Brass in chrome M6 cameras

[stric]

Hello,

Recently I was told that M6 cameras in chrome finish are made with

some brass and as such weight more than the black-chrome counterparts.

Is this true?

[Bill Blackwell Images]

No. There is no more brass in a silver chrome M6 than a black chrome M6. The top plate is a zinc alloy. All of the other (external) components, such as the RW knob, frame preview selector, the base plate, etc., are brass.

[Bill Blackwell Images]

BTW, because the base material is identical, there is no difference in weight between a silver chrome M6 and black chrome M6 of similar vintage.

[nemeng]

<i>I was told...</i><p>

 

FWIW here's a link to a topic in the Leica FAQ I maintain, which talks about brass bodied Leicas. As the previous poster pointed out, the M6 is not one of them. The very last chrome M6TTL's however, did use brass. Maybe the person who told you got confused?<p>

 

Here's the link:<p>

 

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

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

[nasmformyzombie]

One other point, there is a weight difference with most (if not all) newer M lenses. The chrome versions are heavier.

[jack_myovski]

IIRC, the silver-chromed M7 and MP bodies, as well as those end-run M6TTLs are all brass-based yet none of them outweighs its blackened counterpart. Evidently the zinc and brass bodies weigh the same. However in the case of the silver-chromed lenses IIRC there is a substantial weight gain as a result of the brass construction because in the case of blackened lenses, those are made from aluminium. Would that be correct?

[Bill Blackwell Images]

"...there is a substantial weight gain as a result of the brass construction because in the case of blackened lenses, those are made from aluminium. Would that be correct?"

 

Yes.

[kenny_c]

how do you know if a M6TTL is zinc or brass?

[Bill Blackwell Images]

"How do you know if a M6TTL is zinc or brass?"

 

Read Andrew's link. It would have to be a high numbered M6TTL (2,6xx,xxx or higher) to start off with. Otherwise, there is no easy way to tell and the brass numbered tops are not recorded as such.

[kenny_c]

Ah, mine is a 2,4xxxx.

[raymond_tai]

I have one of those brass M6TTL's mentioned in Andrew's excellent website. It came packaged in a paper inner box instead of the usual plastic clam shell. The chrome is duller and if you place it side by side with a chrome M7 and a zinc M6TTL it is obvious the top is exactly the same as the M7. I can only assume that Leica had dropped the zinc top to save costs since they were already stamping out M7 tops which had the same dimensions.

[lb-]

does it make any functional difference for the camera?

 

I have an M6ttl with a 27xxx serial number. how can I tell and do I care?

[kim yee]

M6 classic titanium is Brass, I think.

[Bill Blackwell Images]

"Does it make any functional difference for the camera?"

 

No.

 

"How can I tell and do I care?"

 

The first part of this question has already been answered and, no, you shouldn't care.

 

"M6 classic titanium is Brass, I think."

 

All special plating, including BP, titanium, platinum, and gold, were over brass.

[george_lambsdorff]

A conclusion:

 

- Older Ms (at least until the M6TTL came out) have a zinc top plate.

 

- The chrome lenses are heavier because aluminium cannot get a chrome surface in Leica-quality, therefore they use heavier brass in chrome lenses.

 

- All new Ms (all M7, MP but I'm not sure about the TTL - just the last ones?) have brass top plates. Nearly all outer parts of an M (also in the inside, like R8/9) are cnc-milled of a block. One of the most expensive ways but also the one with the best quality (tolerance < 1/100mm). The small company Clößner is doing this job (look at the other parts they make!) :

http://www.cloessner-gmbh.de/

 

You can differ the cameras by looking onto the edges, the cnc-millded top-plates are rather "sharp"-looking, espeacially in the corner in front of the time-wheel.

[torben_daltoft]

"Older Ms (at least until the M6TTL came out) have a zinc top plate. Not true

[Rob F.]

Brass is an alloy composed of copper and zinc. Copper has a higher specific gravity than zinc has. In other words, it weighs more. Therefore it follows that a brass Leica, containing some copper in its parts, must weigh somewhat more than an all-zinc Leica.

 

As to whether black lenses are aluminum, vs. chrome ones being made from brass. In actuality, both types contain some of both metals. Leica uses aluminum and brass because these two metals have a natural lubrication property, so that when one moving part is brass, and the other is aluminum, they move easily without binding or galling.

 

Brass can be chromium plated more successfully than can aluminum. Consequently, the outer part of the barrel is made from brass when the lens is to be chromed. The inner moving part is then made from aluminum, to obtain this desirable property.

 

But if the lens is to be painted, then the outer barrel can be aluminum, for a weight saving. The inner, smaller part can then be made from brass without the weight penalty that occurs when the larger outer barrel must be made from the heavier alloy.

 

So it's not a simple question of brass vs. aluminum. The truth is in the details.

[george_lambsdorff]

To prevent missunderstanding:

Not all Ms before M6TTL had zinc top-plates, they used an older technology to shape brass. I think the most M4P-M6 have zinc top-plates.

[httpphoto.netsharedco]

<p>The Silver MP top place is clearly of brass. My question is whether the chrome finish is applied directly to the brass or is there a layer of nickel applied to the brass first, then the chrome applied to the nickel.</p>