Fenix TK20 diameter questions for helmet mount

TomInOregon

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I am planning to purchase a Fenix TK20 for firefighting use since I believe the warmer beam and smooth reflector will cut through smoke better than most LED lights. The problem I am having is finding a helmet mount that will fit. I am looking at the Blackjack helmet mount, but I'm not sure the light will fit. The specs show the TK20 with a 34.1mm diameter, but I am not sure if that is the body or the head. I am also wondering if the body under the grip is slimmer all the way to the tailcap (If I take the tailcap and grip off I can slide the body into a mount). Basically I just need the diameter of the body in different locations so I can see what size mount I need.

Thanks,
Tom
 

bikenjam

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the head is 1.34"
handle with rubber grip is 1.01 to .92", slight taper to the last 3rd of the grip then it gets slightly bigger again to .935"
from the little i peel back on the grip(since i glued mine) its .75" at the rear and .88" at the front
tail cap .98"
hope this helps

btw, you might want to look at a lighter 2XAA light such as the L2D, LD20 and so forth. I just picked up a eagletac P100A2 for $42.5 shipped from flashlightconnection.com It has the same UI as the TK20, which is why i bought it, but it is much lighter and a bit brighter.
 
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Foxx510

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I just picked up a TK20 for my father, and I also wonder if it would be too heavy for a helmet. It's a really, really solid little light for it's size. If you do helmet mount it, make sure its a really solid mount or it will move around a lot due to it's weight.
 

TomInOregon

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Yeah, it's bigger than I would prefer, but it's 0.2 oz. lighter than the UK 4AA lights we use now. The length may end up being a problem, but it's definitely worth a few hassles if it cuts through smoke better than our current lights with better run time. Thank you for the measurements. That's exactly what I needed to know.
 

jankj

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Lithium batteries only, otherwise one side of your neck will be much stronger than the other. (unless you rotate your flashlight every other week)

Am I overanxious if I get a bad gut reaction from seeing the words "lithium batteries" and "fire fighting" in the same application?
 

TomInOregon

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Lithium batteries aren't good in heat? I kind of like my head. I've become attached to it.

Tom
 

Federal LG

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Tom

Have you ever handled a Fenix TK20 ?

It is really, really heavy!
I love mine, but in my opinion, it is too heavy to use in a helmet mount.

It´s an awesome light, but it´s heavy... I think there are better choices for helmet mount, like Fenix LD20 or Quark 2xAA neutral.

:thumbsup:
 

TONY M

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Tom

Have you ever handled a Fenix TK20 ?

It is really, really heavy!
I love mine, but in my opinion, it is too heavy to use in a helmet mount.

It´s an awesome light, but it´s heavy... I think there are better choices for helmet mount, like Fenix LD20 or Quark 2xAA neutral.

:thumbsup:
^^^I agree that it is a HUGE 2xAA light.

The Quark 2xAA tactical weighs about 62 grams while the Fenix TK20 weighs a claimed 152g!

The Quark comes with a warm white option too.
 

jankj

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Lithium batteries aren't good in heat?

Not sure. Nip over to the battery section and search there.

Lithium disposable (1.5-1.6v) which you can use in TK20 is not the same as rechargeable li-ion (3.7v). I certainly would not use rechargeable li-ion on a firefighters helmet, at least not without doing my own research to pin down what is it really about this li-ion chemistry and heat, anyway.

Single use lithium batteries (1.5 or 1.6 volts, not quite sure) is probably a lot less volatile than li-ion. I'd still check it out before using them in a fire...


That being said, I support the notion that the TK20 is too heavy for helmet mount. The quark AA or AA^2 with neutral emitter gives you a similar beam pattern and a warmer light, so they should cut through smoke, but they are much smaller and lighter. Downside is they're more complicated to use (lots of modes and the like). Probably the tactical version of AA^2 is the thing for you.
 

offroadcmpr

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If you are used to having a heavy light on your helmet, I don't think it will be that bad. According to this site the uk 4AA that you currently use weighs 156 grams, which is actually more than the Fenix. I am not sure if that is the weight with or without batteries though. Either way it wouldn't make that much of a difference.

I say go ahead and use the Fenix, unless your old light is hurting your head or neck or something. In that case try a lighter light.

Maybe its just me, but once I put in a heavy helmet, a "heavy" light doesn't seem that heavy anymore. I used to go caving with a old petzl Zoom with the 4c batteries attached to the back of my helmet and thought nothing of it.
 

Archie Cruz

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I am planning to purchase a Fenix TK20 for firefighting use since I believe the warmer beam and smooth reflector will cut through smoke better than most LED lights. The problem I am having is finding a helmet mount that will fit. I am looking at the Blackjack helmet mount, but I'm not sure the light will fit. The specs show the TK20 with a 34.1mm diameter, but I am not sure if that is the body or the head. I am also wondering if the body under the grip is slimmer all the way to the tailcap (If I take the tailcap and grip off I can slide the body into a mount). Basically I just need the diameter of the body in different locations so I can see what size mount I need.

Thanks,
Tom

You are right about warmer beam cutting through smoke and in fact, it's best at night for MOST uses. The Firestore is a great resource. Just get the mount and try it. should work. What helmet BTW?
 

