Archived posting to the Leica Users Group, 2003/10/30

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Subject: Re: [Leica] My Leica M digital solution
From: Frank Dernie <Frank.Dernie@btinternet.com>
Date: Fri, 31 Oct 2003 07:11:25 +0000

Hi Clive,
I know what you mean, Ti is about half the density of steel (ally a 
third approx) so if you are used to steel items Ti feels very light. 
Aluminium and magnesium are so weak and flexible and prone to corrosion 
and scratching that they are not very suitable for quality long life 
products. It is only necessary to compare one of the early natural 
aluminium barrelled rangefinder lenses (contax, nikon etc) to a 
contemporary chrome plated brass lens to see the difference in 
longevity. Brass is nice to machine, takes electroplating well and has 
very good friction properties. It is ideal for lens mounts except for 
its weight. I think even the anodised aluminium black Leica lenses use 
brass in part of the focussing helix.
I think the Leica M black rangefinder lenses are the best engineering 
compromise of all. The black anodic coat gives reasonable prevention 
from corrosion (but the base metal is so soft that the coating is 
easily worn off the high spots) The precision is high and weight low. I 
think a titanium barrelled lens would be almost pointless. It may be 
less prone to scratching - though unless it has some surface coating it 
would be prone to staining from finger marks etc.. It would be heavier 
than the black lenses (though much lighter than the chrome and ti oxide 
coated ones) and frighteningly expensive simply because it is so much 
more difficult to machine (the cost of engraving the numbers on a 
titanium barrel would be astronomical).
cheers
Frank


On Friday, October 31, 2003, at 03:16  am, Clive Moss wrote:

>
>> -----Original Message-----
>> From: owner-leica-users@mejac.palo-alto.ca.us
>> [mailto:owner-leica-users@mejac.palo-alto.ca.us] On Behalf Of
>> Frank Dernie
>> Sent: Thursday, October 30, 2003 4:55 PM
>> To: leica-users@mejac.palo-alto.ca.us
>> Subject: Re: [Leica] My Leica M digital solution
> ...
>  brass is  even denser than titanium.
> ...
>
> That was my point -- I would rather have titanium that brass -- where 
> it
> made engineering sense and saves weight. Titanium plated brass seems to
> be the worst of both worlds (weightwise -- it does seem to wear well).
> Every few grams counts. I am not a metallurgist, so I have no idea what
> the actual difference would be. Speaking as a consumer, my titanium
> stuff feels lighter than other materials. Maybe they also contain more
> plastic :-(
>
> -- 
> Clive
> http://clive.moss.net
>
> --
> To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html
>

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