Extending Rise on Sinar Norma Front Standards

[Struan Gray]

Len, I can take a look at the threads on mine, but I won't have access to bolts and thread gauges until next week. I have a memory of the thread being a standard one, but it's quite possible I'm thinking of something else.

I would be surprised to find an imperial thread, but you never know. German and other continental manufacturers did use UK-inspired fine-pitch small diameter threads (BA series in particular) much longer than seems logical. Larger threads are almost always metric, except for things like garden hoses and spark plugs - neither of which is usually found on a Norma.

[Leonard Robertson]

Struan - I would much appreciate it if you can check the threads on your Norma and see what you think the size is. Part of my struggle is I don't have a metric micrometer so I have to measure in thousands of an inch then convert to mm and I never entirely trust my final answer. The metric thread spec charts I'm finding all read in mm so math must be done.

It is probably time to buy a 0-25mm mic. One of those easy to read electronic calipers seems attractive except for the need for batteries. Batteries and I don't get along well. The words I think of when I hear "battery" are "dead" or "leaky".

Something I never thought about before is the availability of aluminum stock and taps and dies in post-WWII Europe when the Norma was designed and first produced. Sinar may not have been able to buy exactly the material and tooling sizes they wanted, but rather designed around what was available to them. Maybe 3/8"X16tpi tap/die size was easy to find and a close metric size wasn't. I believe there were serious shortages of many things in Europe in the late 1940s.

If anyone has a tripod head with a removable 3/8" screw (such as a Gitzo), try threading it down into top of the Norma upright and see what you think of the fit.

Len

[Greg]

Just confirmed that a 3/8" tripod mounting screw fits perfectly...

[Jerry Bodine]

Checked fit using Sinar 3/8" screw to mount camera to Norma Pan-Tilt head. Good fit.
Checked fit using Gitzo 3/8" camera mounting screw. Good fit.
Checked fit using Leitz 3/8" camera mounting screw. Good fit.

[Struan Gray]

Feeling like a mea culpa is already in order......

3/8 is looking good. I'll check mine in case this is a Europe / USA thing.

[Leonard Robertson]

Thanks everyone for checking on the 3/8-16 thread size. At least I no longer wonder if I'm hallucinating. It occurs to me Sinar would have needed 3/8-16 taps on hand to tap the rail clamp for the tripod mounting thread. If that size thread was close to the size needed for the top of the uprights, why not use it? It is also a rather coarse thread so threading on upright extensions would be a bit quicker than if a finer thread metric thread was used. I know that seems a trivial advantage but who knows what may seem important to a designer or engineer?

The other odd thing I noticed - the outer diameter of the uprights is approximately 11mm. If they started with 12mm or larger rod with a rough surface finish, turning it down to 11mm for a nice finish seems possible. But the diameter I'm measuring of 0.433 inches is just slightly smaller than 7/16" (0.4375"). No way of knowing what size stock Sinar originally used for the uprights, but the almost 7/16" size is intriguing.

Len

[Greg]

The other odd thing I noticed - the outer diameter of the uprights is approximately 11mm. If they started with 12mm or larger rod with a rough surface finish, turning it down to 11mm for a nice finish seems possible. But the diameter I'm measuring of 0.433 inches is just slightly smaller than 7/16" (0.4375"). No way of knowing what size stock Sinar originally used for the uprights, but the almost 7/16" size is intriguing.

If you look closely the part of the standard under the rod and the rod are machined from one piece of metal.

[Leonard Robertson]

Greg - Thanks so much for pointing out the one piece construction. Somehow that seems like doing it the hard way compared to making the round uprights separate pieces, but who am I to criticize the father of Norma? At first I was thinking they machined this piece from a piece of bar stock, but it makes more sense that they would have started from a casting. It could be done either way but a casting would have been much less machining. On the other hand when they first started Norma production and were uncertain how many would be sold they may not have gone to the trouble of making a mold for castings. Fascinating subject to wonder about.

Len

[neil poulsen]

If you look closely the part of the standard under the rod and the rod are machined from one piece of metal.

That's impressive. I tried unscrewing the riser, thinking that it could be used to machine the extensions. Good thing that I didn't try any harder.

[barnacle]

One thought (from a position of complete ignorance): given that all the tripod fittings fit so well, is this possibly a 3/8 Whitworth thread? Close but not exactly the same as a 3/8-16. I'd suspect it would have been a more common thing to find in a European workshop than the US thread.

Neil