potts34
sage
Reged: 12/09/08
Posts: 464
Loc: Derbyshire , England
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16.) Next undo the lockring on the objective end (GREEN arrows), you can VERY carefully use a pair of needle pliers end on( I have a specially shaped pair that have been ground to fit to remove these or better still a flat piece of metal shaped to fit in both slots at the same time, DO NOT contact the lenses.
IT IS advisable to put a piece of dense cardboard cut to fit over the lense if you do not have the correct tool to avoid damage to the lenses should your tool of choice slip.
17.) Now tighten the objective housing and then carefully turn the lense (YELLOW arrow)until it aligns with the light blue mark, the image SHOULD be good, retighten the lock ring and that is it really.
Now this is a fairly simple method with a basic kit of tools. The following need noting
1. early lense coatings are easily damaged, if I am unsure I just use boiled and cooled water to clean these.
2. you must be VERY careful removing screws, if you chew up or damage the head, finding replacements CAN be very difficult on rarer binoculars, make sure you clean all the paint out of the slot and use the correct size screwdriver for the screw head.
3. keep your work area clean
4. be realisitc can you do the job?
5. if it a very rare binocular or you are unsure consult a specialist.
6. practice on cheap common binoculars, an already broken pair are ideal for practice.
7. construction methods vary from country to country and maker to maker, ocular housings are sometimes held just by their main thread, sometimes by grub screws through the endplate/body-housings and sometimes with a lockring which may or may not have grubscrews in it also.
8. I have purposely left out the stripping and rebuilding of the ocular internals A. because it isn't always necessary and B. because there are many diferent types and methods of construction.
Suffice to say generally you remove the eye cup then the VERY small screws (usualy 3) that hold the adjustable knurled dipotre body in place- on some types this body splits where the dioptre marking are sometimes with a Left hand thread, there may be a small hole between the markings to get a pin spanner in to lock/unlock it.
Make sure if you do split an ocular to replace all the lenses in the correct order.
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The man who never made a mistake never made ANYTHING!
My Flickr page http://www.flickr.com/photos/9658763@N07/?saved=1
Edited by potts34 (11/22/09 04:30 AM)
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potts34
sage
Reged: 12/09/08
Posts: 464
Loc: Derbyshire , England
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Please comment on any obvious errors(Thanks Kenny),
I have no ego and will NOT be offended, my intention is to inform and help others not win medals.
There may well be spelling/grammatical errors etc but during the time it has taken me to post all this I have stripped and rebuilt the Dollonds in the pictures and they are now optically as good as they will ever be (at least for my eyes).
Have fun!
p.s I apologise for picture quality I have had to use my camera phone as my usual camera a Sony Cybershot DSC-T1 failed yesterday with a common fault I believe, something to do with a CDD or DCC chip $ 20(for postage) to get fixed free in the 'States', (offer until 30th November this year)no Idea over here as I can't get through to Sony UK/Europe despite trying for hours at all different times you just get put on hold etc, message tells you they are putting in a new computer system... I bet I get through after the free? repair offer is over??? rant over!
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The man who never made a mistake never made ANYTHING!
My Flickr page http://www.flickr.com/photos/9658763@N07/?saved=1
Edited by potts34 (11/21/09 12:45 PM)
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Simon S
professor emeritus
Reged: 01/07/07
Posts: 584
Loc: Crawley West Sussex UK
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I must highlight the importance of ensuring the prism is relocated in it's original housing and in the way it came out. It is amazing how much change in alignment will result in a prism inserted 180º .
Thanks Potts I will try to sort a video.
Oh and to get the º symbol, Hold down the ALT and type 167 on the numerical pad :-)
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My binocular collection recent first
http://www.flickr.com/photos/binoculars/
My binoculars in Alphabetical order http://www.flickr.com/photos/binoculars/sets/72157613812824211/detail/
Over 2000 years of history in my cupboard!
Edited by Simon S (11/22/09 05:11 AM)
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1871
Loc: Connecticut
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I wish I had realized how important it is to replace each prism in the same position and orientation before taking my first binocular apart. I think the number of different combinations is 8!, but my statistical math is a bit rusty. That's more than 42,000 different ways to put a porro binocular's prisms back together.
