M7: black chrome = on brass; chrome = on zinc. True or False?

Sorry if this is a subject you've done to death -- I couldn't find any reference to it in

numerous related posts on 'finish' in the archived threads.... It regards the top and

baseplate construction on the black chrome vs chrome M7s.

 

KBCameras' website says of the M7:

 

"Classic Chrome - [snip] Chrome finish cameras and lenses are also heavier since they are

constructed from brass. An excellent choice."

 

"Black Chrome - [snip] When it 'brasses' it shows the silver colored zinc underneath. [snip]

This choice also makes for the lightest kit possible since Zinc is used for the top and

bottom plates of the camera and aluminum is used on the lens barrels. [snip]"

 

Is this true?

 

regards,

alun severn

AFAIK all M7s (and very late M6TTLs) reverted to brass top plates, which receive a zinc plating before the chrome plating goes on. Silver bodies probably show the same silver before they wear through to the brass as the black chrome ones do, but it wouldn't be noticeable. My late-model M6 Classic (ser#242-something) shows a distinct silvery "patina" on most of the edges. It was like that when I got it and I'm certain the camera wasn't heavily used before I got it, so probably it wasn't very well black-plated to begin with. Then again, some self-absorbed lunatic blacked out all the white engravings, I guess to make himself feel like an intrepid photojournalist, so for all I know he polished the camera with fine steel wool to fool people into thinking he'd really used it, as if anyone would care.

All M7 top covers are made from brass. The black chrome process starts with a zinc alloy like layer under the black finish (this is true for every black chrome over brass finish produced by Leica). This zinc layer is the first thing you see when the black chrome finish begins to wear. Further wear, however, will eventually reveal the brass base metal.

 

Although it has improved in recent months, KB's website is riddled with errors; most of these mistakes are due to dated information. All standard production M6 top covers were molded from zinc alloy. It makes sense that the very last M6 TTL top covers could have been brass, but there is no documentation to this effect I am aware of.

"Black Chrome - [snip] When it 'brasses' it shows the silver colored zinc underneath. [snip] This choice also makes for the lightest kit possible since Zinc is used for the top and bottom plates of the camera and aluminum is used on the lens barrels. [snip]"

 

This statement is only partially true. All M6 production cameras were made from zinc alloy (that includes both black and silver chrome). Therefore, silver chrome is no heavier than black chrome. Current Leica production camera top covers are carved from a solid piece of brass. Therefore, again, the weight of a silver chrome M7 or MP camera is respectively identical to a black chrome or black paint camera. However, black chrome lenses are made from an aluminum alloy and silver chrome lenses are made from brass. Therefore, it is true black chrome lenses are lighter than their silver chrome counterparts (some by a considerable margin).

black chrome make better shots,speshialy protect hands after mast-ion

Mark presents a good argument in favor of censorhip. :-)

Frank, frank, frank. :-(

I don't think he's Frank. Perhaps a distant relation though.

A (%%*&$#$#$ clone.

Brass vs. Zinc:<p>

 

<a href="http://www.nemeng.com/leica/042b.shtml">

http://www.nemeng.com/leica/042b.shtml</a>