# Repairing a 25x100 binocular



## savarin (May 4, 2017)

A couple of years ago my 25x100 binocular fell out the back of a truck (fell out not fell off the back of) and broke in half.
A club member had a go at welding the little broken pieces back together but unfortunately not very well.
I was just going to keep then as individual finder scopes for my giant binocular (when I get back to making it) but yesterday I felt like a break from the powder coating oven and decided to see if I could repair them.
I had disassembled them two or more years ago so cant remember exactly how they go back together.



This is the broken ring



This is the repaired ring that doesnt look as if it will last very long



The fixing holes at the wide end are oval for some reason, I can only think that the two tubes do not move entirely parallel with each other and this is for clearance but I dont know for sure.



After some experimentation it looks as if all the parts go together like this.
The small screws are to hold the prisms in the housing. 



I think there is sufficient material to allow two new side plates to be screwed to the broken originals so I'm making a mandrel to pass through all four fixing rings to spot the centres of the new plates.
I will bore these to size as all four are slightly different diameters as the main fixing pin is tapered.
The spacer will then have to be shortened to fit in between them also.
I hope I can get them close enough to original as re-aligning the optical assemblies will be a difficult one.
Translation - I've never done this before.


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## savarin (May 6, 2017)

Made the two different transfer punches to mark the centres (not a mandrel as I said previously)
Started one side plate and filed it to shape then realised I would need a clamp of some type to hold it tight to the remains.
So today was just a quick and dirty toolmakers clamp.
Tapered the ends like this.



Only managed to make one screw though but it looks like it will work well.


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## savarin (May 7, 2017)

Its difficult to progress when your neighbor pops round to share a beer and stays for the afternoon.
A good time was had by all but I did manage to finish the other screw for the clamp.


heres a shot of the transfer punches I made earlier but forgot to photograph.


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## Silverbullet (May 8, 2017)

Are the broken parts screwed from the inside ? Why not remove them and make yours where they are? Should be strong enough.


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## savarin (May 8, 2017)

Unfortunately the whole tubing is a cast module in what I assume is a zinc alloy from the look and the way it drilled. I was contemplating filing the mounting blocks off flat and screwing the new ones on from the inside but decided it was way too much work.
(read too difficult for me)
Yesterday I bored the first one  and screwed it into place, semi assembled the two halves and it moved smoothly through its travel with no twisting or play so I have high hopes.


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## ch2co (May 8, 2017)

Gee, I've never taken something apart and then left the parts just sitting on a shelf for a couple of years. HA! I have several boxes with disassembled parts in them. 
Try to keep it all collimated. Otherwise you end up looking in two different directions at the same time. Crosseyed or at least with a headache after a couple of minutes
of viewing. 
Do you know what make and model it is?  Very fortunate that it was the case that broke and not any of the optics.

CHuck the grumpy old guy


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## savarin (May 8, 2017)

It looks like the optics didnt fair as well as I'd hoped, one of the eyepiece focusser units is also damaged. I need to get a good set of jewelers screw drivers for them.
I have two more damaged binoculars sitting here, a 25/40 x 100 Oberwerk and a bushnell 10x50.
The Oberwerk were given to me because they had taken a dive and smashed the lens hood and bent the casing making it impossible to unscrew the objectives.
I cut the damaged hood off and re-aligned the optics and they work well but are way too heavy for serious astronomy work.
The Bushnells are a mates that are so far out of alignment that its impossible to look through one side.
It looks like I may have found a small business if I can get them all working.


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## ch2co (May 9, 2017)

Just send the Overworks to me and I will use them astronomically. I'm just starting to build a heavy duty parallelogram adjustable height binocular 
stand for just this type of binocular i.e. BIG and heavy.  I love binocular astro viewing and spend a lot of time stretched out in my camping "chaise lounge"chair
sweeping the Milky Way for faint fuzzies whenever I can.  A cooler of cold beer next to me, the stars above me, it doesn't get much better for an old coot like me.

CHuck the grumpy old guy


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## savarin (May 9, 2017)

Well worth doing Chuck.
Have you thought of mounting the chair on a turntable?
Some small castors and two sheets of ply and voila.
I built a parallelogram mount for the 25x100 some years back around 2005.
I loved using it and at public gatherings it was brilliant and an extremely stable a viewing platform.
I could find the object then lower them for the kids to see without loosing the object.
I took the design from a book on building telescopes but cant remember the title.
This was well pre lathe time.
The tripod was made from standard pine section glued and screwed to form 
a "T" section and held to the top with three hinges, three gate hinges made the spreader/brace.
The central bolt was captive to one hinge and I kept a few wing nuts in the bag for the inevitable field loss at night.



The top was a disk cut from two layers of ply pinned and glued with teflon squares pinned with small panel pins and glue. The heads were set below the surface.


The swivel box was made from ply with a central spreader pinned and glued to a circle of ply with the good old ebony star  formica sheet "A la John Dobson"


The locking nuts were cut from 10mm aluminium plate and threaded.
Unfortunately this was not a brilliant success as they did unscrew . I will be fabricating a type of clutch system like I have on the refractor to replace this.
The parallel arms are light weight box section aluminium extrusions with plywood inserts so the bolt pressures wont crush them.
The pivots are just some mild steel rod with threaded ends. I will replace these with stainless in the refurb.



the view from underneath



To hold the binos I made a locking quadrant







The thumb nut needs replacing with a new version made in the lathe for a smoother action and locking/unlocking





The extended dew shields are black card and just slip over the original hoods and the rigel quick view is held on with two elastic bands.