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
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Jonathan B.
journeyman
Reged: 05/22/07
Posts: 6
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Potts:
Fantastic. Thank you. Already you have explained how to avoid some of the hazards I feared. I also used to work on racing bikes (sold them in recent years), plus automobile engines, transmissions, etc. I always attempted to tackle something without being fearful, but a little fear keeps one focused.
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Simon Debrux
member
Reged: 07/21/09
Posts: 33
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Great job Mr Potts! I am sure you make it sound simpler than it is in practice but at least now I know the principles I can experiment.
One question: how do you decide which objective to start with when you are collimating? I suspect most of the bins I have come across that are badly out of alignment are the result of someone taking them apart and putting the prisms back incorrectly, then selling them because they can't work how to fix them. In most cases are the upper and lower prisms the same size. If not it cuts down on the 42,000 (!) permutations and saves a lot of time.
Also where can one buy a pin spanner? I have looked in a number of tool shops and on the net and the name seems to apply to a number of different implements.
Thanks again, Simon
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potts34
sage
Reged: 12/09/08
Posts: 464
Loc: Derbyshire , England
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Hi Simon, chances are if the bins are badly out of allignment then someone has usually put one of the prisms back in the wrong way round or cross threaded an objective or ocular, the cross threading is easy just unscrew and refit carefully(I have only had one to badly damaged too reuse)
For the prisms just remove each one, turn it round and look again if it is still out, you may get lucky.
I have found that generally prisms should be equidistant in their recesses.
Also generally prisms are the same size ,that said occassionaly you may get one 'end' where the prisms are a bit larger.
Pin spanners can be picked up at any good tool shop etc.
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The man who never made a mistake never made ANYTHING!
My Flickr page http://www.flickr.com/photos/9658763@N07/?saved=1
Edited by potts34 (11/23/09 02:35 PM)
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Simon S
professor emeritus
Reged: 01/07/07
Posts: 584
Loc: Crawley West Sussex UK
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Well I finaly have a pair of Silvarem's, a great model although this pair have not been particularly well looked after. Lenses are slightly scratched despite seller stating lenses scratch free.
I think I will buy a good pair later, these were cheap so i'm not bitter.
Oh and the final picture is a strange British model thats been sitting in the loft. Poor performance and suffering bad C.A.
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My binocular collection recent first
http://www.flickr.com/photos/binoculars/
My binoculars in Alphabetical order http://www.flickr.com/photos/binoculars/sets/72157613812824211/detail/
Over 2000 years of history in my cupboard!
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Simon S
professor emeritus
Reged: 01/07/07
Posts: 584
Loc: Crawley West Sussex UK
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And the second binocular, the Vismax 8x30
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My binocular collection recent first
http://www.flickr.com/photos/binoculars/
My binoculars in Alphabetical order http://www.flickr.com/photos/binoculars/sets/72157613812824211/detail/
Over 2000 years of history in my cupboard!
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potts34
sage
Reged: 12/09/08
Posts: 464
Loc: Derbyshire , England
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I like those Vismax Simon, guess 50's? they look sort of Ross -ish? the top prism covers especially so and the axle end screw. What's the image like through them?
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The man who never made a mistake never made ANYTHING!
My Flickr page http://www.flickr.com/photos/9658763@N07/?saved=1
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Simon S
professor emeritus
Reged: 01/07/07
Posts: 584
Loc: Crawley West Sussex UK
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No potts no idea, but some things I like about them, some not.
Collimation system is great feel built proof in the hands, but on the down side they are cold to the touch, poor optically and the objective lens is dangerously close to the end of the dew shield.
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My binocular collection recent first
http://www.flickr.com/photos/binoculars/
My binoculars in Alphabetical order http://www.flickr.com/photos/binoculars/sets/72157613812824211/detail/
Over 2000 years of history in my cupboard!
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brentwood
Pooh-Bah
Reged: 11/04/05
Posts: 1278
Loc: BC Canada
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That 'British made' looks a bit odd. Technically, they could have been made in Hong Kong prior to 1997!
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Big telescope.Small telescopes.
Ridiculous binocular collection
I've cut it twice and it's still too short.
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potts34
sage
Reged: 12/09/08
Posts: 464
Loc: Derbyshire , England
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perhaps they originally had a rubber coating/covers?
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The man who never made a mistake never made ANYTHING!
