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Archives of an email list on the history of binoculars. - page 77 / 150

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>Does anyone know a "cyclop" type binocular made by Hamica.? Large single objective tube and two oculars.

  I have one of these strange binocular viewing monoculars in my collection.  Mine is Labeled "Hamica Power Zoom Scope", "2½ ~ 8X 35", "Field 3° 35' at 8X".  There is also an auxilary lens marked "4~12X Attachment".  The zoom is motor driven and powered by 4 AA batteries.  Makers codes are JB-2 (Katsuma Kogaku Kikai Co., Ltd.)  and JE-46.  I have seen this same glass for sale a number of times but do not recall if they were marked Hamica.  A similar scope is listed in the 1964-65 "Guidebook of Japanese Optical and Presision Instruments" and offered for sale by Meiji Seiko Co. Ltd.  It is listed as a 2.5~8.8x40.

Regards, Jack

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Subject: 10 x 80 repair

From: gordiray@___t

> >>How do I open up a 10x80 "Flakfernrohr

> Without such proprietary tools as grip wrenches, spanner wrenches, and a

> healthy dose of experience, we would not advise opening a flak glass on

> your own. Among other things, the gearing system that times the placement

> of the different filter assemblies is exceedingly difficult to reassemble,

  Why not discard the filters and their mechanism, then plug the holes with bonded aluminum plates on the inside? Fill the resulting depressions with Devcon F or similar aluminum-epoxy mix.   Now much lighter, and the absence of the clear dummy filter does not seem to affect the aberration balance , even for an f/3.5 cone.  I have gone further, eliminating the steel IPD change dovetail and its gear and the change knob.  Delrin or aluminum stub dovetails hold the moving prism housing.  PD change  is via setscrews a la gibs on machine tool dovetails.  Delrin  rings form new eyecups, and aluminum replaces the steel reticle illuminator .   Aluminum rings , which can be unthreaded, if you will, and held by setscrews, reinforce and lighten the achilles heel of this design, namely the very thin wall of the objective housing tubes.  Now one has a comfortable handheld, with 45 inclination.    I made dozens of aluminum headrest supports on which to mount the superior copies of the 25 x 100  cushion  for which I made a mold.

  Of course, the purist non user will recoil.  I have a set of the Busch plans, from a LeitzWW II archive.  The snippets of this you see are from miscellaneous mailings by me in the past 35 years .   Now, we just need a low-risk cold coating for the optics, and all that will be lacking is correction of the sustantial field curvature.  

--Gordon Rayner

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Subject: Screw thread  substitutions,  making collimator targets, setting diopter rings

From: gordiray@___t

  The September-October 2003  issue of Home Shop Machinist has a detailed article on metric-English screw substitutions, in both directions.  I have put lots of l0-32 stainless socket caps in M5 holes, for Fuji 25 x 150 headrest support holding.  That is two screw out of a six hole pattern, and corrosion resistance was more important than  very high torqueing.  M5 socket stainless for the application were/are hard to find and the 10-32 in M5 hole is a very good approximation for many turns.  The inverse would not fit.  A local "factory authorized Fujinon repair " put some 4-40 flatheads in M3 holes.  The threads do not hold.  I have had to clean out a lot of silicone-RTV  mixed with grease around the objectives mounts over the years before adjusting. This mis-use of RTV is not factory practice .  RTV  is inferior to urethanes and the Simson  Elf-Acquitane formulations, or the non-curing, mildly stinky polysulfide Presstite "green wax", duck sh..", or 3M  Weatherban

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