Note how the rear end is short as I didnt want a long extension swinging around in the dark smacking into other people.
This necessitated to use of a heavy counter weight and rather than carry around a concrete block I cast a set of lead weights. 






They sat nicely in place on the end cross member and never moved irrespective of the angles.
Being individual weights it was easy to set them up.
The whole setup was very user friendly and made using the binos an absolute pleasure.
So 
I made and extension for the weights and a stronger head to hold the oberwerks.
Bad move, with the huge weight of the oberwerks and the extra lead plus the extensions produced so much inertia that they were horrible to use.
I need to re visit them and see if a 45' diagonal can be fitted so I can use them to see the sky.
Initial quick experiments seem to indicate this will not be an easy thing to do.


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## brino (May 9, 2017)

savarin said:


> Well worth doing Chuck.
> Have you thought of mounting the chair on a turntable?
> Some small castors and two sheets of ply and voila.



....and then you'd have a rotating Chuck!

Would he rotate different directions in the North vs. South hemispheres?

-brino


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## savarin (May 10, 2017)

brino said:


> Would he rotate different directions in the North vs. South hemispheres?
> 
> -brino



No way, same directions 
but upside down.


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## savarin (May 11, 2017)

filed out the brackets that I will screw to the existing flanges.
To bore them out I superglued them to a waste bit of ally plate.


My little boring tool is actually the internal threading tool bit but ti worked very well.


To drill the holes in the flanges required an extended drill bit because the wide part of the tube is in the way.
I made it for 4.2 at one end for the tapping size and 5mm the other end for the clearance hole.


First time assembled for I dont know how many years.
Not neat but it does work.


Now to dismantle again and clean the heck out of everything including all the optics then we will see if I got it right.


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## brino (May 11, 2017)

fingers crossed!


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## Bill W. (May 11, 2017)

brino said:


> fingers crossed!


Hopefully not the eyes too...


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## savarin (May 13, 2017)

Dismantled the eyepieces to find the wobbly part, sure is filthy in there.
Those three little pointed screws are all that holds the eye cup to the lens holder.



Here you can see where they have pulled out of the aluminium, This was why the end wobbled about.
An easy fix, just re-locate to a clean part of the barrel.



This is the prism assembly, only 6 surfaces to clean, no damage.



After reassembly of both sides it looked good and moved smoothly throughout the movement.


Now the hard part. Each tube looked good and clean except the right hand tube pointed to 2 o'clock and the left hand one pointed to 8 o'clock.
It took just over an hour to re-align them and get both tubes co-collimated but I got there and they are great to look through.
I'm lucky in that there is a radio mast about 12 kms away as a perfect alignment target as it contains vertical, horizontal and diagonal components so is easy to marry everything up spot on.
Tomorrows job is to re build the parallel mount to hold them.


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## savarin (May 14, 2017)

The mount is refurbed but I must have melted one of the weights for something as its missing, gotta do a lead cast now.
However, last night was its first light since the repair and it was awesome.
Four of Jupiters moons pin sharp, could just make out the bands on Jupiter, Omega Centauri was a huge puffy ball, M42 not bad, sharp, but not enough magnification.
For me they are perfect.
BUT, as soon as the inter pupillary distance is altered they go out of alignment and the dreaded double image pops up.
So, no one else can use them.
I must assume my hinge is slightly out because they pop back into alignment as soon as the IPD is returned to my distance.


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## Silverbullet (May 15, 2017)

ch2co said:


> Just send the Overworks to me and I will use them astronomically. I'm just starting to build a heavy duty parallelogram adjustable height binocular
> stand for just this type of binocular i.e. BIG and heavy.  I love binocular astro viewing and spend a lot of time stretched out in my camping "chaise lounge"chair
> sweeping the Milky Way for faint fuzzies whenever I can.  A cooler of cold beer next to me, the stars above me, it doesn't get much better for an old coot like me.
> 
> CHuck the grumpy old guy


Half dozen beers everything is fuzzy ain't it... lol


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## Silverbullet (May 15, 2017)

savarin said:


> The mount is refurbed but I must have melted one of the weights for something as its missing, gotta do a lead cast now.
> However, last night was its first light since the repair and it was awesome.
> Four of Jupiters moons pin sharp, could just make out the bands on Jupiter, Omega Centauri was a huge puffy ball, M42 not bad, sharp, but not enough magnification.
> For me they are perfect.
> ...


Geez sounds like you been in grumpys cooler too. Seeing double lol


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## OliverWilkins (Oct 14, 2020)

Great result in the end, but not everyone has the skill to repair and that is why I buy new when something gets broken. There are really good new things on https://www.atncorp.com/thermal-monoculars. Those guys are selling really good things. I had to save some money to buy a really cool scope that can even take HD videos and now I am waiting for their new thermal monocular. I love it when they have some giveaways, you can win some really great things.


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