What Imperial Thread Size Could That Be?

[Mechanola]

Hello, everybody



Mate and I arrived at the Siemens & Halske Telefongewinde (telephone thread) #31 of MD 2,160 mm, 51 tpi, and 68 degrees angle. The outer end of this set screw is botched, obviously. Looking at some tables now I see that there is #2 - 56 0.086" UNC size which would be 2,1844 mm OD. Siemens & Halske built Bell telephones early in their career, that made me think an Imperial size could have come to use. 2,16 mm is no man’s land with metric threads.

What makes it more difficult for me is the fact of a steel grub screw in an aluminium part. There are two, actually were, we had to drill one out, the other one had the clemency to turn. These are set screws in the sprocket drums transporting the film with a Zeiss-Ikon Movikon 16 camera. The Movikon 16 appeared in 1932, this examplar is from 1940.

Was or is there an 0.085" MD thread?

 

[Limy Sami]

Is it in World Screw Threads Guide to World Screw Threads: Amazon.co.uk: P.A. Sidders: 978925: Books

I haven't or have never see a copy, only been told it is THE reference on the subject.

 

[enginebill]

You might be able to find it here.
http://webcache.googleusercontent.c...BSgXK4J:www.watchman.dsl.pipex.com/thread.xls

 

[John Garner]

Mechanola --

The thread pitch, which you report as 51 TPI, strikes me as suspiciously close to 1/2 millimeter.

John

 

[Joe in NH]

You might be able to find it here.
http://webcache.googleusercontent.c...BSgXK4J:www.watchman.dsl.pipex.com/thread.xls

Thank you EB. That thread compilation is the most complete I've seen. Almost ALL known "standardized" threads are included.

The table is a little slow at the start, but by the 4th or 5th page you get into the more commonly known US sizes.

It is possible being a Swiss camera that it might be a "proprietary" thread - known and used only by that particular manufacturer. The Swiss were and are big on precision.

Joe in NH

 

[MattiJ]

Hello, everybody
... 2,16 mm is no man’s land with metric threads.

2,16mm would be close enough to be standard M2.2 but that one has 0,45mm pitch or ~56tpi

 

[JST]

Just from looking at the pic, it appears that the screw is a bit worn/corroded (It looks almost Whitworth in the pic, the threads do not look very good at all). If that is true, then any dimensions you get from it may be just "suggestions" and in no way absolute.

Nailing it down to a specific one may be tough or impossible. Perhaps making some guesses and trying them out with test pieces you thread might be the best way?

 

[Mechanola]

That screw is an insult to anyone working in fine mechanisms, we wondered long enough about having found such a bastard in a Zeiss-Ikon camera. The suspicion is that Siemens & Halske would have furnished the sprocket drums.

Zeiss-Ikon was a German incorporated company formed effective October 1st, 1925 in Dresden.

Many thanks for the links, very informative. For those unfamiliar with the first and only purely mechanical selfie camera, released in 1934, a picture of the innards:



You can preset the duration of a take between one second and a full wind which runs for 49 seconds at 16 frames per second, turn on the self timer, push the release button, walk into the scene within ten seconds, and see the camera start rolling by a falling piece of paper you previously have clamped under a hook at the camera’s front. The hook is pushed outwards by a stud in the lower sprocket shaft drive gear. The Movikon 16 sold for $385 in 1939 by Bass, Chicago, $6,800 as of today.

 

[ManicMetalBasher]

For sale on Amazon UK.
Zeiss Ikon Cameras, 1926-39 (Hove Collectors Books)
I do not know whether it has the thread sizes you want.

Also a site called Camerapedia, might be worth investigating.

There are probably more sources, I only spent two minutes online.
EG Zeiss!