TomInOregon

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We wear Bullard FX or PX helmets. I'm really not worried about the weight. As it is I don't notice the 4AA light I have. By the time you add the weight of the helmet, Nomex hood, SCBA mask and radio adapter, the light is a very tiny amount of weight comparitively.
What really impressed me was this video showing how the warm light helps cut through particles better. I have noticed this phenomenon in person, too, but didn't have both warm and cold lights on hand to compare directly. I had also considered the Streamlight Vantage, but it costs more, isn't as bright and is a colder light.

Tom
 

Federal LG

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In this case, go for Fenix TK20.

You´ll not regret... I have one, and it´s an awesome light!
 

TomInOregon

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Just an update in case anyone else is thinking of trying this. I got the Blackjack BJ003 helmet mount and the TK20. I tried mounting the combo on my helmet and found a few problems.

First, the set screw on the Blackjack that secures the light in the mount presses on the rubber grip instead of on a metal part. I expected this, but just mentioning it for anyone else. In my opinion, this is a good feature, as it still secures the light in the mount, but it provides a shock-absorbing feature that helps protect the light. The modes can still be changed.

Second, the body of the light is a little long for mounting underneath the brim of the helmet unless you don't have a visor. I did manage to mount my Dereelight CL1H V4, but ran into the problems mentioned below. If I didn't have a visor, I believe it would have worked fine.

Third, with a visor, the Blackjack mount is unusable with pretty much any light. When mounted above the brim, the head of the light is 1/4 to 1/2 obscured by the visor mount and pivot regardless of the visor's position. The light still manages to throw a good beam, but it is dimmer. When mounted below the brim, it's good with the visor up, but with the visor down, the light shines inside the visor and pretty well kills your ability to see. The light also illuminates the brim of the helmet a little and some people may find the light distracting.

Last, the Blackjack mount has no adjustment for up/down at all. The beam from my TK20 in the Blackjack mount was ~18" up and to the left of my UK4AA at 10' distance. Being off to the left wasn't bad, but being higher meant I had to hold my head lower and roll my eyes up in order to see what was being illuminated by the hotspot in front of me. I could adjust the left/right with the Blackjack mount to some extent by installing it slightly skewed if I wanted to. It would have still been secure.

I didn't notice the additional weight at all. I mounted it to the left side of my helmet, planning to use it along with my current UK 4AA on the right side until it has proven itself. With both lights mounted, it was pretty balanced and, for the first time I didn't feel like my helmet was wanting to roll to the right. My plans now are to try again with the Helm-A-Clip mounts H1024-1 and H1024-3. I should have tried them to begin with since they allow up/down adjustment, they're cheaper and they appear very similar to the mount we currently have, so they will most likely work. I got influenced by the Blackjack's reputation, which was apparently formed mostly by firefighters who either use goggles instead of a visor or who didn't have a helmet mounted light before and are using one for the first time and don't know any better. To be fair, it is a very well made mount and your light is far less likely to get hung up on something, but it is completely unusable in my application.

I'll post again when I try them out in case any other firefighters are looking for a flashlight helmet mount. I hope this information is helping someone. I will probably end up trying the Streamlight Vantage as well, but I expect to only use it as a backup light or scene light. The whiter light will work better for these purposes.

Tom
 

TomInOregon

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Yesterday I received in the mail the Helm-A-Clip H1024-3 flashlight holder. I had also ordered the H1024-1, but it's apparently on backorder. Anyway, I put the H1024-3 on my helmet last night and I was pretty impressed overall. It doesn't feel as strong as the Blackjack mount (of course), but it feels like it will hold up to average use. This mount was only $9 versus $22 for the Blackjack, so I will probably buy another one as a spare. This mount doesn't require tools to install or adjust, but I will probably go back and tighten everything again with tools just to make sure it stays put. I have this one mounted right behind the visor mounting point on the left side of my helmet. Instead of lifting the light above the visor mounting point like the UK 4AA mount, this one holds the light off to the side so it protrudes from the side of the helmet probably 2-3 inches, so it could be a snag hazard (I have never snagged the UK 4AA light on anything yet since I am aware that it's there).
The light I am using (The Fenix TK20) has the barrel tapered down in diameter from the head and it's round, so it doesn't have any flat surfaces to secure the light in the holder. It also has a rubber grip, so it's harder for the set screw to secure the light. Nonetheless, by really tightening the set screw, it holds the light securely and allows me to change from low to high by twisting the bezel of the light without it moving. Last, I will discuss the adjustments. This is where the mount really shines. It is adjustable up and down, left and right and you can pretty much point your light wherever you want it. After mounting the light initially, I turned it on along with the UK 4AA on the other side and the Fenix was pointing way high and to the left (much like the Blackjack). I loosened the adjustment knob and I was able to quickly and easily move the beam to several inches to the left of the UK 4AA beam at 30 feet. At 30 feet I can barely even see the UK 4AA beam anymore. With the Fenix, I have a nice, tight ~6 inch diameter circle of light at 30 feet with a decent spill and that's on low. I just installed this last night and haven't used it in the field yet, but so far I like this setup very much. I may need to make a few more adjustments, but I believe this setup will work for me.

Tom
 
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