[Leica] Re: M8 body shell

[glehrer at san.rr.com (Jerry Lehrer)]

Larry,

As a graduate metallurgist and an aircraft stress analyst, I shudder at 
your use of the word "crystallization"!  Let it be known that most
solid metals are crystalline.  Very few are amorphous.  In fact some RR 
gas turbine blades are made of a single crystal.

The rest of your statements are accurate.

Jerry


Lawrence Zeitlin wrote:
>
> On May 25, 2007, at 6:14 AM, lug-request@leica-users.org wrote:
>
>> grduprey@mchsi.com wrote:
>>> Daniel,
>>>
>>> Overall i would agree, but the single piece body is much costlier to 
>>> produce and probably repair.  Since everyone seems to beat on Leica 
>>> about the cost of initial purchase and repair costs, and the need to 
>>> reduce these in future products, this is probably why they went this 
>>> route.  Then again just about every other camera company uses this 
>>> method with little or no problem.  Another reason they probably did 
>>> it this time.  I am leaning on waiting to see what the analysis of 
>>> the failures shows at this time.  I am using mine on a hand grip 
>>> mounted to the m8 so i can shoot one handed, and so far it has 
>>> worked just fine with no indications of loose fit it stress.  I have 
>>> another 7 weeks to go before i have use of both hands again.  The 
>>> down side is it is very clumsy to work this way with the camera, and 
>>> one handed is not good for shakeiness.  ;-)
>>>
>>> Gene
>
>
> I may be mistaken but I thought that all RF Leica body shells from the 
> urLeica through the M7 were extrusions rather than castings. The body 
> chassis that holds the shutter, film transport, lens mount was either 
> an assemblage of stampings (Leica 1 through IIIb) or a die casting 
> (Leica IIIC through M7). I understand that Leica adopted the extruded 
> body shell because it was cheaper to make. A side benefit is that 
> extrusions are generally stronger and more ductile than equal wall 
> thickness castings. All the rest of the marketing hype about rigidity, 
> solidity etc. came as justification for the needle threading loading 
> process. Leica found no need to use fixed backs on any of its other 
> cameras.
>
> If the M8 body and shell is a die casting, the base plate attachment 
> failure may be due to an inclusion in the material or partial 
> crystallization (or poor design). I'm no materials expert but I did 
> serve as a consultant for a firm which made investment castings of 
> aircraft engine turbine blades and complex castings of pistol and 
> shotgun receivers. Flawed castings were not infrequent and parts used 
> in critical applications went through elaborate testing procedures to 
> identify minute cracks and flaws that could precipitate failure. It's 
> not only the glass that needs careful inspection and a high level of 
> quality control.
>
> Larry Z
>