Success!
Chuck ...... You beat me to the post. I also received my hinge pin wrench yesterday evening and tightened up the hinge last night after a quick trip to Harbor Freight for a new screw driver set. While you were fixing yours this morning, I was taking photos for this post. My plan was to get this posted before you started yours so the job would be easier for you. I figured it would take longer for you the get the wrench.
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The biggest problem I found with this little project had to deal with the set screw holding the adjustment ring in place. The set screw is recessed inside a very small diameter hole in the adjustment ring.
My original plan was to use a quality gun smith screw driver set to loosen the set screw but the smallest flat blade was to large to fit inside the recess.
Next I attempted to use a small jewelers flat bladed screw driver but the set screw was in there so tight that I could not get it loose. The handle diameter on the jewelers screw driver was way to small to get enough torque to loosen the screw. It appears Nikon may have used a wax or some substance to help keep the screw in place.
I then went to Harbor Freight to pick up a 34 piece precision screw driver set that had a larger handle so I could get some more torque on the screw.
This ultimately worked. This was not the best screw driver for the job because the blade is thinner than the screw slot so there was some play. I would rather have a higher quality screw driver in the future if I can find one. One thing that helped was to move the screw out just a small amount then turn it back in. This working it slowly in and out got the screw loose without forcing things and causing damage.
After getting the screw to rotate about a third of a turn, it was loose enough to rotate without issue. I did not remove the set screw all the way, but just to the point where the top of the screw was protruding above the ring.
If you go with the Harbor Freight setup be sure an use the long extension inserted all the way into the hande. If you try to put just the blade bit into the handle, it will slip inside the chuck. It is necessary to press with some force so the blade does not jump out of the screw slot and cause damage to the screw head.
Here is the setup ....
The blade I used was labeled "1.5" which I assume means 1.5 mm. One of the screw drivers I tried to use from the jewelers set was 1.2 and it was to wide to fit the recess. So the exact size is variable depending on the manufacturer of the screw driver. It appears anything larger than 1.5mm would not fit. Anything less than 1.0mm would be to small.
Here is the pin wrench that I got off of eBay that I mentioned in an above post. There are no instructions. It came with two small black set screws not shown in the eBay listing. I used those to lock the pins in place rather than the larger screws so that there would be extra clearance (although not necessary). That left me with two extra unused larger screws. Also of note is two of the large screws are longer than the other four. The longer screws are needed to set the top cross bar because those are longer holes.
Tightening the adjustment ring was relatively easy. The wrench fit fairly well. It was easier to make the adjustment with the IPD adjustment of the binocular set to the most narrow position. This provided more clearance. The pin bars of the wrench were long enough so the cross members cleared the objective tubes. The fit inside the ring holes was somewhat loose, but not a problem at all. I had no issues with the wrench.
On Edit: A careful look at the first photo of the adjustment ring shows that some of the small holes in the ring are machined with threads. It would be best to insert the pin bars of the wrench into the small unthreaded holes so as to not possibly damage the threads of the threaded holes.
The ring was already very snug so it did take just a little bit of pressure to rotate it. I would put pressure on the wrench till the ring moved a little and then I would check the hinge tightness. this took about three iterations before I quit. I did leave things slightly on the loose side. The ring rotated about 8 degrees total. The ring rotation direction is clockwise to tighten. Retightening the set screw was now easy.
Difficulty: It is harder than changing a light bulb but it is not that bad for anyone with basic mechanical abilities and who is careful. As mentioned in an above post, having the right tools makes things a lot easier. The other secret is to go slow and do not force anything. The only real issue I had was with the set screw and that may be unique to my unit. A proper screw driver would make that much less of an issue. Suggestions on method and a better screw driver are welcome!
The hinge tension is now much better and it was worthwhile to make the adjustment.
