New Peak Eiger.. Safe to grind down brass contact to help battery fitment? (pictures)

[combinatorix]

Hi all. Just recieved my new neutral SS Peak with QTC in the mail from Bob today! Very pumped, I LOVE the QTC operation, and ramping is especially smooth with non-alkaline batteries.

I have some 10440 cells in the mail, but currently have been trying some different AAA cells. The trouble is, with most of these cells the o-ring is slightly exposed in the off-position, and to cover it up any more results in turning the light on. This is a little bothersome, and since I found the threading can theoretically close up to .100'' past the o-ring groove if in fact the battery tube spacing was better designed.

Now my question is, is it safe to grind down the brass contact on the head? I measured the contact protrudes about .020'' from the epoxy, and if I took even .010'' off I could greatly improve the situation for a majority of AAA cells. Also, is there any other modification I can do short of machining a new body to give myself some more room for the battery?

Pictures to follow...

O-ring Issue is particularly evident with an Energizer primary lithium cell:


Part of head I would like to shorten (maybe down to the bottom of the letter N?):


My brand-new SS light with my brand-new SS knife! New EDC gadgets? You bet!


EDC duty for the past 2 years (keychain duty has not been kind to hard anodizing)

[fyrstormer]

I do the same thing on all my Peaks. It's safe, but if you use a motorized grinder you MUST do the grinding in short ~3-second bursts and then quench the brass contact in a cup of water, to prevent overheating the brass contact and breaking its solder joint.

[combinatorix]

Thanks for the go-ahead! Since it is such a small nub, I just spent maybe 5 minutes taking it down with a jeweler's file, then sanded it with some 1500 grit to clean it up a bit. The "N" marking is gone, but the battery fit is very clearly better! The body can now make it ever so slightly past the edge of the groove without turning on even with my longest cell, which was the basic necessity.

My longest cell happens to be an energizer lithium primary, which for whatever reason seems to ramp much more smoothly than the alkaline cells. I don't know if it's a function of the cell chemistry vs. draw rates but the alkaline definitely seems to have a jump in the middle of ramping, while the lithium is constant.

Can't wait for the 10440 cells to show up

[cave dave]

Seems like this is a common problem. I think Peak needs to go back to the drawing board or have a better QC department.

I just got my Eiger hiCRI QTC yesterday and am having the same problem as others except mine is the lug version so there is nothing to screw down. I measured it and the body itself could be 2.5 mm longer with out bottoming out. Even on full output I can still see the O-ring grove. I tried every brand of aaa battery I owned and they all seem to be the same length and have the same problem. (Eneloop, Rayovac hybrid nimh, Duracell primary, Li L91)

I don't think there is enough nub there to grind away 2mm is there? The problem with the QTC is that it likes to turn itself back on after you turn it off as the QTC material itself uncompresses over the course of 10 seconds or so. So you really need some extra threads to work with so you can give it an extra half turn to ensure its off.

I really don't look forward to dealing with Peak customer service, I've done it twice before and both repairs took longer than 3 month each with terrible communication, and that was back when they still answered their phone. I've gotten faster service roundtrip to mainland China.

I guess this will likely have to go back, what a disappointment.

[combinatorix]

Seems like this is a common problem. I think Peak needs to go back to the drawing board or have a better QC department.

I just got my Eiger hiCRI QTC yesterday and am having the same problem as others except mine is the lug version so there is nothing to screw down. I measured it and the body itself could be 2.5 mm longer with out bottoming out. Even on full output I can still see the O-ring grove. I tried every brand of aaa battery I owned and they all seem to be the same length and have the same problem. (Eneloop, Rayovac hybrid nimh, Duracell primary, Li L91)

I don't think there is enough nub there to grind away 2mm is there? The problem with the QTC is that it likes to turn itself back on after you turn it off as the QTC material itself uncompresses over the course of 10 seconds or so. So you really need some extra threads to work with so you can give it an extra half turn to ensure its off.

I really don't look forward to dealing with Peak customer service, I've done it twice before and both repairs took longer than 3 month each with terrible communication, and that was back when they still answered their phone. I've gotten faster service roundtrip to mainland China.

I guess this will likely have to go back, what a disappointment.

I was able to mostly alleviate my issue by grinding down 0.3 to 0.5 mm. You could grind below the epoxy but I don't know how deep that brass contact goes, I wouldn't try it unless someone can confirm that you aren't going to lose your entire contact point.

It would astound me if the problem lies in the machining process of the body. I am convinced it has to be either a design flaw or quality control issue relating to the actual length of QTC pill and what Peak thinks it is.

[fyrstormer]

I alleviated the problem of the too-short battery tube by shaving the brass contact and then removing the QTC material and soldering the two metal halves of the QTC pill together. That also reduces friction in the threads because I'm no longer cranking down on the head to compress a little piece of rubber inside the QTC pill.

Also, as far as I can tell, the QTC material compresses permanently over time, and the QTC pill is only designed to accommodate its original thickness, so as the QTC material gets thinner, you get less and less ramping before the two metal halves of the pill contact each other and turn the light on full brightness. QTC is a great idea, but the implementation leaves a lot to be desired. I think it would be better to use it inside the head, as a pressure-sensitive current-control resistor for a constant-current driver. That would require a more intricate head design, though.

[combinatorix]

Got my AW 10440 cells today, they fit well (a little shorter than an AAA I believe) and the thing is a keychain MONSTER with them.

Too bad the QTC doesn't last forever. Do you have any idea how long it lasts? If I only had to change it now and again I wouldn't mind given the natural UI and efficiency. Also have to figure out where I can buy a stockpile

[fyrstormer]

I don't know that the QTC doesn't last forever, I only know that the Peak QTC pills are designed around its elastic properties when it's brand-new instead of broken-in. It might be possible to make the QTC pills work better as the QTC material ages by sanding the inner surfaces of the metal halves of the pill, so the broken-in QTC material gets squeezed harder before the metal halves come into direct contact.