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Scoop
Joined: 01 Oct 2001 Posts: 11
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Posted: Thu Oct 18, 2001 10:11 pm Post subject: |
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The Kalart Rangfinder on my 4x5 Crown was in need of some refurbishment. The moving image was so dim it could scarcely be seen, even in sunlight.
The problem was that the silver coating on the beamsplitter window had deteriorated to the point that there was little reflection. I decided to try the repair described by Ed Romney (on the this site). I'm pleased to report that it really was a simple job, taking about 30 minutes and the rangefinder is bright now and easy to use.
I obtained the 50% transmission mirror from Edmund. My Kalart required a half-silvered mirror 1/2" x 5/8". This I cut, as Romney describes, by scoring the reverse (non-silvered) side with a tungsten carbide scriber (got mine at Sears). I'm guessing that one could cut a mirror about one-half this size, if needed, without too much trouble.
The old mirror was held in its retaining slot with a dab of cement at each end (along the 5/8 dimension). I snapped the old mirror off with a pair of pliers (wear eye protection here), chipped away the old cement, and carefully cleared the remaining glass out of the slot with a narrow bladed screwdriver. Sounds more formidable that it actually proved to be.
The existing miror in the Kalart was 0.060" thick,and the slot which held it that dimension. The mirror from Edmund was 0.030". I wound up making a couple of spacers to hold the mirror firmly against the front edge of the slot by compressing some carboard with a rolling pin to ca. 0.025, putting a small piece at each end of the mirror, the allowing the carboard to swell tight with the Duco cement which I used to hold the new mirror in place.
I'm keeping the remainder of the 3x3" beamsplitter in case I have to repeat this repair in another 54 years. |
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Les
Joined: 09 May 2001 Posts: 2682 Location: Detroit, MI
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Posted: Fri Oct 19, 2001 12:42 am Post subject: |
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Well done scoop!
_________________ "In order to invent, you need a good imagination and a lot of junk" Thomas Edison |
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steverose108
Joined: 13 Sep 2001 Posts: 6 Location: San Diego, CA
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Posted: Fri Oct 19, 2001 6:46 am Post subject: |
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Good job! I did a Kalart on my 23 Crown too, with Edmund glass which I cut with an oil-feed glass cutter which you can get at a stained glass supply house. It's an old one but very accurate and made in Japan. Don't know if any advantage over scriber, but it did cut well. I wrapped the glass in paper (once scribed) and snapped it off between the jaws of a bench vise for solidity...what an AMAZING difference in the viewfinder, well worth the trouble! S |
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jdman
Joined: 13 May 2001 Posts: 302 Location: Midwest
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Posted: Fri Dec 14, 2001 6:39 pm Post subject: |
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I have a Kalart that has lost the silver on the top mirror. Is that a front silvered mirror or what. Any suggestions?Russ |
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jdman
Joined: 13 May 2001 Posts: 302 Location: Midwest
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Posted: Tue Jan 01, 2002 8:25 pm Post subject: |
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I just finished replacing the the beam splitter in my Kalart. Getting the glass was easy, cutting the glass was easy, but putting that thing in was a real pain. Anyway the operation was a success and I now have enough spares to fix a lot of cameras. Thanks to all of you. Russ |
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