I have a UniqueFire UF-T20
Got it from Lightmalls, just under $20, as they usually are.
XM-L rather cool white, I have a tailcap current of some 1.5 A, battery not freshly charged.
3 modes: high, low (visible PWM), panic.
Very short next mode memory, so it always starts at high. 
Has a glass lens, which seems to be okay, but not a high grade lens.
I think the XM-L is too big for this setup.
I will put in a smaller LED, but thatās not what this modification is about.
Right picture: Thatās basically the essence of this modificationā¦
I took away the O-ring and the ridge that held it in place.
And so ā¦
ā¦ increased the āhead travelā by 2.5mm forward.
But without the O-ring, itās of course rattling and looseā¦
Some smooth guiding is a must.
The rim thatās left is just wide enough to make a deep groove in it.
All you need is a good lathe.
and several sharp pointy things, like mini screwdrivers, a very flat saw blade, mini files, snap-off blades, etcā¦
Deep groove, holds an O-ring really well.
Somewhere in there between those rings in shades of grey, you might see the grey O-ring, maybeā¦
I tried various O-rings, and this one was ājust rightā.
But it had a nick and it snapped, so now thereās a black one thatās ājust a wee thickā :~
Anyway, the head can move 10.5mm now, and you can see the threads appearā¦
But forward is the only way you can go.
The design prohibits to let the head zoom out / wider any closer.
First of all itās the aspheric lens that stops it, because it touches the edge / rim where i just put in the grey O-ring when zoomed out.
Secondly, the threads on which the head moves stop thereā¦
When you take out the lens in zoomed out position the head is only just (not) held there by its threads.
So, the head now goes 2 mm further from the LED.
This means the LED has to move forward 2 mm also to focus it in zoomed in positionā¦
Aluminium ring.
I cut too much offā¦ quite a gapā¦
(NOTE: ring in the picture is 2.5mm and had to be made flatter eventually.)
The picture is not fantasticā¦
but you can see itās not really possible to go much further with this.
I think i have about 2 mm between LED and lens, zoomed out.
And THAT is what this is about!
To make a wide beam, as wide as possible, the lens should be able to touch the LED.
That isnāt possible this way, but i got 2 mm closer !
Normally the head can move 9.5mm from zoom in to zoom out.
I could only add 2 mm to that, so now it can move 10.5mm.
2 mm is not much, but itās an increase of some 22% which is rather significant (i hopeā¦)
IMPORTANT!
Tricky:
The new O-ring has moved forward compared to the stock situation.
So, when the lens touches the base (fully zoomed out, wide beam) the cylinder (the head) just comes off the
O-ring guidance
This is solved by using a thinner O-ring under the lens
(replacing the big O-ring as seen in the first picture)
Now the head can move just a little less to widest beam, but itās mechanically better that way.
...and this is why this topic is not so clear about the 2mm or 2.5mm... It's a little difficult to explain sometimes, especially with zoomies, where head moved out is actually zoomed in
[EDIT]
The restricting factor is of course the ācylinderā length, the inside of the moving head, which slides over the modified rim with the grey O-ring.
That rim is made to be as narrow as possible so we can have the maximum moving distance AND an O-ring as well.
There is only just 2mm to gain hereā¦ :~
Yeah it makes a difference, the flood is wider zoomed out then before.
But thereās still about 2mm between LED dome and lens.
And itās a very bulgy aspheric lens, so every mm of distance countsā¦
[/EDIT]
Some beam shots will follow.
Then we can see what difference it actually makes. 
[EDIT again]
Uhmā¦ lazy Jerommel should take pictures!
:8)
[/EDIT again]
