Re: Compound shutter sizes
Ole, you best link to this thread in your signature. That way people can always refer to it :)
Re: Compound shutter sizes
Re: Compound shutter sizes
Nice idea Ole. Are those thread sizes 'really' t.p.i., or are they metric sizes translated into imperial units?
Re: Compound shutter sizes
Those thread sizes are really t.p.i.
Those are the data taken directly from the book, and thus from the original specifications. The 29 1/13 tpi is very close to .75mm, which is what SK Grimes use.
The 40 t.p.i has a 64° pitch, the 29 1/13 t.p.i. has a 50° pitch. Don't ask me why... :)
Re: Compound shutter sizes
Is it time to put this info up on the front page of this site as article? That would save peole searching for it.
Re: Compound shutter sizes
47.5° is the old BA standard for fine screws and bolts. The thread profile was used for wide-bore precision threads too, so I suspect the 50° comes from there.
64° seems odd, but then instrument makers are a funny bunch.
Re: Compound shutter sizes
I'll add the three types of "standard" Compur 2, too - same format as above:
Compur 2-X Tube 5/I
Compur 2-X Tube 5/II
Compur 2-X Tube 6/II
2-5/I : A: 45.8 x 40 t.p.i. B: 50 x 29 1/13 t.p.i. C: 35 D: 80.5 E: 35 F: 14.6
2-5/II: A: 45.8 x 40 t.p.i. B: 50 x 29 1/13 t.p.i. C: 35 D: 80.5 E: 25 F: 8.3
2-6/II: A: 49.65 x 40 t.p.i. B: 55.8 x 29 1/13 t.p.i. C: 35 D: 80.5 E: 30.8 F: 12.2
Re: Compound shutter sizes
Ole, here are a few more Compurs and Compounds that I have discovered while researching the old Symmars:
II or II S (Xenar 165/4.5, Xenar 180/5.5, Angulon 165/6.8)
II 4/2 (Xenar 135/3.5, Tele-Xenar 270/5.5, Symmar 210/6.8)
II 6/1 (Symmar 240/6.8, Symmar 270/6.8)
III 8 (Symmar 300/6.8)
Those are all from the 1935 US catalog. Post war, the lenses had either disappeared or changed to one of the sizes you mention.
The only one of those above that I own is the 270/6.8 Symmar (actually a 27cm from 1928). Dimensions are the same as the 2-6/II except E=41.3 & F=19.