Is there such a think as too many M6 threads?

I doubt it

Mostly I just had to share with everyone that I just received an M6. I blame the generous CPFer who bought me a 6P a few weeks ago, if I had never drank the SureFire Koolaid I'm sure my wallet would be a lot thicker right now!! haha...

I picked up a brand new one from Generic808 over on BST@marketplace (Thanks!). For that price it was hard to refuse, and after thinking about it, It only makes since that I own the flashlight I am making battery adapters for- of which a lot more sold than anticipated very quickly... This gives me a platform to work on more projects from. I already have an idea for some other possible adapters, so I can technically write off the M6 as a business expense which made it a little easier to justify, add to that my wonderful wife actually wanted me to buy it for myself, provided she gets to play with it once and awhile!

On top of that, Emoli cells arrived at the same time today! (Thank You LuxLuthor!)
I'm running the MN21 on the Emoli cells, not with a full charge though, I've also got an order in with digikey for an assortment of NTCs to try out.. My feeling being that the MN21 is going to be really taking a beating on these cells. Even in daylight I can visually see it's running a lot whiter and brighter than it does on the stock CR123 pack.

Today feels like christmas morning when I was 5 years old!



Any thoughts on those NTCs? I ordered a bunch of them, ranging from ~6A-10A rated, with everything from ~1-2 ohm initial, up to around 10-20 ohm initial. The running resistance on em is ~0.1-0.3ohm. I was thinking about trying the higher resistance versions first and see how that works, My concern being that the lamp may start-up too slowly, not sure though, it'll be an interesting experiment! They should be in before the end of the week.

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One question for M6 users... Are the tail-cap threads normally kind of noisy? I lubricated them slightly more than they came and that helped, but they are definitely noisier than most of my flashlights, they do run smooth and true, just with more noise. They seem to be getting quieter as I play with it.

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I'll probably share some more initial thoughts on the light later tonight, I'm very anxiously waiting for darkness, it just can't come soon enough tonight!

Eric

[edit in]
Could I ask for a better day?!??!?? We got some FOG tonight!
Here's some beam shots:
for comparisons sake, a "290" lumen R2 drop-in in my 6P


A ROP high on eneloops


The M6 MN21 on Emoli

Hello Eric,

I am glad to see that you are finally the proud owner of an M6. Congratulations.

I am looking forward to reading your thoughts about it.

Now you need to get to work on a 3x17670 adapter for it.

Mdocod, a respected CFR´s like you until now with an M6!!

Congratulations and welcome to the M6 club. The M6 is my favorite Surefire along my A2´s.

mdocod said:

...my wonderful wife actually wanted me to buy it for myself, provided she gets to play with it once and awhile

Click to expand...

How good is that!

About NTCs - I have used a lot of them, mostly in sealed-beam projects, and here are my own 2 rules of thumb:

1) only required if you are overdriving.

2) Start with the likely resting pack voltage, and subtract the normal, rated bulb operating voltage. Divide this by the normal operating current, and this gives you the cold resistance you want in-circuit at switchon. Select the next-highest NTC value.

An example will help. I plan to run a Q4509 from a 4.2Ah 14-cell NiMH SubC pack. A Q4509 is rated by GE at 100W @ 13V.

Assume the pack is freshly charged and can deliver 1.3V per cell under load - 14 x 1.3 = 18.2V

Subtract 13 from 18.2 = 5.2V.

Normal rated operating current for the Q4509 = 100 / 13 = 7.7A

Divide 5.2 / 7.7 = 0.676 ohms.

A 1 ohm NTC will do the job. So would a 0.68-ohm NTC, if such a thing exists. But I wouldn't go higher than 1 ohm, though. Definitely don't exceed double the calculated value.

Since the resistance of the NTC at 8A or more is very low, the hot resistance takes care of itself.

The only word of caution I would advise with the M6 is that, looking at the Lumens Factory catalogue, the bulbs are already overdriven at spec, given their short lifespans. Overdriving them even further, despite the easy ramp-up an NTC will give, will give them a short and merry life indeed...

Hope this helps.

Hello lctorana,

Interesting idea on the NTC there...

Let me see if I have this right...

