Ghetto focus ring for O-like housing/lens

[anselm]

Hello dear community,
so I am building my first 445nm and I ordered me one of those diode housings
plus a 3-piece coated glass lens that O-like sells. I'm sure many of you are
familiar with these.

Then you might also know that the lens just by itself is not easily adjustable.
It's more like "find a good spot and leave it there".
But I'm too stubborn, I would like to be able to change the focus easily.

I don't have a lathe, but I do have my car's toolbox.

So I grabbed a common M8 nut, a sliding pole (wtf?) from an optical drive sled,
and started grinding, cutting, reaming and drilling, (casualty here: drill bit broke off tip )

and then some soldering later,

well it ain't winning any beauty contest, but it fits alright:

I'm gonna slim it down a little, reducing profile, but I'm not doing
that without a power tool, so gotta wait a day or two.

Question for y'all though:
How should I best go about fixating this contraption to the lens? :thinking:
My first thought was cyanoacrylate, but I remembered reading something
about nasty fumes buggering the lens/coating...

I guess I could add a little solder blob on the inside of the ring so it will
hold in place when pressfit... But that wouldn't be so elegant IMHO.
And I don't wanna endanger the lens with unnecessary and large forces.

Any ideas?
Thanks

 

[Bionic-Badger]

You can try some silicon glue. Teflon tape works too; though it's not "permanent" it does stay in place very well.

 

[nikokapo]

You can also try using one of those hooks that screw to the wall and bend it so that it grips on the focusing ring.

 

[anselm]

Thanks for your suggestions.
As for now, after grinding away material on both sides to make the thing slimmer,
it seems to hold quite nicely after gently pressing it into place, by hand.

It doesn't fall off during normal usage, so until it does, I'll keep it this way.

It works quite nice too, you can pull the focus like a camera-man.
Lemme see if I can make a video if you're interested.

I guess it would be kind of cumbersome for a pointer, but I think this blue monster of +1W better belongs in some kind of "box". Let's call it a portable labby.

 

[BShanahan14rulz]

If you have extremely good vision and very very steady hands (or am I the only one with trouble with these things?), you can unscrew the inner lens retaining ring and dump the 3 lenses and spacer out. Then you wouldn't have to worry as much about damaging the lenses from soldering or glue outgassing. Downside is that two of the lenses are kinda similar and hard to tell apart, and while the diagram on the forums here is clear enough, it was hard for me to differentiate between the two thinner lenses.

Background on my particular lens is that it was part of a focusable blu-ray pen I purchased from O-like. Was curious, so took it apart. Looks just like a half-threaded aixiz glass lens. The bumpy thumb-ring thingy was press-fitted onto the smooth part of the barrel, and went down to the o-ring.

here's info on aixiz glass lens disassembled:
http://laserpointerforums.com/f49/aixiz-glass-lens-disassembled-40222.html