It sure is good to have this forum back - the others (LUG/MUG) cannot compare!

Why is Leica going back to the brass top plate? What is wrong with a zinc top, it doesn't dent/deform as easily? What are the advantages of brass vs. zinc? Historically, how were the old M2/3/4/4P brass ones made. I don't think it is because of CNC (computer numerically controlled) machining for the following reasons:

1. CNC has a hard time cutting box corners (windows and ledges).

2. CNC has a hard time cutting malleable (gold/brass) metals thin unless done in a mold.

3. A lot of finishing is still required in order to take a finish (paint or plating) w/o showing machining.

4. Cutting from a solid block of brass seems uneconomical unless Leica remelts their own material.

Welcome Back!

-- chris chen (chrischen@msn.com), March 30, 2002

Answers

Brass is more stylish than zinc by far and although it's tougher to machine, there isn't that old school Leitz look without much brassing. Which now we can do to the M7. Of course, I never heard very often of zincing before to be honest.

-- Alfie Wang (leica_phile@hotmail.com), March 30, 2002.

Brass is stamped to shape.

-- Michael Darnton (mdarnton@hotmail.com), March 30, 2002.

to make it easier to produce black paint commemorative editions without running a separate line. and can you engrave a zinc top plate??

-- roger michel (michel@tcn.org), March 30, 2002.

My 1984 M6 is engraved, also has a film plane indicator; another difference with the Classic vs. the TTL.

-- chris chen (chrischen@msn.com), March 30, 2002.

See also the detailed entry on brass vs. zinc in the FAQ at:

nemeng.com/leica/ 042b.shtml

-- Andrew Nemeth (azn@nemeng.com), March 30, 2002.

Andrew,

I love your site, it's a gold mine of information. But, it also mentioned CNC being involved; could you elaborate?

-- chris chen (chrischen@msn.com), March 30, 2002.

I don't know the specific facts in this instance, but after a piece of brass is stamped to shape there are still lots of things for CNC to do--cutting the edges off, the holes for the windows, engraving, drilling screwholes, etc.

-- Michael Darnton (mdarnton@hotmail.com), March 30, 2002.

Michael,

CNC machines are different than other automated manufacturing processes. Assigning a 3-D CNC machine to do screw holes is not in the equation. A true CNC machine is mega-bucks which didn't exist in great numbers in the golden age of the M3/2/4...

Since Andrew is in the eastern hemisphere we will hva to wait for his source. And since threads die too fast he

-- chris chen (chrischen@msn.com), March 30, 2002.

Touch pad problem, AGAIN,

Since threads die quickly here, we may not get a complete answer until the thread is reborn, e.g., my "eyes" w/lenses question was not FULLY answered/solved still remains a mystery to me.

-- chris chen (chrischen@msn.com), March 30, 2002.

A couple of points:

1) Original brass tops - stamped. Zinc tops - spin cast. "New" brass tops - CNC machined. Summary of the TA note at nemeng.com.

2) Black chrome on brass tops (e.g. a few M4s, M4-2, most M4-P, M7) still 'wears' to a dusty silver undercoat v-e-r-r-y slowly. It will not show zorchie brassing like black paint because there's a silver chrome undercoat, and both black and silver chrome are VERY tough compared to black paint. If you want the 'brass-corners' look you MUST buy a black- paint camera - regardless of whether the underlying metal is brass.

3) My brass-topped Canadian cameras have very sharp 45-degree chamfers machined onto the edges of the top plates (e.g. where the flat top meets the flat front, and around the hot-shoe indent). The chamfers have a slight 'hand-hewn' look to them like they were done by a machinist using a grinder - not perfectly even, especially at the corners where two chamfers meet. All the M6 bodies I've seen just have smoothly curved edges.

-- Andy Piper (apidens@denver.infi.net), March 30, 2002.

Something didn't track in my last response - item 2). Obviously a camera has to BE brass to show brassing (duhh!) - but it ALSO needs to be painted, not chromed. As far as I know ALL black paint cameras are brass and all zinc top plates are chromed, however.

-- Andy Piper (apidens@denver.infi.net), March 30, 2002.

Andy Piper pretty much covers all the Qs here.

As for the black paint editions - yes, they must be on brass. The guy who does the repainting - Shintaro - talks about (and has photos of) the chrome being stripped from cameras before he hits it with the enamel. He used to say on his old site that he could only do brass cameras as zinc bodied ones would "melt" during the chrome removal process.

-- Andrew Nemeth (azn@nemeng.com), March 30, 2002.

so what was the point of having brass top-plates w/chrome surface coatings they will not wear like black paint bodies?????

-- summicron (summicron_@hotmail.com), March 30, 2002.

Andy,

You are certainly correct, mostly, but always thoughtful (I don't know a complete history). I too have noticed the hand finished quality and SLIGHTLY inconsistent contour nature of the older M's, it's inspiring and gives me confidence in the "adjust-to-perfection" craftmenship nature of the classic M's.

-- chris chen (chrischen@msn.com), March 30, 2002.