in using maybe a SST-40 as first mod and later an XHP led…
Interested for a quad XML footprint board
I would simply like an original MCPCB to try out some other LEDs that will fit the original footprint. Even if supplied assembled, I could easily find a use for the surplus LEDs.
Alternatively I have a simple plan involving a disc of copper with four 16mm holes in it, into which x4 standard 16mm MCPCBs should fit, and all sandwich up nicely into the head.
Actually the big disc with holes might not be necessary, given the way the reflector now bolts down onto the shelf, in the latest version. Just four standard 16mm MCPCBs and some suitable emitter centring rings.
I’ve done this before with an SRK (though it was a crappy one with no shelf, so there was a big additional disc of 2mm copper involved, and some more soldering of bits onto each other, but it all worked out rather well in the end).
Otherwise not sure where this is going, I think I might have suggested a dual footprint MCPCB way back when, for the original torch, but I think that the time has perhaps passed for that.
It will be hard to fit 4x 16mm boards in 38mm pcb place. They will probably fit without cutting, but this way they will sit with wrong center to center size.
I haven’t dismantled my Q8 to check precisely, but it does look as if it has very similar LED centre to centre dimension as my “shelfless” SRK clone, which is 16mm, along the sides of the square.
If so, four 16mm MCPCBs would fit the reflector, butted up next to each other.
Four 16mm MCPCBs fit inside a 38.7mm circle, so at worst only a tiny bit of filing would be needed. It seems they might be a rather good fit.
There is the question of the two screws bolting the reflector to the shelf in the Q8, second version (or the MCPCB to the shelf, in the first version). I don’t know whether they would be clear of the MCPCBs, or perhaps holes might have to be drilled through for them, or they could even be discarded and just the centre screw hole used, with a washer between the screw head and the shelf.
^
The worst part would be grinding the reflector to make room for all the leads.
Leds are placed on 23.5mm circle. 23.5+2×(16/2)=39.5mm.
You are right, small filing would be enough.
I havent check another condition.
16mm noctigons are actual 16.3-16.5mm diameter. This means there is no place for “walls” in your copper plate, i.e. you will need to file board from 3 sides and anyway they will lay side to side without any place between.
No place for walls, no place for outside ring, no place for inside ring (wires hole). Seems that your plate should consist from 4 spare pieces.
I don’t think a plate is needed at-all.
I only needed that for my SRK clone, because it had no shelf. I should say I had access to good machinery then, so just milled x4 16mm butting holes into a disc of about 4mm copper, to the depth of the MCPCBs thickness, and thinned out the edge so that it replaced the original aluminium MCPCB precisely (approx. 45mm diameter and I think roughly 1.5mm thick if I remember). It certainly worked well thermally, bonded in with some Arctic Silver, and the individual LEDs on their MCPCBs could be swapped readily.
I could do the same again by hand, for a hollow bodied SRK, with a lot of drilling, filing and soldering together of copper pieces into a sandwich, but that shouldn’t be necessary for this suggestion.
Yes, it could be a little fiddly putting the pieces together, four MCPCBs to align before tightening the screw(s), a 38mm MCPCB is obviously preferable, if it happens. But I do think x4 ordinary 16mm MCPCBs even ready built with LEDs flowed on, could be fitted OK with a bit of ingenuity, nothing else needed except centring rings and some imagination.
Anyway, just chucking the idea out there for those who do want to try some different emitters, otherwise we are currently a bit stumped, aren’t we ?
23.5mm pitch circle, divide by root 2 is 16.62mm LED spacing at reflector, so they should fit, with just some small filing of outermost edges. Where did you find the 23.5mm number ?
FYI, I calculated, based on LED spacing of 16mm, and MCPCB diameter of 16mm, that they would all fit inside a circle of diameter (16 x root2) + 16 = 38.63 mm.
Depending on actual MCPCB diameter and diameter of recess for the original MCPCB. You say Noctigons are a little over-sized, but maybe some alternatives are not. Either way, a couple of strokes with a file should get everything sitting snug.
I found them in drawing files found in Q8 model archive shared by Miller.
We had ThorFire expand the width from 36 to 38 mm in order to fit 4 16 mm MCPCB's, so it should fit - measured it all out myself I believe. Issues will be wiring and the stacked height.
If this new board can be done for the XM-L footprint it would make things so much easier.
I fitted 4 SST-40’s into mine using 20mm SinkPAD gen 1 boards, but it was definitely not easy! I opened up the emitter shelf to the point there is almost no step left, and in so doing I also dropped the shelf height about 1mm, so I had to also drop the lens shelf and also cut the end of the head for the bezel to seat deeper. Wiring it wasn’t super bad, but that’s largely because I also stepped the reflector on the lathe. This easily allowed the use of 22mm ground wires on the periphery, I used 2 new holes on the outside edge of the new emitter shelf region to bring the 4 individual wires into play. I placed the SinkPAD’s such that all the positives were in the center, this let me make a small copper sheet to cover them and drill a via into this sheet for a single 18ga lead to make positive contact. This fits up inside the reflectors bored out center section.
I used Kapton tape on the bottom of the reflector to ensure no shorts, opened the reflector’s emitter holes so the full substrate of the SST-40 fits inside. It was a lot of work, broken up watching some of the game and two trips to the lathe.
Ultimately, it’s very worth it, with 11,247 lumens at start on freshly charged Sony VTC5A cells with copper button tops added.
Obviously, having the lathe changes how I do things, would have been more difficult with more hand filing of the MCPCB’s but still doable using the 16’s versus 20’s. 
I was thinking SST40 could be reflowed onto the stock mcpcb. I guess the pad sizes are different?
The SST-40 has a XM-footprint.
Dale, that is an awesome amount of work, and turning out the head to fit, and the reflector, was never on my RADAR.
Much respect.
Might have been easier starting with e.g 16mm MCPCBs, maybe also a Dremel, but I wasn’t there.
Very interesting.
The larger MCPCB’s allowed me to keep the negative leads out at the edge of the reflector, there was room there in the reflector design for me to cut it back some at the base for clearance. That’s always the nice thing about a designed MCPCB… the pads are put where there is clearance, in this case they made a recess in the middle of the base on the reflector, which I also put to use with the positive wiring.
I intend to make a final cleanup with some alcohol, seems a couple of the domes caught some dust, so I’ll try to get pics inside it… The white epoxy (Arctic Alumina Thermal Adhesive) coats the contacts and the positive set-up but it should still be pretty obvious how I did it.
A 10” double cut bastard file made fairly quick work of the mating of the 4 SinkPAD’s, kept it square and flat in the process. 
Edit: My Proxxon sees use sometimes, as do most of my other tools, so I haven’t abandoned the old styles due to the lathe. Sometimes it’s simpler just to take care of things by hand, sometimes it’s enough work to be worth going out to the shop.
One thing I’ve learned to do that might not appear obvious when modding a light, when I intend for the reflector to sit on the MCPCB and surround the substrate of the emitter, I cover the base of the reflector with Kapton tape. When I cut out the openings I don’t cut it flush with the opening itself, instead I cut it about 1mm inside… this leaves the Kapton tape slightly over-covering the hole. In this way the substrate pushes up into the hole of the reflector with a Kapton separator, to avoid a short on the substrate itself. I learned that on the big MT-G2’s and now do it with anything that might touch the reflector.
The trick is to cut the hole where the overlap is just barely more than the height of the substrate, so it doesn’t interfere with the die or show up too much in the reflector and effect the beam. Educated guesswork, 