How Interchangeable Are Parts Between M Film Cameras?

[ktmrider2]

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With the debut of the new M6 and all the debate on this forum about interchangeable parts between the MP and M6 I am wondering how interchangeable parts are between the various M film cameras.  Let's leave the M5 and CL as well as the digital bodies aside for a separate discussion.

It seems to me that a shutter mechanism from an M2 may very well fit a new M6.  The speeds are the same, the sound is the same, the top and bottom speeds are the same, and the synch speed is the same.  And I think the shutter curtains are all made of the same material.  They move in the same direction on all the M film cameras.  Are the parts interchangeable?  I am willing to bet Leica does not design a new shutter when a new model is introduced.

The same can be said about the focus mechanism except for the various frame lines and slightly different magnifications on the limited .58/.85 viewfinders of the M6.  Leica did not redesign the viewfinder for each model camera.  I would bet that the "new" viewfinder on the MP and new M6 is simply the return to the viewfinder of the M4 and M5 and maybe the M2 before Leica tried to cut costs by removing one of the condenser lenses from the M4-2, M4-P, M6 and M6TTL cameras.  I sure would like to know if I am wrong.

The viewfinder frame lines preview lever would be using the same parts on all cameras after the M4 except there is a small variation in the shape of the preview lever. And the film advance is identical on all cameras after the M4 so is the drive train identical as well as the take up spool?  I know steel gears were used in some models and brass gears were used in some models but are the gears cut identically?

We can speculate about the new M6, the MP and the MA but I would sure like to know the facts.   How many times have I heard that the M6 is basically an M4-P with a meter?  I am not complaining, in fact for from it.  If something works and works well, why change it?

Any Leica M repair people out there who would like to comment?

[Huss]

The M7 has several bits which are quite different, from the meter readout to the shutter timing, but there may still be bits like curtain material, wind and rewind mechanism, rf mechanisms etc that are shared.

The M7 does not get enough credit for its hybrid shutter.  125 and 60 are mechanical which with a fast lens provides a pretty wide exposure envelope.  Pro AE cameras like the Pentax LX and later the FM3a did offer more,  but the Nikon F3 which was the dominant pro camera at the time offered only 1/90.

But I digress.

[madNbad]

The baseline should be how many M4 parts were used in the M4-2? When it was introduced in the late 1970s, the M4-2 is the basis of film Leica cameras till today. The change to steel gears and a new way of assembling cameras are still present. There have been improvements and changes over the years but the M4-2 marks the dividing line between the hand fitted cameras and every M camera that followed it.

[Anbaric]

For what it's worth I sent a brief query to Leica the other day, asking whether the arrival of the new M6 changed the availability of meter circuits and top plates for the old one, and got this response: 'the new M6 and the old M6 do not have any compatible parts'.

[Huss]

5 hours ago, Anbaric said:

For what it's worth I sent a brief query to Leica the other day, asking whether the arrival of the new M6 changed the availability of meter circuits and top plates for the old one, and got this response: 'the new M6 and the old M6 do not have any compatible parts'.

You should also have asked if there was any compatibility of parts between the new M6 and the MP.