# Build Log: PentagonLight X3



## PCC (Dec 21, 2010)

I purchased this PentagonLight X3 used on the Marketplace with the intention of modifying it. It was sold as a non-working flashlight because the bulb had burnt out and the proprietary bulbs for these lights are no longer available, since PentagonLight is no longer in business. This thread was put together with the intent of showing what I have done with my light as well as sharing ideas from other PentagonLight X3 owners about what they can do with their flashlight to revive it and put it back to use. My example was not a pristine shelf queen and shows a few knicks here and there, but is in otherwise great condition.











*Introduction to the PentagonLight X3*

The PentagonLight X3 is a tactical style 3 X CR123a incandescent flashlight finished in a slightly green HA III coating. It's a modular flashlight as the head unscrews from the body and at least one replacement LED head was available from PentagonLight at some point. This LED head is of a showerhead configuration and I've only seen pictures of it so far. The end of the body tube has a threaded on plastic and brass stopper to prevent the batteries from falling out if you change the head in the field. It's a very nice design that I'm hoping to take advantage of, as you will soon see. There are double O-ring seals at all major body interfaces: at the bezel, between the body and the head, and at the tail cap. I should note that the threads at the head of the flashlight body are different from the threads for the tail cap so you cannot thread the tail cap onto the head end and vice-versa. I purchased a pair of protected AW 17500 batteries for this light and it’s a tight fit with the labels on them. Even with the labels removed they don’t just fall out.















The tail cap is thread compatible with SureFire 6P tailcaps and every tail cap that I tried that will fit my 6P fits and functions fine on this light. The tail cap is a LOTC momentary twisty, much like a SureFire Z41 in use but much more complicated in design and manufacture. On my sample there appeared to be a problem as the momentary function did not work well: you had to twist the tail cap down so far to get the momentary to work that a further 1/8 turn would turn it on. Twisting it out a hair from this position would lock it out. I took the tail cap apart and found that the spring that returns the main button was getting in between the button itself and its retainer. I put that part into the lathe and cut off the shoulder that was crushing the spring and the problem was solved. I don't know if this flashlight came like this originally or if the previous owner had done something to it to make it this way. A picture of the tail cap and its guts spread out will be shown later.



*Things that I don't like about this light*

The light uses a proprietary lamp assembly that incorporates the reflector in its design. This reflector has a diameter of about 35mm. This lamp assembly is no longer available and the 35mm size makes it difficult to find a compatible incandescent or LED lamp assembly from a different company or the aftermarket to work with this light. This pretty much makes this flashlight a dinosaur unless you are willing to modify it.



The tail cap is much too complicated in design, probably to skirt SureFire's patents, and is fairly heavy because of the solid piece of steel that they use for the button and its retaining ring. The button sits under an over-sized rubber cover so finding replacement button covers will be difficult if you tear yours or wear it out. The button cover is 20mm in diameter and the 19mm diameter Solarforce button cover I tried won't quite fit right.










*Summary*

It's a very nice flashlight with a few shortcomings. Both shortcomings can be overcome with some creativity and a lathe. All-in-all, I'm very happy with this little light and am looking forward to doing some mods on it.


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## PCC (Mar 10, 2011)

Written by *PCC* on 12-21-2010 10:42 AM GMT

The first thing I did to this light was to make it work again, as a flashlight. To do this I converted it to LED using some spare parts I had laying around.






I had a Ledil Eva flood optic as well as a light engine from a Solarforce Masterpiece Pro 1 head so I put them together and they both fit inside of the stock X3 head, after I cut the outside diameter of the optic down to fit. The result is a nice floody light of over 200 lumens but there's no thermal path so it is only used for short periods, for now.

The second thing I did to this light was to change out the momentary LOTC for a forward clicky. To accomplish that I made an adapter ring to fit a McClicky plus brass kit, as sold by Oveready, into the X3 tailcap in a recessed fashion. I tried to use the original button cover, but, the overall length of the tail cap is too long and I either could not get a good button feel (push the button in 3/16" before it goes momentary and over 5/16" to latch it on) or I would not get contact if I got the button to work. The compromise is the recessed button. As you can see in the picture, there is a small O-ring at the top of the ring that ensures that this is still water resistant.


















*Further observations*

The original lamp assembly from the X3 can be taken apart with some coercing and the threads on the reflector just happens to be the same as what is used on most aftermarket P60 pills, at least the ones that I have tried from ThruNite and Dereelight. Unfortunately, the LED sits too low in the reflector and I could not get it to focus.











I have obtained a LumensFactory EO-E2R (150 lumens) lamp assembly and I will see about making an adapter to make this work with the stock reflector from the X3. I have tried it just placed into the back of the reflector with power applied to it and it seems to work so it is promising. I've also tried a stock SureFire E2e lamp but the weird shape of the back of it will make adapting it to this reflector difficult. Stay tuned.

Here's a teaser picture of possible mods I want to do to this light:






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Written by *PCC* on 12-24-2010 11:58 PM GMT


^Gurthang said:


> PCC,Interesting project. Good idea using the LF incan bulb. I wonder if a D36 LF or NailBender drop-in would fit the X3? I'll be watching for your next installment.


No, I don't think the D36 will work in the X3. I have not tried it, though the X3 reflector fits inside my Z46 bezel with plenty of clearance all around it.



bigchelis said:


> I vote for you to put a McR38 reflector in this thing and then use a XP-G R5 and you will have a Malkoff Houndog replica with nice beam and 20k lux potential.These Pentagon hosts are really nice and have probably one of the best grips and wish they were still around.


The McR38 reflector would have to be cut down to fit inside the X3 head.
Yes, I like the knurling and he overall feel of this light in my hand. 