My Flickr page http://www.flickr.com/photos/9658763@N07/?saved=1
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Simon S
professor emeritus
Reged: 01/07/07
Posts: 584
Loc: Crawley West Sussex UK
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I had a pair a few years ago and they were exactly the same. I think this is the final product although I could be wrong. Brentwood you have a good point but they have that British build about them!
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My binocular collection recent first
http://www.flickr.com/photos/binoculars/
My binoculars in Alphabetical order http://www.flickr.com/photos/binoculars/sets/72157613812824211/detail/
Over 2000 years of history in my cupboard!
Edited by Simon S (11/23/09 03:54 PM)
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potts34
sage
Reged: 12/09/08
Posts: 464
Loc: Derbyshire , England
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They definately appear British to me also Simon they just have that 40's-50's look about them IMHO, so what holds the prism wedges in place?
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The man who never made a mistake never made ANYTHING!
My Flickr page http://www.flickr.com/photos/9658763@N07/?saved=1
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Simon S
professor emeritus
Reged: 01/07/07
Posts: 584
Loc: Crawley West Sussex UK
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Quote:
They definately appear British to me also Simon they just have that 40's-50's look about them IMHO, so what holds the prism wedges in place?
The two holes in case have set screws that push on the prism wedges. All you need to do is loosen one screw and tighten the other. The prism slides along the shelf and it works wonderfully. I wonder if these sort of ideas are patented?
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My binocular collection recent first
http://www.flickr.com/photos/binoculars/
My binoculars in Alphabetical order http://www.flickr.com/photos/binoculars/sets/72157613812824211/detail/
Over 2000 years of history in my cupboard!
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potts34
sage
Reged: 12/09/08
Posts: 464
Loc: Derbyshire , England
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If I remember correctly a WW1 vintage Crown Optical 6x 30 has a similar sort of an arrangement whereupon the copper?prism cover/light shield has a recess each side that moves the prism from side to side when the grub screws are turned, proper screws as well not little tiny screws but proper screws, the copper prism shield also stops damage to the prism unlike other systems B&L for instance.
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The man who never made a mistake never made ANYTHING!
My Flickr page http://www.flickr.com/photos/9658763@N07/?saved=1
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GlennLeDrew
Carpal Tunnel
Reged: 06/18/08
Posts: 1639
Loc: Ottawa, Ontario, Canada
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Potts,
When re-installing prisms, it's also important that they be properly squared up. If the 'slot' into which a prism lies allows any rotational movement at all, simply plunking the prism into place will likely result in some amount of image rotation. This is an important aspect of the collimation process.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery (mostly DIY stuff)
Simple minds discuss people. Good minds discuss events. Great minds discuss ideas. - Hyman Rickover
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Simon S
professor emeritus
Reged: 01/07/07
Posts: 584
Loc: Crawley West Sussex UK
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I remember working on an old pair of Tasco's wondering why they strained my eyes so mush despite the horizontals and verticals seeming in alignment. It was some time till I discovered that with a vertical pole in the centre frame, the image was merged at the top and out in the horizontal at the bottom. It can be very difficult to diagnose until you have seen it for the first time.
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My binocular collection recent first
http://www.flickr.com/photos/binoculars/
My binoculars in Alphabetical order http://www.flickr.com/photos/binoculars/sets/72157613812824211/detail/
Over 2000 years of history in my cupboard!
Edited by Simon S (11/24/09 03:33 PM)
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potts34
sage
Reged: 12/09/08
Posts: 464
Loc: Derbyshire , England
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I agree Glenn that's why I suggested it was a fairly simple (rough &ready) way of doing things, it's up to the individual to decide if they are competent if not it's an expensive trip to the specialist which will very often cost more than the binocular is worth, fine if you got the binocular cheap or free but if you paid good money to start with then it begins to get expensive.
The only way to learn how things work is by studying /rebuilding them and to be fair binoculars are not rocket science once you know the basics at least models up to the mid 1980's are pretty easy to work on IMHO.
A useful book on the subject of binocular astronomy is
'Binocular Astronomy' by Stephen Tonkin in the Patrick Moore Practical Astronomy series isbn 1-84628-308-6 it covers all the basics and has a pretty decent section on binocular optics and mechanics.
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The man who never made a mistake never made ANYTHING!
My Flickr page http://www.flickr.com/photos/9658763@N07/?saved=1
Edited by potts34 (11/24/09 03:23 PM)
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