Wartime IIIc film cassette problem

[colyn]

I have a wartime IIIc (1941-42) that will not work with the Leica M film cassettes. However my post war IIIc and IIIf work fine with these cassettes.

The wartime IIIc will work with the FILCA cassettes and store bought film but not the M cassettes. I tried my 1936 vintage IIIa with the M cassettes and it worked fine.

I measured the take-up spools on all of them and they are all the same size etc.

Anybody notice this with your wartime or pre-war Leicas?

 

[payasam]

This is strange. The older cassettes are 2.2mm longer than the new ones and, for that reason, will not work with M cameras. The M cassettes should work with all screw bodies. Perhaps the war-time IIIc was modified in some way?

 

[Xmas]

Colyn

The depth of the cassette housing is larger in the LTM cameras than the DIN/ASA standard. I dont know where the datum point for a cassette is, it will be recessed, i.e. at top of camera. I'll pull a film from my late IIIc and look.

Noel

 

[colyn]

This is strange. The older cassettes are 2.2mm longer than the new ones and, for that reason, will not work with M cameras. The M cassettes should work with all screw bodies. Perhaps the war-time IIIc was modified in some way?

I thought it might be modified in some way so I got my calipers out and made a number of measurements and compared them against my IIIf and they were within the same tolerances but whenever I try to use a M cassette it eats the sprocket holes on the film. The FILCA cassettes and store bought film work fine though..

I also removed the crate from the shell to get a better look and saw nothing out of order.

 

[colyn]

Colyn

The depth of the cassette housing is larger in the LTM cameras than the DIN/ASA standard. I dont know where the datum point for a cassette is, it will be recessed, i.e. at top of camera. I'll pull a film from my late IIIc and look.

Noel

The FILCA is a bit taller than the newer M cassettes but if that is the peoblem why do they work in the IIIa which is even older than the IIIc?

 

[Xmas]

The M casettes are to the '32 DIN/ASA standard and will have 2.2 mm of space to rattle up and down in. This will offset the film in the frame and might cause sprocket hole damage.

Do you have the IIIf finger enhancement?

The concentric cassette follower may not pick up on the lock drive slot...

Noel

 

[Xmas]

Double post

The late cassettes might not work in any of the LTM leicas they are 2.2mm too short. They may not open.

Store bought cassettes ditto but they will allow the film to get off the rails, unless someone has connverted to IIIF, i.e. installed a finger on the base plate to push the film up.

If you depth gauge the black and silver knob cassettes in the camera are the flats on the knobs at different depths, by 2.2mm?

Noel

 

[colyn]

Double post

The late cassettes might not work in any of the LTM leicas they are 2.2mm too short. They may not open.

Store bought cassettes ditto but they will allow the film to get off the rails, unless someone has connverted to IIIF, i.e. installed a finger on the base plate to push the film up.

If you depth gauge the black and silver knob cassettes in the camera are the flats on the knobs at different depths, by 2.2mm?

Noel

Problem fixed..
I swapped the bottom cover from my IIIf and it works fine.
The key that engages the knob on the cassette would not open/close the cassette so I swapped it for one from a parts door and it works..

The edges of the later model slots were turned up in order to catch the knob on the cassette. The older one is flat at the edges which was allowing the cassette to slip upward thus not allowing the cassette door to open/close.
See attached photo.
Door on the left is from my IIIf which shows the turned up edges while the one on the right is from the IIIc and has flat edges.

 

[Xmas]

Colyn

I thought IIIfs had an extra finger on bottop plate - is that an original bottom plate and does you IIIf have a hole for a finger?

Measuring my camera was strange the shorter cassettes seemed to not penetrate the camera as much so the follower for either casette type was almost at the same height, Ill have to review this.

Noel

 

[colyn]

Colyn

I thought IIIfs had an extra finger on bottop plate - is that an original bottom plate and does you IIIf have a hole for a finger?

Measuring my camera was strange the shorter cassettes seemed to not penetrate the camera as much so the follower for either casette type was almost at the same height, Ill have to review this.

Noel

The finger you refer to was not introduced till serial number 570xxx. Mine is 547xxx.
I have a bottom plate from the newer batch with the finger and plan to have my IIIf modified to accept it.

 

[Xmas]

Colyn

Information junkie fix received, I'll be on a high all night here... Ta

Wont you also have the IIIc done as well? Since I only use the leitz cassettes I dont get the off set photo frames, and am not bothered.

Noel

 

[colyn]

Colyn

Information junkie fix received, I'll be on a high all night here... Ta

Wont you also have the IIIc done as well? Since I only use the leitz cassettes I dont get the off set photo frames, and am not bothered.

Noel

I may have the IIIc modified also.