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Written by *PCC* on 01-15-2011 12:16 PM GMT
Okay, an update. I made an adapter ring for the stock reflector to use the Lumens Factory EO-E2R bulb in this light:







The stack height of this adapted bulb and the springs are taller than the original bulb, but, it all fits in the X3. The original bulb outer spring needs to be used, here, because the inside diameter of the end of the body tube is smaller in diameter than a P60 drop-in spring and this will cause contact issues. The threaded collar allows me to adjust the height of the bulb relative to the focal point of the reflector to adjust the focus. The ideal focus with this bulb is with the adapter about one millimeter above the rim of the reflector.

I guess no one out there has a Pentagonlight X3 anymore? 

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> Written by *flex76italy* on 01-17-2011 12:21 PM GMT
> 
> 
> PCC said:
> ...


 
Written by *PCC* on 01-17-2011 01:56 PM GMT
Sounds like a nice light. Please share your results when you have it done. 



> Written by *flex76italy* on 01-18-2011 02:14 PM GMT
> Sure! Sure! :thumbsup:


 


> Written by *dudemar* on 01-29-2011 11:02 PM GMT
> Just stumbled upon this thread when I looked up Pentagonlight in the search engine. Awesome project you have going, and I'm glad to see you've come up with a way to change the rubber switch cover.
> 
> 
> ...


 
Written by *PCC* on 01-30-2011 08:17 AM GMT
Nice! I've never seen a PX1 before. From the pictures that I've seen that light is a polymer version of an X1, right? I wonder if it has an aluminum head or a polymer one? If it's polymer then I would keep it incan.

I picked up a NOS X2 from that popular online auction website. It's a nice light, though it doesn't seem to be as nicely made as my X3 for some reason. It has a clicky tailcap and a glass lens. Other than that, and the smaller dimensions of the body tube and head, it is very similar to the X3. The head on the X2 is removeable like the X3 and can be swapped between the two with no problems other than the voltage differences between running two or three CR123a cells. I don't particularly care for the feel of the stock clicky on this light as the button is very stiff and lacks any tactile feel to it. The clicky is almost completely silent when it latches on and the stiffness of the button means that sometimes you won't get it to latch on when you thought you pressed it far enough to do so. I'll be swapping this for a McClicky much like I did on my X3, but, I cannot remove one of the contact rings inside of the tailcap when I tried taking it apart. This ring lacks any dimples or anything to attach a tool to so removing it will involve a drill. The incandescent lamp assembly looks like it, too, can be taken apart much like the X3 LA, so, with the same mod this light can be revived using Lumens Factory bulbs. The diameter of the reflector is a bit more than 27mm, but less than 27.5mm. I tried fitting a McR27 reflector, which has a 27.5mm diameter, and it does not fit. A quick pass on the lathe should take care of that. Any LED lamp assembly that will fit a SureFire 6P should fit this light so long as you use a negative spring, but, I would caution you to use a lower power one or limit its use to short bursts as there is no thermal path at all using one of these unless you wrap the drop-in with aluminum/copper foil sufficiently to reach the walls of the head. I'm thinking of finding someone with a larger lathe or getting a boring bar for my small lathe to allow me to bore both of these lights for 18mm diameter batteries. As it is now, my 17500s slide into both flashlight bodies but are a bit tight and in both cases the batteries don't just fall out in your hand. 



> Written by *akajimmy* on 02-05-2011 08:16 PM GMT
> When I was perusing on AR15.com. Someone over there mentioned that the elzetta tailcaps fit on SOME of the pentagon lights. The tailcap on my elzetta did fit on myX3.


 
Written by *PCC* on 02-06-2011 10:31 AM GMT
As far as I can tell any tail cap that will fit a SureFire 6P should work on the PentagonLights.

I just saw a black X3. I didn't even know that black versions existed! I'm now on the lookout for black versions of the X1, X2, and X3.


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## akajimmy (Apr 8, 2011)

Any new updates on this. I really like the adapter mod you did for me.


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## PCC (Apr 8, 2011)

I'm glad you like it.

I haven't had any time to do anything with this light. Well, almost. I was given a 32mm OP reflector from a D-Mini flashlight. It was a spare so it wasn't really needed. It fits the X3 fairly well. I then took a ThruNite 1.5A XM-L three-mode pill, put a negative spring on it, then assembled it using that reflector. It works, though the thermal path is almost non-existant. I'm going to make an aluminum adapter for the ThruNite pill to center it and to give it a thermal path. That's the short-term plan for this. Oh, yeah, I swapped the guts from my X2 tail cap with the X3 because I wanted the softer clicky on the X3 and I've got the McClicky in the X2. I want that light to have a lock-out feature, but, the inside of the tail cap and the end of the body tube are not anodized so I'll have to isolate the McClicky in such a way that it can be completely isolated if I unscrew it a bit. I'm going to have time next month to work on this light as well as the X2 and a PM6 that I recently picked up.


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## richpalm (Apr 8, 2011)

IOW, forget it without a machine shop? I think I'd dump all the components of that tailcap and just put a new clickie in-KIS.


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## PCC (Apr 9, 2011)

Well, the original switch in the X3 is a twisty/momentary much like a stock Z41. Unlike the Z41, though, the inside of the tail cap shell is bare aluminum, so, no LOTC feature using the McClicky + Brass kit.


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## akajimmy (Apr 25, 2011)

I bought the Elzetta tailcap. It works beautiful on the X3. Now, not only do I have a Forward clicky. I have a high/low option. Twisted tight=high. Slight twist to the left=low. Now to get one of the Malkof M91 or M61HCRI dropins. I am good as gold!:thumbsup:


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