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Thread: Anamorphic Prisms - a quick heads up...

  1. #1
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,242

    Default Anamorphic Prisms - a quick heads up...

    This may be preaching to the converted, but if you are planning on using anamorphic prisms and clamps to hold them in place, be VERY careful with how you tighten them.

    I was putting mine in place last night using Dave's dual 445 module kit, and I lightly finger tightened the top clamp plates in place. In the process I managed to put a small crack in the front prism.

    I think it happened because the clamp was wound down slightly uneven and lower on the thin side of the prism, so this took all the force. However, I used very little pressure, so it clearly does not take much to break these.

    Hopefully it is in a position that won't affect the beam path (top outer corner) but it was all too easily done!

    Let my misfortune be a lesson to other...

  2. #2
    Join Date
    Jun 2010
    Location
    Australia
    Posts
    3,730

    Default

    I learned this lesson too, although I was more lucky only chipping a corner that does not matter.

    I now use a small adhesive rubber foot on the top bridge to place pressure on the prism.

    Click image for larger version. 

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    I think this might be a common mistake, but people are less likely to advertise the mistake!
    This space for rent.

  3. #3
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,242

    Default

    Glad to hear its not just me who has fallen foul of this!

    I think I might add some sort of soft facing to the underside of the top clamp, but then it may make it difficult to move when doing the fine adjustments.

  4. #4
    Join Date
    Jan 2008
    Posts
    3

    Default

    Quote Originally Posted by norty303 View Post
    anamorphic prisms
    Have they bevels? smth like these ones
    Click image for larger version. 

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  5. #5
    Join Date
    Feb 2005
    Location
    Switzerland
    Posts
    1,392

    Default

    A little advice would be to put a bit of thermal grease between base plate and prisms, so they are holding enough in place by themselves and they "slide" better for the adjustments. Don't know if it helps when tightening them though

    You can see the grease on my modules here

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