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My lens is stuck. Please help!

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Hi LPF,

So, like a total noob, I screwed a G2 lens into my fancy new NUBM44 the wrong way around. Now it is stuck. I can unscrew it about a quarter turn before I feel the spring catch on something and stop turning further. I tried giving it a decent twist with a pair of pliers, but that didn't work, and I didn't want to apply too much torque to the thing. Is there any way to fix my mistake, or am I stuck with a totally unfocused diode now?

Luckily I got a few beam shots with the original 3-element lens before this happened, which I'll post in another thread.

Thanks in advance!
 

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BowtieGuy

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I wonder if the spring is getting caught in the cut grooves in the lens housing?
It should come out, but you may damage your lens housing threads and possibly twist up the spring a bit.
Try grabbing the housing with some leather or rubber between it and your pliers.

Edit: Hopefully there isn't a bugger in the threads that has already damaged them, if so, removing will be difficult, and probably damage both the lens threads and the copper diode module.
The part about only moving 1/4 turn isn't encouraging.
 
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dden4012

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The spring is catching the lens retaining ring in the lens barrel. All you can do is keep in screwing it. It should come out. You might hear a few clicks from the spring end releasing its bind as you turn.
 

GSS

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I think just what Bowtie said with the groove in the lens housing.
What ever you do I hope you have stopped and thought this out a bit before trying anything.
Just a thought, can you turn screw the lens back in a bit more very carefully and hopefully the spring will dislodge from the lens groove and then try back?:thinking:
 
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Thanks for the suggestions guys! I have tried turning the lens back and forth a bit, but I think because it is compressed so much, it is going to take quite a bit of force to dislodge. Seems like I may just have to reef on it some more to get it out, and cross my fingers that I don't damage the diode itself.

I was also thinking about heating up the assembly by either running it for a while or with a heat gun to try to expand the copper module a bit. I guess I'll figure it out after I get back from work tonight. Nothing quite like learning lessons the hard way! :rolleyes:
 

Antharak

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I was able to replicate what your dealing with, the spring is catching on the notch of the G2 barrel. just put some leather around the G2 and unscrew it. It's the only way. Make sure to blow out the module as there will be bits of spring and lens barrel. Always remember a G2 goes in lens first.
Hope this helps
Ed
 

Radim

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Thanks for the suggestions guys! I have tried turning the lens back and forth a bit, but I think because it is compressed so much, it is going to take quite a bit of force to dislodge. Seems like I may just have to reef on it some more to get it out, and cross my fingers that I don't damage the diode itself.

I was also thinking about heating up the assembly by either running it for a while or with a heat gun to try to expand the copper module a bit. I guess I'll figure it out after I get back from work tonight. Nothing quite like learning lessons the hard way! :rolleyes:
If nothing mentioned works and you go for temperature change, I would try cooling it instead of heating it with the gun or by keeping it running longer. Too much heat might damage the diode. Just make sure you leave it warm up back to room temperature slowly to prevent dew (like puting it into some case). You might add a silicagel or rice (not boiled yet) to get potential humidity reduced.
 
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RedCowboy

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I would work it back and forth as you said you have, then put enough torque on it to get it apart, you may unscrew your lens or twist up the spring but I don't see how it's grabbing the diode all that tight, personally I would twist the **** out of it, but put several layers of heat shrink over your lens barrel threads to hopefully protect them.
 
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10fenny

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Sounds like you might have something in the threads.. working it back and forth may help... but after a certain point it may need to be forced apart like rcb said. It's not like you can add some deep creep or pb laster in there. Sometimes with cars... or lasers.. you just gotta unthread the cross threaded beast and deal later. I wish you the best
 

BobMc

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This does happen once in awhile. Like it has been said, your going to have to use force to unscrew. Hopefully it's just the spring biding and nothing else. Best wishes, keeping fingers crossed.
 

Alaskan

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I wonder what the coefficient of expansion is for the materials used and whether heating or cooling might help.
 

BowtieGuy

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alphabirth, when you get that badboy apart, be sure and let us know what the problem was, and how you ended up fixing it. :)
 

GSS

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alphabirth, when you get that badboy apart, be sure and let us know what the problem was, and how you ended up fixing it. :)
Kudos Bowtie, for asking on how we can also learn:)
The heating up part scares me and any oil also. Like RedC said I can't see the diode in to much danger as its 9mm and the window is smaller in comparison.
Worst case like 10fenny said, it might take some force but you can always re work the threading if damaged.
Looking forward to see if any results yet??
 

Alaskan

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If I were to try to see if either chilling or heating would help, I sure wouldn't use much heat, just warming but the problem appears to be mechanical anyway, not just tight tolerances. I don't understand how a dog could even have screwed the lens in there to begin with.
 




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