Tiny plastic screw for Nikon Ftn finder

mmerig · Jul 6, 2025

I need a small plastic screw to hold switch levers on a Ftn viewfinder. I tried a metal one and it grounds the current, so I need one like the one that remains near it. Here is a picture:

Anyone know where I can get one, short of buying a non-working finder?

mmerig · Jul 6, 2025

It's actually a TN finder, not FTN (it has an N near the on-off button and the linger slot for the iris switch coupler).

4season · Jul 6, 2025

Does that screw function as a guide, keeping the leaves of the switch in correct alignment? If so, any number of improvised solutions might work very nicely, such as a small bamboo rod. Not too enthused about seeking an exact, vintage replacement, as we're talking about plastic that's more than a half-century old.

MartinCrabtree · Jul 6, 2025

You can look here if you know the size/pitch needed.

mmerig · Jul 6, 2025

Thanks for the help.

The screw holds the switch leaves tight against the housing. The diameter is about 1 mm, and the McMaster source starts at 2 mm (I had looked at that weeks ago, but forgot about it as they did not have the right size). Thanks for pointing that out though.

I may be able to use a metal screw with a tiny insulating washer. It's not a big deal, it only matters for the battery check. The meter works fine otherwise. I think the plastic screw that remains is in good shape. It is not exposed to sunlight so that probably helps preserve it. The camera was made in 1967.

mshchem · Jul 7, 2025

I knew a guy who had at least 10,000 old broken cameras he used for parts but he finally closed a couple years ago. KEH doesn't sell parts but I bet they would be willing to take a bunch of your money to repair. I wonder if it's a one off (I doubt it) or a standard size JIS ? type of a screw??? I like the idea of a tiny plastic washer for insulation.
This kind of thing drives me nuts

RalphLambrecht · Jul 7, 2025

4season said:
Does that screw function as a guide, keeping the leaves of the switch in correct alignment? If so, any number of improvised solutions might work very nicely, such as a small bamboo rod. Not too enthused about seeking an exact, vintage replacement, as we're talking about plastic that's more than a half-century old.

they seem to be of Nylon. So, half a century old won't cause any problem.This stuff lasts virtually forever.

4season · Jul 7, 2025

If need be, M1 taps/dies can be had pretty cheaply, and I imagine that a 2 mm screw could be shaved down and rethreaded.

MartinCrabtree · Jul 7, 2025

Turning nylon that small would be a nightmare.

mshchem · Jul 7, 2025

Probably not rare just hard to find.

eli griggs · Jul 7, 2025

I like the idea of using bamboo or boxwood or lignum vitae for a screw.

The ligumn (genuine) is oily and is super dense, being used as baren material for centurie, including today.

Difficult to find in larger pieces, a small piece carved into a blank can be made by driving a piece through a piece of drilled steel, and passed through a metal tap and die, die.

Toothpick thick, it should work for years, IMO.

reddesert · Jul 7, 2025

You can buy nylon screws in SAE 0-80 (about 1.5mm) or possibly 1-72 (about 1.8mm) from McMaster-Carr and probably other places. When you get to these small screw sizes, an SAE fine UNF size tends to be very close to a standard metric coarse size. For example, SAE 0-80 is close-to-not-quite M1.4x0.3mm (sort of in between that and M1.6x0.35mm), and SAE 1-72 is very close to M1.8x0.35mm. I don't have this stuff memorized, I made a table of screw sizes sometime ago that allows looking it up.

Because this is a tiny plastic screw, I would be ok with screwing an SAE screw that is a little off into the piece. The metal parts are likely to just reshape the screw threads a little. If no screw metric or SAE can be found, I would consider just shaping a little plastic rod to about the right size and turning it in, letting the metal grab the plastic. It might hold for another 40 years.

mmerig · Jul 10, 2025

I used a small piece of black electrical tape as insulation and that worked. I just poked a small hole in the tape at the screw hole and used a metal screw instead of plastic.

Tiny plastic screw for Nikon Ftn finder

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