I can only guesstimate that into the ~5A load of a MN21, an Emoli 18650 would behave roughly like a 26700 Emoli would into a 10A load, Since Silverfox has a chart of the 26700 up, but not the 18650, this is the closest estimation I can make. With this assumption, I can expect fresh off the charger voltage of ~7.5V at the pins, possibly a little higher, I'll probably try to terminate charging to 4.10V per cell to reduce problems...

So lets say that I'm expecting a loaded operating voltage as high as 7.5V, and I'm going to assume the MN21 is "specced" at 6.6V, then that's 0.9V / 5A = 0.18 ohm.

The cold resistance of an MN21, is, well, apparently difficult to measure, lol... It seems to be bouncing around on my meter as I try to measure it, but it seems to be about 0.5ohm. Or basically, Adding 0.18ohm to this would still result in inrush currents approaching 10 amps. (I think).. But it does seem like a 1ohm would do the job quite well, in fact, it should have an inrush current limited to about 4.66A, which would be below operating current, of course it would heat up and settle "up to" 5A steady state very quickly....

But I couldn't help but think, that adding a nice chunk, like 10 ohms at startup, would not just help suppress the inrush current, but also act as a true soft-start, maybe even drawing out the start-up time by a noticeable amount. This way the temperature change at the bulb would occur more slowly, less shock, maybe better bulb life that way. what do you think?

Eric

Grats on the M6! You deserve it!

The threads on my m6 are silky smooth and quiet. In fact I ordered 2 tubes of nyogel today because I was so impressed with my M6 threads that I decided I want all my lights to feel like that.

(Most of my SF's were BST with who knows what, and I replaced the lube with generic silicone grease)

Mdocod, if this is any help to you, I run my M6/MN21 on 7.5 volts and soft start. This is off a Willie Hunt pulse width modulating voltage regulator that JS used in his marvelous M6-R packs, but Wquiles modified to run from the preset 6.8 volts to 7.5 volts by changing a resistor in the regulator.

So if you will use soft start in your fashion, you'll probably be OK. But I also think the PWM takes some heat off the bulb on a constant basis I'm not sure.

Either way, the MN21 runs awesome I just don't let it run more than a minute on each pulse because the glass envelope will get very hot and start to darken prematurely, even before the lamp fails.

I promised to share some of my thoughts on this light after having some time with it. So here's some initial impressions.

Positive feelings about this light:
1. Looks awesome
2. It scratches keys, keys don't scratch it (I tested it, lol)
3. the finned design at the head of the body and base of the head should help minimize the amount of heat that makes it down into the body while providing some decent heat sinking.
4. Good balanced beam profile, throws with authority, but spreads it around enough to be useful.
5. It's an M6
6. light was in ~99.9% perfect condition new, I was only able to find one very very very minor imperfection on the body on one of the raised knurled bumps of the grip. The rest appears to be flawless. Fine craftsmanship, they've got me beat!
7. The MN21 has a nice beam profile that is very close to round with minimal artifacts. Minor "batwing" look, but nothing noticeable in use.
8. Did I mention? It's an M6.
9. Works with my battery adapter

Not so positive feelings about this light:
1. MN20 beam is hideous on mine, very oblong and very noticeable in use, but does throw nicely. If i install it to match the flats of the body, I can make use of the wide beam, but honestly it is mostly just annoying. This isn't really an issue, if I wanted a setup for runtime I'd probably switch to some AW 18650s and push an MN15 or HO-M3T, but this is an M6! I'm going for output here
2. Tailcap threads are a little noisy, but seem to be quieting down with use and lube. I'll probably try cleaning them up real good and re-applying lube to see if that helps.
3. The Surefire web address on the tailcap seems tacky to me. But I guess they are all that way, on the M6 it's in BIG print so just jumps out seems like kind of an eye sore to me. That's the only visual thing about the entire thing that bothers me.

General thoughts (not positive or negative)
1. Body has some serious girth to it, still trying to figure out how I want to grasp this thing comfortably, I'm still in a love/hate phase of figuring out how to deal with this larger than D-mag body. I'm starting to get used to it. I guess when you think about it, the types of guys who really NEED an M6 in their line of work are generally of the large format body type which would generally coincide with large powerful hand grips, busting down doors, etc etc. I'm not that guy.
2. I'm glad I went with the scalloped bezel. It's perfect. I wanted something that wouldn't interfere much with the spill beams shape, but at the same time, the standard "flat" bezel looks kind of plain. The scalloped gives it some attitude without sacrificing any noticeable spill beam in use.
3. I would have liked it if the texture on the tailcap was of the same depth and intensity as the texture up around the head. Not sure why the texture on the head is grippier and more defined, but it is by a little bit.

