How to focus

EDIT: Oops, I left the placeholder title in when I posted.

About a year ago I got a nice 532nm 100mW handheld from O-like. I was really happy with my purchase, the beam is nicely visible, and it can even light matches from up close. Lately, however, the beam has diverged from its original sharp point and doesn't seem to focus properly. The laser is focusable, but it uses a screw-on end cap that gets uncomfortably loose when I change the focus.





(Sorry for the blurry smartphone pics, it's all I've got)
You can see the end cap here, it unscrews and can be pulled off. Inside the cap there is a threaded lens module, which I assume can be threaded in/out to fine-tune the laser's focus.





The lens module appears to be hot glued (or something) on the threads to prevent it from turning. I want to fix the beam on my laser, so I figured I could just remove the glue, thread the lens in and out until I got a decent focus, then re-glue the lens module to hold it in place.

Is this a bad idea? Is there a chance I'll mess up my laser or the lens if I fiddle with it like this?

link2thepast said:

Is this a bad idea? Is there a chance I'll mess up my laser or the lens if I fiddle with it like this?

Click to expand...

What does the dot look like just now?

That may be the only way to do it.

The dot is about 0.25" in diameter from a couple of feet away, and about 1.5" in diameter from around 10 feet away. The dot used to maintain a nice point, but now it diverges quite a bit with distance.

Possible dirty lens? If the lens is glued into the focus lens then maybe the module slipped into the host a bit.

10fenny said:

Possible dirty lens? If the lens is glued into the focus lens then maybe the module slipped into the host a bit.

Click to expand...

A picture of the dot would help us identify the problem with some certainty.

Alright, I decided to just try removing the glue and adjust the lens. The lens module was indeed hot-glued into place, so I just used a pair of pliers to free it. When I removed the glue, the module immediately fell free--this makes me think the module had been working itself loose for some time, slowly changing the focus and diverging the beam. I threaded it back into place and everything is fine: the dot is small again and the beam is tightly focused.

Thanks for your input, I'm very happy my laser is fixed.