43? 44? Does it vary from one board to another? Your board may vary?
The pictured one has straight cut lines next to the screwholes ……
I hate seeing circular pie charts depicted at an angle.
Yes 
. 43 on the flats, 44 on the full round diameter. I'd assume he's looking for the 44 number.
Ok - did some investigation of this and can easily reproduce it, though not every time. It is a bug for sure, I wouldn't consider it a showstopper, but unintentional behavior none the less. No harm, but the LED sometimes is left on after an LVP drop, and is not blinking the way it should be. The "bug" is that I'm trying to control the switch LEDs from multiple places so it's getting turned off quickly after turned on, and left on when it should be left off. It's a timing thing, so has sort of a random pattern - sometimes left on, sometimes left off.
Writing it up and should get it fixed in the next release, hopefully in the BLF GT -- think we still got time to update the firmware.
We’re both right. Lexel measured inside of battery tube, I measured pcb from flat to flat.
I measure Battery tube = 44.8mm.
Bug?
Hey, when I leave the Q8 flashlight on outdoors at night, I notice bugs are attracted to it.
I would prefer brass for tail plate.
Screws material is not important. Solid wire is not proper material for screws. Bare copper rod can have different mechanical properities, for screws you need hardened copper, while wire copper is made softer with annealing to allow bendings etc.
What’s the recommended thickness of the wire for spring bypass?
It pulls 20~ 23A
At 24A that is 6A per spring
So minimum of 22 guage 
Bigger guages mean less resistance but harder to work with.
Cheers David
Edit:- spelunking
I use 20 AWG after pulling the inner spring to make room. 22 AWG should work, probably very little difference, if measurable.
Thanks! :+1:
Regarding the Q8 turning off from a bump:
As I was getting ready to do the spring mod, I read about the how the Q8 will turn off with a fairly soft bump. My question is: instead of using 22ga stranded wire, is there a reason solid copper wire could not be used? It seems that might add quite a bit of stiffness to the Springs-is there a heat or resistance issue or any other reason this would be a bad idea? Thanks,
Ed
Bypass wires should be flexible and fatigue resistant. Multi-stranded, or braided.
Using a stiff single conductor copper wire would, long term be more likely to fatigue, crack, fail, maybe un-noticed.
To stiffen the springs for bump resistance, additional or replacement steel springs are the probably the best material, and once bypassed their poorer electrical properties don’t matter. I think there have been suggestions about better stiffer off-the-shelf springs, certainly the standard soft ones are not great in resisting bumps, and it also seems the stock inner springs are also ineffective electrically, and contribute little to “springing” either.
I’ve even been thinking about making an elastomer cone, or injecting one using e.g. silicone RTV, to fit inside the springs, stiffen and damp them, but that is just a (whacky) idea of mine.
> making an elastomer cone, or injecting one using e.g. silicone RTV
Hot glue? That would preserve the “fuse” function of the springs, collapsing when they’re overheated by a short circuit/battery in backwards
Thanks Tom. I really love my Q8(and have two more coming). I really appreciate being able to ask a question that some may consider ignorant and receive an educational answer, especially so fast. I love the Narsil UI so much I also have an Emisar D4 & D1 en route.
I am one of the relative newbies that lurked for a while & joined to participate in several group buys. I have never been disappointed. Despite all the uproar over the Cometa, I have two and use them when a zoomie is needed. After a few minor corrections I found reasonably easy to do, there has never been a problem!I am very appreciative of all the efforts it takes to come up with a concept, develop the idea and see it all the way through production. And at a cost so low it probably would not even cover the cost of the r & d, much less through prototype and production models. Thanks to The Miller, you and the team for all your work.
Ed
Certainly not. Elastomer. With non-linear spring stiffness and internal damping. Think “bump stop” in car suspension.
But a cap. across the MCU supply is the simplest solution, gets to the root cause, at least for me.
Maybe this? (oogled: “hot glue” elastomeric)
silicone elastomer hot glue (product name: HM-2500) produced by Dow …
Not my thoughts. RTV silicone either cast into e.g. a plasticine mould, or even a dollop injected inside the springs, out of a squeezy tube. A way of beefing up original weak springs with something some of us may already have lying around.
But it is an off-the-wall idea, not one I intend to pursue myself.
Today I made a 43mm*2mm copper disc. That one will probably work.
I do have some 2,5mm brass sheet here, will try that also.
About that mains wiring, I know that this is soft copper. I tried it anyway.
The screw I tested in a M3 threat in normal steel was quite solid.
The slotted screwdriver tore the head apart, before the screw gave up.
But even that was below 6Nm torque. That’s the smallest torquewrench I can get my hands on.
I will try those screws with some old PCB in a piece of aluminium to see if they will do it.
And thanks for the dimensions!
Hi Flashy Mike, I’d like to reproduce your capacitor mod but as I’m no electronics expert can you give a bit more detail on this mod? Perhaps another picture from a different angle as well? It seems like you have one of the leads of C2 soldered to one end of the capacitor and the other end is soldered to exposed trace in the PCB. Have you kept or removed the original capacitor? Do you think using using a larger or multiple capacitors in parallel would make a difference? This seems like a great solution to a problem I never even anticipated (until you drop it accidentally and then can’t find it even with the switch LED). Would something like this be suitable? http://www.ebay.com/itm/10pcs-1206-107Z-100uF-16V-chip-SMD-Ceramic-capacitor-/292207189605?epid=2163346082&hash=item4408e7de65:g:AZEAAOSwcB5ZHHEp
My thought on the switching off on bumping issue is that continuity need only be maintained on one battery to prevent it, so perhaps something added to a single spring, or a thick magnet at the negative side of one cell would work?
Would anything be practical at the positive side?