That's all I can think of now!

Eric

Good to hear your feelings after some time actually using it.
:twothumbs

Eric,

Glad to see it arrived safely. Now you finally joined the club :wave:

I also noticed that ALL my M series threads are a little noisier than the other series lights, and I have A LOT of M's. Even after cleaning and lubing, they still are not as smooth as say, the P/C series lights :shrug:

But like you said, it's an M6!! What more could you ask for :devil:

-Eric

mdocod said:

But I couldn't help but think, that adding a nice chunk, like 10 ohms at startup, would not just help suppress the inrush current, but also act as a true soft-start, maybe even drawing out the start-up time by a noticeable amount. This way the temperature change at the bulb would occur more slowly, less shock, maybe better bulb life that way. what do you think?

Click to expand...

I think 10 ohms is way too much, because the hot resistance will be too high, and you will sacrifice brightness, even after the NTC is fully warmed up.

Even 1 ohm is a little too high for this application. If it is 0.18 ohms you are looking for, then anything above about 0.36 is too high, IMHO.

Very good thread, and I'm delighted you now have an M6!

It will be interesting to hear how your MN21 lasts on Emolis, and how much difference the 4.1V intead of 4.2V charge makes.

I think your MN20 may be a bad example. It's by no means my favorite bulb anyway, but yours sounds much worse than the ones I've tried.

Congratulations! And, no, one can't have too many M6 threads, provided they aren't just fluff.

So, let's see . . .

No, the threads shouldn't be "noisy". Mine isn't, at least. That said, I wouldn't worry about it. They will probably wear in and quiet down with a hundred or so activations. If not, contact SF CS and tell them about it and they will probably replace your LOTC.

As for the grip and the girth of the M6, give it time. You will need to develope certain hand muscles, which will happen in fairly short order if you use your M6 regularly, and when you do, you will be completely used to the size and feel of the M6, and probably prefer it to a mag body diameter. Or at least I do.

As for NTC's, you might want to talk to Northern Lights about them.

As for the MN20, you probably have a not-so-good one, relatively speaking. The old style MN20's were better in this way, in general, than the new style, but even the old style had a somewhat more squashed beam than the MN21. But the old-style MN20 is my favorite SF LA, along with the MN15 in the M6.

Congrats mdocod, it couldn't of went to a more deserving fella.
Great and informative review, I'ts great to see that over the evaluative period you learnt more about the M6, certainly not something you can read about online.
Your writeup and beamshots are making me think...lol thanks for that. It has more spill than I thought it did.

We can't have too many M6 threads or too many M6s. Everytime I use mine I have a smile on my face. It makes all my other flashlights seem so ordinary and ......... dim.

I'll assume mdocod was joking about the M6 having too many threads. Mine has just enough to secure the turbo head and tailcap without having too many. :laughing:

But seriously folks... isn't the M6 the KING of incans? Our king is a good one and deserves proper recognition on a regular basis.

I'm happy for you mdocod. You surely deserve one of the best lights for all of your CPF contributions.

I thought he meant forum threads on CPF, not screw threads on the light...? :tinfoil:

JNewell said:

I thought he meant forum threads on CPF, not screw threads on the light...? :tinfoil:

Click to expand...

He did.

Eric, first of all congrats on the M6. :thumbsup:

Secondly, the noisy bit I can help you with. I found out that the noise comes from the o-ring not on the body but from the TC end. Twisting the tc, the o-ring rubs in the barrel which is coated with chemkote.
To remove the section from the tc, remove the tc spring, using a long nose/tweezer pinch the plastic clip in the hole and then take out the section. I had to change my o-ring as it has dried up and cracking. If you do change to a new o-ring and it still is noisy, use some cutlery polish to polish the inside of the barrel from the end to about 1" down. This would not remove the chemkote layer but it make the surface smoother for better operation.

Hope the above helps. :thumbsup:

Hey those are nice beamshots. You can actually see the "beam" in them. I was going to add such shots of the lights from that angle. You beat me to it. They have a 3D feel to them whereas the standard shots from camera positon can seem rather flat. Nice job.
:thumbsup: