502B to C8 converter

I think that stainless bezel ring should unscrew, but it looks hard to get a grip on without special tools. I have a couple of these style lights on order, but don’t have one to try. Im sure others here can give some advice

Pretzy’s correct, the bezel ring will unscrew, if you use [carefully] needlenose pliers to remove the ring. You could also use a bit of steel to make a dedicated spanner that fits the ring. Surefire makes such tools but they cost more than your light!


An old hacksaw blade can be snapped close to the right length and ground for precise fit. I have used that as a tool for removing slotted rings. Smooth the edges but don’t round them. It is brittle but should be more than strong enough and is quick to make. Wear safety glasses!

Hi chah
You have to unscrew the curved shoulder part ,which is a threaded tube, from the hexagonal part. The shoulder part should not have been separated from the long tube.
Hope you make it.

So just let me make sure I understand. Pretzy/Gurthang are saying I can remove the metal ring on the front side of the head (holding the glass) if I had the right tool, while sixty545 is saying I should be able to open the other side that attaches to the body.

I was thinking more along the lines of what sixty545 said. But I am unable to grip the smooth shoulder part with sufficient force and exert enough torque to separate these them.

Either way should work chah. Another tip, if you use a tool to unscrew the bezel ring, put a piece of business card or thin plastic over the lens to prevent scratching it if you slip.

I only have one P60 host, but it’s a SkyRay S-R5. The drop in access is by unscrewing the body tube as sixty545 mentions, but it is a very different design. I would think that would be the normal way, but some budget lights vary.

Thanks for all your suggestions and the information. I managed to get the shoulder removed from the head. It wasn’t using any tool, I mounted it back on the body, and using the extra grip and leverage from the body, I was able to unscrew the head piece. When I checked, the O-ring between the head and shoulder part was dry which made it harder to unscrew. I applied some O-ring grease.

It brought me back to my original problem with this 504B, which was that it changes modes on me and is much dimmer than my 502B. I found the cause of this problem. It was the tail switch. The on-resistance varied from 10ohms to 100ohms, whereas the on resistance on some of the other switches is less than 1 ohm.

I used the two probes of my multimeter as a tool to unscrew the switch (insert into the two holes in the tailcap and rotated the piece out). Measuring the on resistance of the extracted switch yielded less than 1 ohm. So it was a dirty connection between the electrical switch and the threads of the switch. I cleaned the threads using cotton swabs and isopropyl alcohol. They are quite dirty and the cotton swabs are black after finishing the job. Reassembling the switch and reconnecting to the 504B and now it works fine. After realizing the connection between the switch and the threads, and the threads and the body have an effect on the flashlight’s performance, I cleaned out a couple of my other lights too.

After that I compared the brightness of a 501B, 502B and 504B and qualitatively speaking, the 501B looks the brightest to me, and the 502B the dimmest, with the 504B quite close to the 501B. I switched the drop-ins from the 501B into the 502B, and the 501B still looks brighter. I then switched the batteries of the 501B and 502B and still, the 501B looks brighter. Maybe it’s transmissibility of the front-end glass.

I wanted to see whether the 502B was really less bright than the 501B as it appeared to my eye. I created an intensity profile of the torch at a distance of 1m for some of the flashlights that I have. I put the torch on a table and shone it at the wall at a distance of 1m. I got one of those paper tape measures that Ikea gives away for free and stuck it on the wall with beam center around the 50cm mark. I have a light meter that can measure eV and I took a reading every 5cm from 0 to 100cm for a whole bunch of lights that I have. The results are here:

It does appear that the 502B’s are dimmer than the 501B and 504B. One of the 502B’s is a T6 and the other 3 are U2’s. I had mixed them up so I couldn’t tell which was which, but from the light-meter readings, it looks like light 2 should be the T6.

For comparison, I’ve put the C8 XML-T6 on there, and what a difference. The C8 really produces a lot more light. Not only does it produce more light, but it columnates it into a tighter cone too. I ran a second set of measurements comparing the C8 T6 and the various cheaper C8 Q5’s. I also added the 3T6 which has 3 T6’s in a single head for comparison:

The C8-Q5’s put out a really small bright spot, which at its center is as bright as the T6. The 3T6 produces a nice big bright circle, but at its brightest point, the C8-Q5 is brighter! that surprised me.

Have you tried with a strap wrench?


You have just proven [as others before you] that the venerable XR-E emitter is still the best emitter for “throw”.

Any luck opening that head up and removing the reflector?

I find what works well is vice grips and a clamp. With that you can unscrew basically anything.

Hi Gurthang,
Yes, thanks for asking. I screwed the head back onto the body, then used the additional leverage (grip) that I could obtain from the body and with a bit of strain, was able to detach the shoulder from the head. The problem was that the O-ring was dry making it harder to loosen.

However I still have a problem of a crappy switch despite cleaning it out a couple of times.

I thought that the throw was more due to the reflector than the LED. But I can see that the shape/size of the LED’s glass could have a role in throw.

If I remember my high school physics, the best shape for the reflector should be a parabola and the LED should be at the focus of the parabola (ie: a point source) for the rays to come out parallel. I suppose that a small emitter would be closer to a point source than a larger emitter which could be why the XR-E might have better throw per lumen than say, the XML. But for throw, the most important is that the reflector is a big enough parabola to collect and columinate as much light as possible.

I suppose if someone had the time and motivation, they could do the mathematics to design a reflector that would columinate the light better for the larger XML.

This conversation brings me to another thought about zoom-able flashlights.

Currently zoomable flashlights use a lens to columinate the light. The light source is moved relative to the focus point of the lens to change the degree to which the lens columinates the light. The disadvantage of this method, is that when you move the lens further from the source, such as when you want to zoom in, more light hits the walls of the torch and less light hits the lens and makes it out the front. This is why those zoomable torches focus the light, but at the same time produce less lumens OTF at the zoom-in position.

If instead of using a lens that loses photons at the zoom-in position, we use the parabolic reflector in which all photons are transmitted (only the angle at which they’re transmitted is the question), then we could design a zoomable flashlight that doesn’t lose any photons at any zoom-position.

The way to zoom in this case is to move the LED forward or backwards slightly. At the focus point of the parabola, you will get maximum columination, and maximum throw. If the LED is moved forward a mm or two, it will no longer be at the focus of the parabola and thus the rays will come out non-parallel and give a wider circle of view. Another advantage is that you won’t get the image of your LED when the LED is at the focus of the parabola like you do with the lens.

All that needs to be implemented is a mechanism to move the LED forward and backwards by a few mm.

Any flash-light manufacturers reading this want to give it a shot? :slight_smile:


I know that this is an old thread, but I had a question. Even if there was a P60-to-C8 convertor/adapter, what about the P60 reflector? Don’t the P60 drop-ins all have an integral reflector? Would you have to remove the reflector from the P60 drop-in, and then use the reflector from the C8-style host?