BLF GT (preliminary) modding thread

I know most of this thread is geared more towards drivers and LEDs, but for a filthy casual type like myself… I’m going to ask the obvious - has anyone made an adapter to put a BLF Q8 on the ass end of the GT? The diameter and thread pitch are obviously different, and there’s no real need for it other than having a long range focused light on one end and a monster floodlight on the other. Forgive me if this is totally ridiculous, my GT showed up yesterday and when taking pictures next to my Q8 for comparison the idea punched me in the back of the head. Or maybe it’s the pain meds from a recent surgery to reattach a muscle, not sure.

That’s what happens when you put a larger reflector in a flashlight.

I tried adding spacers under the centering disc. All it did was a donut hole in the beam, without making it bigger or more focused.

It still seems to me the GT hotspot is not as focused as it could be. There is simply too much light wasted around the hotspot. Or at least I think so. Can it be changed or not?

Has anyone tried a thinner centering piece?

The hotspot of my GT looks pretty focussed but when over 10 meter it is slightly darker in the middle. I’m not sure if that is the nature of the XHp35 Hi led or that the focus is less than perfect, in which case the centerpiece should be a bit thinner. I dare not sanding it down yet in case it makes things worse instead of better.

Btw, on the list of parts that would be welcomed to be sold separately should be the centerpiece IMO.

And apart from being slightly darker in the centre there is a lot of light around the hotspot that could be used in the middle. If it is even possible.

To be precise, I made 3 shims with a total height of 0,5mm and tried adding them under the black centering disc one by one, but the donut hole was bigger with every added shim.

Someone should make thinner centerpieces, I don’t have guts to sand down mine.


Here is a great thread on how to easily check your light for focus:

I remember DB Custom thinned his center piece a bit by sanding. He posted about it, with pictures; back somewhere in all the massive & many GT threads & posts. If I can find it, I’ll post a link.

IIRC, he said in his case it helped tweak the focus a bit tighter.

DB Custom can work miracles in comparison with me, I already got the idea of sanding the centerpiece down, but it is beyond my skills to do it properly. My centerpiece would be thinner on one end and thicker on the other, apart from many other blemishes I would cause, and that would not help the focusing at all.

Hi. Is your palight boss have a ring around the hotspot?

All you have to do is put a piece of very fine grit sandpaper on a flat surface, place the black centering block on it, & rub until you remove a bit from the bottom of the block.

It should be/is very easy to do that in an even fashion. As far as causing any other blemishes, I cannot understand how that would be possible using this method.

I did it with one of mine & it was simple as well as straight forward. Seemed to tighten the hotspot a bit also.

@ johny723

Here are some links where people sanded their Centering Ring. JasonWW states he tightened his hotspot considerably.

Do some reading on either side of these linked posts & there is a bunch more info.

I cannot find the photo’s I mentioned by DB Custom, but I did find several by KawiBoy1428.


Thanks, I will read through the links.

Your welcome, my pleasure. :+1:

To make clear what I mean I took a photo of both the GT and my Boss. The first photo is the GT. It clearly is brighter, but there is a lot of light around the hotspot. IF it was possible to concentrate that light, it would improve the beam.

This is a beamshot of my Palight Boss with a dedomed XP-L V6 1A. There is very little light around the center. If only I could make my GT throw the same.

@ johny723 ……. OK…… I think I now understand what you are saying. I do not think this is possible with the GT reflector / LED setup. It was designed to spill this amount of light so as to be a more “”useful”” light. :frowning:
This is what I remember anyway.

Thanks… i bet dedome xpl will give some green tint…

I measured my friend’s GT too only swapping the head and his got even worse numbers than mine. The batteries were fully charged and his GT only pushed uot 894 Kcd. Mine does 980 Kcd again but interesting the different results at different distances.

10m: 980 Kcd
15m: 969 Kcd
20m: 928 Kcd
25m: 929 Kcd

10m: 894 Kcd
15m: 857 Kcd
20m: 856 Kcd
25m: 877 Kcd

I think it is mostly a focusing problem so I will try to open the head and try enderman’s focusing method

Let us know what the results are.

We both got our GT in early March and they travelled together according to changes in tracking had only few minutes differences between the two lights. So I think they are same manufacturing batch got not so throwy. I need to get a strap wrench or something and then try focusing.

I managed to open my GT head with a leather belt :slight_smile:
I printed out Enderman’s focus checking circles with the 3 square. I have still my friend’s GT too so I checked both. Mine was good for about 1m distance and then started to seem over focused. The 3 square moved to the center. At 7-8m the 3 squares almost completely overlapping each other. That is why I got the biggest numbers at 10m because it was focused around that distence. My friend’s GT was even worse. As we seen in the intensity numbers too. So I need to sand the centering plate thinner. I needed to go to work so tomorrow I will measure centering plate thickness and sand it down a little.