Posted 05 November 2011 - 07:50 PM
So I finally screwed up enough courage to disassemble and clean internal optics on three sets of older binoculars.
Two 7x50 Bushnell Banner binoculars, circa 1960's, and one Scope Custom 7x50, circa 1970's. All were a Japanese build and the disassembly and internal construction were similar.
All I needed for tools were a small Philips screwdriver, and one tiny flat blade screwdriver (to unscrew a tiny setscrew securing a flat disk holding the eyepieces in place).
Once the flat disk was unscrewed, the eyepiece assemblies slide out, then the remaining eyepiece tubes unscrewed, leaving the prism plates. Once the prism plate was removed, the prism assembly was held in place by three screws. Gingerly tilting and removing one prism assembly at a time, I then unscrewed the lower prism strap, removed the metal prism backing, allowing me to clean the prism glass. I used Windex and Bounty paper towels to clean the prisms.
What I did not do was try to clean the inner eyepiece glass, since past experience taught me to leave well enough alone - there always seems to be a layer of grease on the metal of the inner eyepiece. Trying to clean the inner eyepiece glass brought grease onto the glass, and caused streaking on the glass on the first binocular I disassembled last year (a Bell&Howell 8x40).
I also refrained from trying to clean the inner glass of the objectives when the prism assembly was removed.
I found cleaning the prisms did the trick removing the internal "cloudiness" seen when looking backwards through the objective end. The Bushnell Banner binocular glass now looks bright and clean, viewing is noticeably brighter.
The Scope Custom binocular before cleaning had noticeable fungus "tendrils" growing on the prism glass. After cleaning there is no evidence of any fungus, or etching damage caused by the fungus.
So I was hesitant about disassembling prism assemblies, fearing I would throw the optics out of alignment, but I found the task of reseating and reassembling prisms to be easier than expected.
Cleaning these older binoculars was rewarding, I've given them a new lease on life, and made these quality build binoculars more functional.
Posted 05 November 2011 - 09:00 PM
Posted 05 November 2011 - 09:09 PM
If you can put pictures (if any taken) and steps in your website and here; that will assist other users who dare to un-assemble their binocular to clean.
Putting in your website (ifyou have one) gives quick access then here will be an excellent idea.
Posted 06 November 2011 - 11:21 AM
Posted 06 November 2011 - 03:09 PM
First photo, tiny setscrew is at 11:00am position on center flat washer.
Posted 06 November 2011 - 03:14 PM
Posted 06 November 2011 - 03:17 PM
Posted 06 November 2011 - 03:19 PM
Posted 06 November 2011 - 03:21 PM
There are two screws holding the prism in place via the prism metal strap, these two screws can be removed which permits removal of the prism for complete cleaning. In each of the three binoculars I opened (two Bushnell Banner, one Scope Custom), one of the two strap screws was not torqued completely down, but just enough to apply sufficient pressure to hold the prism in place, the other strap screw was torqued down all the way.
Posted 06 November 2011 - 04:12 PM
Posted 06 November 2011 - 04:48 PM
Not to be " picky " but only to genuinely assist in the matter of CLARIFYING instructions , which if to be provided via text only , simply MUST be unambiguous !
To that end , and again , not to try to haul anyone over the coal , would ALL please note the difference between the 'ol meanings of the words " whole " and " hole " ! :-)
Posted 07 November 2011 - 08:14 AM
Sorry Kenny and others if this explanation is unclear. I do suffer from dyslexia and mild learning difficulties and the above post seem to read OK to me. I will post a few pictures of maybe a video if that would be of interest to anyone.
Posted 07 November 2011 - 10:48 AM
Posted 07 November 2011 - 11:26 AM
Ok a pictorial run through for dismantling a typical Porro binocular.
Posted 07 November 2011 - 11:28 AM
Posted 07 November 2011 - 11:31 AM
Then wind the focus wheel untill the focus thread unmeshes from the focus wheel.
Posted 07 November 2011 - 11:37 AM
Posted 07 November 2011 - 01:19 PM
I am genuinely sorry to learn of your reported " dyslexia " and associated problems , of which of course I had no idea about .
In spite of that , I'm surprised and somewhat taken aback by Bill's comment , given that , in spite of the content of so many of his posts and articles , I'd long been under the impression that he was an active member of some sort of " plain English " society ! :-)
I'll climb back into my " whole " now ! :-)
Posted 07 November 2011 - 01:41 PM
I don't make excuses for my dyslexia, I would rather be able to spell and read a book with the ease on others, but without dyslexia I would never have my binocular obsession!
Oh and the Swifts arrived today and their great!
Posted 07 November 2011 - 05:13 PM
Kennj of ALL people KNOWS that!
Butt, let me git serial 4 a mow ment:
I am SO glad some of you guys are beginning to SHOW members some of the ins and outs of bino repair!
Okay, seriousness off, back to Kenny . . . get a life. And, remember what Richard Berry taught me to say when surrounded "I'm an editor . . . not a proofreader!"
Posted 07 November 2011 - 05:37 PM
Lest you failed to notice , I already HAVE a life .......
........ as an amateur PROOF READER !
Your humble servant ,
Posted 07 November 2011 - 08:22 PM
Posted 08 November 2011 - 06:49 PM
Thanks for showing how to remove both eyepieces together with the center focus, all together. I ran into a problem once getting the focus wheel to "mesh" with the worm gear, so have been hesitant about messing around with the whole focus assembly. Before I undid the tiny set screw and removed the washer under the IPD indicator, I turned the focus wheel all the way in, so I had a reference point position for reassembly.
Perhaps next time I'll try undoing the screw via the front cap like you have shown in the photo.