 

[paul39]

You can preset the duration of a take between one second and a full wind which runs for 49 seconds at 16 frames per second, turn on the self timer, push the release button, walk into the scene within ten seconds, and see the camera start rolling by a falling piece of paper you previously have clamped under a hook at the camera’s front. The hook is pushed outwards by a stud in the lower sprocket shaft drive gear. The Movikon 16 sold for $385 in 1939 by Bass, Chicago, $6,800 as of today.

Pretty slick camera. I found this:

Zeiss Ikon Movikon 16mm Movie Camera

From the photos it looks to have through the lens viewing with a beam splitter behind the lens.

Paul

 

[Mechanola]

The beam splitting prisms are above the lens, they sit in that black block you slide to the right, seen from behind the camera. You also slide out a sight at the camera’s rear. Coupled with the lens barrel is a pair of rotating wedges that dissect the light into two images, the bulleye above the lens. When focusing you see the direct view image and the dissected one coincide on the object.

There were a number of rangefinders on the market before this camera, accessories such as the Leitz Instafocu, the US-made Dist, the Meyer Correctoscope which incorporated also a lightmeter, and from August 1933 on Bell & Howell’s Range Finder to the Filmo 70-D, allegedly very precise.

A more basic approach was assumed by Paillard with their rackover system, in fact rather a diagonal shifting of the H camera on a dedicated support. Racking the camera sideways was the classic focusing method introduced by Bell & Howell in 1912. A lens mounted in the four-port turret would occupy the same place above ground when turned to the right side in the camera slid to the left and turned to the left in the camera slid to the right side. Fast forward to 4:53

Zeiss-Ikon wanted to step ahead of all 16mm camera makers with a built-in rangefinder, yet some mechanical details were badly designed and or executed. Most of these cameras have serious problems today, one can easily slip into a $1,000 restoration. Bell & Howell Filmos age way better, at least as far as I can judge. I know the Eyemo, the Filmo 8s, the 2709 quite intimately, and some of the accessories. What the Movikon 16 really has alone is indefinite single-frame exposure without a cable release and direct access to the variable shutter disc. Any opening angle between 180 and zero can be set.

Back to the set screw, I see a #2 watch button thread of 0.085" - 84. The next close one is UNC #2 0.086" - 56. Maybe the watch button thread found its way to Europe and Siemens. Crazy things, threads, no?

 

[MattiJ]

Back to the set screw, I see a #2 watch button thread of 0.085" - 84. The next close one is UNC #2 0.086" - 56. Maybe the watch button thread found its way to Europe and Siemens. Crazy things, threads, no?

Why you keep looking for 0.086" - 56 UNC if there is Metric Standard M2,2x0,45mm

 

[Illinoyance]

I doubt you will be able to find a replacement screw in S&H size 31. You can try to make one or you can decide what standard screw to use as a replacement. The tap drill for the new screw needs to be a little larger than the OD of the S&H screw. (Engine Bill's reference lists the S&H threads)

 

[Mechanola]

I had to go on and decided to drill out the old thread, one sprocket drum is now secured with an M3 grub screw, the other one is still the original. Client wants to shoot with the camera, I want my money, too much work went into this already. Sometimes if not most of the times you can’t bust the myth people put on things. Somebody wrote about the Movikon 16: a German legend, there was nothing better around then.

The film guidance is very crude, the canal is 16,04 mm wide. No lateral spring. Due to a rather long pressure plate and additional force applied by a separate pressure frame opposite the gate the film is braked enough for acceptable image steadiness. The guide rollers on the sprocket drums are not guided exactly, their axles sit in elongated bores, a leaf spring behind them, the parts the hold this sit on movable plates again upon which pressure is exerted, and it doesn’t take much to bend everything out of alignment. If that happens the guide rollers foul the teeth of the drums, see yourselves:



I’m going to publish an article about the Movikon 16 with one or two fora (forums for non latiners), might add a link here.

 

[Mechanola]

Heres the link to my article in German: Bericht von der Generaluberholung einer Zeiss-Ikon Movikon 16 - Schmalfilm - Filmvorfuhrer

I can provide a translation on demand.