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Hollenbj
Tinkerer
Username: Hollenbj
Post Number: 52
Registered: 03-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, May 18, 2012 - 10:22 am: | 
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Hi Forum,
I have a IIIa with a mangled wind knob. I ordered a replacement from DAG (Don Goldstein) and it arrived in the mail recently. I removed the old mangled knob and proceeded to screw the new knob on the threaded shaft (as it pokes through the top plate, film counter, etc.
My problem is the new knob will not screw fully down onto the threaded shaft end. Looking closer at the old and new knobs, it looks like the old knob is indeed threaded a little further down/in than the new one. Also the machined step, where the circlip-like spring goes, is not as well defined. So, anyone encounter this variation in Leica parts? As I see it, I have a few options:
1. Attempt to thread further into the new knob. Not sure what that thread size is, or if a bottoming tap is available.
2. File/grind the threaded top of the wind shaft to be shorter.
3. Send knob back to Don and go through long process of trying to explain that I need a deeper thread, etc.
Advice?
BTW, I know I say "new" for the replacement knob, but its not actually new. That would be something.
Thanks.
j. |
Glenn
Tinkerer
Username: Glenn
Post Number: 998
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 19, 2012 - 07:33 am: |
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The renown Leica precision and longevity came about because all the cameras were assembled from hand picked parts - this ensured that normal machining tolerances were cancelled out and mechanisms always have minimum mechanical tolerances. Obviously this precision comes at a premium price. The advent of CAD and computer controlled machining probably cut down the amount of hand 'picking', however from articles in the photographic press at the time, it certainly appears that the M6 and possibly later M Series were assembled in this way.
Unfortunately from Jeff's description I do not think this is a case of machining tolerances - the 'poorly' machined location 'step' certainly does not fit with Leitz quality control. Also having built up a number early Leica 'bitsa' bodies over the years, I have never run into this problem. But, and it is a big 'but', all the parts in my 'bitsa' bodies always came from cameras with the same suffix letter. Thus if I found IIIc with a nice to mint vulcanite covering but poor chrome and mangled controls, the poor/worn bits were replaced by nice parts from a IIIc donor. So I cannot prove your knob is not off a later suffix letter III body.
I do wonder though if your 'new' knob did not start out life on one of the slavish Soviet copies of the Leica III's. Do not go and start shortening the shaft on the camera body, Always modify the 'iffy' part/assembly to fit the assembly with provenance as to the maker or series etc. In simple re-tapping jobs like this, just grind the end off a suitable taper tap so that you can bottom out the threads in the hole.
Personally I would send the offending knob back - I suspect the thing did not come for 'peanuts' and if sold as a IIIa knob it should fit your IIIa properly. Just say that it will not tighten down fully on the shaft because the threaded hole is not deep enough and let DAG sort it out. |
Hollenbj
Tinkerer
Username: Hollenbj
Post Number: 53
Registered: 03-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 19, 2012 - 12:43 pm: |
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Thanks Glenn,
I was considering options to sending the knob back because of shipping and the back and forth (and attempting to describe why I need a replacement). Don is good to work with, but between his busy schedule and the shipping times, it might (and I stress "might") be easier to work with what I have.
The knob is reputedly from a IIIa, and I believe Don attempted to send such a thing. I really don't think its from a Soviet clone.
So, with the advise I received, I will probably send it back. But if I did want to find a tap, any ideas what the specs are? In other words, what is the dia. and thread of the top of a IIIa wind shaft? I'm guessing someone here knows.
jeff. |
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