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Thread: better securing of optical mounts?

  1. #1
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    Default better securing of optical mounts?

    A drop of epoxy on the set screws of lens and mirror mounts, worth it? Idea is to eliminate or reduce the screws loosening and thing misaligning.

    Simply pressing the epoxy piece with pliers will get it off later if when needed.

    Also what is the white stuff on the collimator lens mount threads I see on some builds? Thread seal tape?

  2. #2
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    Yup, Teflon tape.

    ...Mike
    Runs with Lasers

  3. #3
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    Pros use Red Glyptal varnish

    http://www.onlinecomponents.com/m.g....58f3cs50xZpc58

    http://www.alliedelec.com/gc-electro...002a/70159525/


    to stop screws in sealed instruments from turning and to retain position on optics mounts. Epoxy will strip the threads off 80 pitch screws used in optics mounts. A bit of Glyptal will harden enough to stop the drift, yet break off when you turn the screw. Glyptal has probably been used for sixty years for this...

    Steve
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  4. #4
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    I will use that. But out of curiosity how does epoxy strip threads? While breaking?
    And about the teflon tape, is it used to make a tighter fit which is less likely to loosen?

  5. #5
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    Teflon tape is only used when the "Swiss Screw" machine that makes the optics mounts, is poorly set up. Its very easy to ensure good product yields if you back off the tolerances and make a loose fitting thread, The customer may then be damned to use the cheap junk. The quick, unprofessional trick is to then stuff the resulting needless gap with tef tape.
    !
    Laser show projectors are generally not stable enough to expect to be able to permanetly lock down anything but the required "Danger Laser" sticker. Dichro mounts drift, collimated laser diodes can shift emission locations, thermal cycling loosens things up, all sorts of reasons. So most of us would never use any chemical except on a very worn out optics mount.
    !
    Most good mounts use an 80 pitch thread, and the thread to thread distance is very small, and the threads are a few hundreds of microns tall at best. Epoxy will strip them when removed.
    !
    Steve
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  6. #6
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    Quote Originally Posted by mixedgas View Post
    So most of us would never use any chemical except on a very worn out optics mount.
    Are you referring to usage of the varnish?
    Your previous post sounded like it was a good idea used for decades.

  7. #7
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    The varnish is soft if applied in a thin coat, and if you avoid saturating it, it will break free when the screw is turned into the mount

    Steve
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  8. #8
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    I'm confused, is it a good idea or not to use varnish for securing set screws?

  9. #9
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    Quote Originally Posted by syrah View Post
    I'm confused, is it a good idea or not to use varnish for securing set screws?
    YES.
    Teflon on the thread and Glyptal varnish on the head is best combination IMHO!
    Cheers

  10. #10
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    I actually found that the soft tip (nylon) set screws are best.
    For example:

    http://www.mcmaster.com/#set-screws/=13ljx6l

    The reason these work so well is that the position of the lens/mirror is actually determined by the hard surface that comprises the rest of the mounting cavity and the set screw only serves to apply pressure to maintain that contact. The conformable plastic allows you to apply this pressure progressively and the pressure this then places on the threads eliminates any play (or loosening). A hard tip set screw goes from loose to "crack" in so short a distance that you either distort the optic or risk some play.

    I replace the set screws in even high end mounts with these and they work well. Also, you don't break the adhesive loose each time you replace the optic.

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