Reassembling the Zenit B

[John Farrell]

The main gear assemblies have been cleaned with white spirit. I need to lube the shutter shafts (with Singer sewing machine oil), and then put the shutter together.

The brass piece to the right is a jig I made some years ago, when I worked on another Zenit. It holds the tops of the shutter shafts; the bottoms go in the camera shutter plate. It should make gluing the first curtain ribbons easier.

[John Farrell]

I have the shutter back in the camera - whether it works, remains to be seen. I think I have overlapped the two curtains a little too far.



I bent up a piece of copper wire, to lock the two shutter drums together, and to support the alignment tool I made.



The shutter with the alignment tool in place.



The first curtain ribbons tacked to their drum. I let the glue dry before completing the gluing of the ribbon around the drum.
You can see the overlap of the curtains, on the left.

[John Farrell]

Making progress.



The workspace; one end of the dining table.
These days I have to wear a pair of +3 hobby glasses to see close up.

[John Farrell]

After some fiddling, and a bit of thought, I've fitted the mirror to the Zenit. The mirror lift mechanism of this camera is unusual - it relies in a cam, which pushes up a pin, linked to the mirror through a lever mechanism. When the camera is wound, the pin runs under the cam. When the shutter is fired, the pin rides up the cam, and then drops off when the shutter completes its travel. The cam has its own driving spring, so the shutter travel is not impeded. To reassemble, and time the mirror, I removed the cam, fitted the gear plate, and then replaced the cam (after some experimentation). The picture below shows the cam, ready to be fitted.

[John Farrell]

The shiny bits, after scrubbing with window cleaner, and an old toothbrush - ready to be dried.



The top on - with a needle stopping the wind lever spring unwinding.


The wind lever is fitted over the needle.

The camera is now back together, but doesn't work correctly. As I suggested upthread, I have too large an overlap of the shutter blinds. I'm just going to treat this exercise as practice.

[camfiend]

Disappointing, but I admire the effort.. would love to have hands steady enough to to what you have done John
Thanks for sharing it with us

Bob

[Stephen]

Not having it in front of me, difficult to check, but I think you have attached the second blinds tapes to long or slack.
The check, put the camera on B and make sure the first blind does a correct run to the far side, adjust the tension springs till the action is crisp if needed.

On B position, the second blind should be in the parked position just visible outside the frame surround. If it is further across the frame, the tapes are too long, and not up to the edge, then too short. It should also not move if prodded with a small rod, it is under tension.

If about right, and B works, but you get capping, it is usually a slow first blind, the second accelerates and over takes the first.

First check again the tensioners, and slacken off the second blind a bit. If this does not cure it, then it's the length of the tapes that is wrong, or they are not the right type, and maybe too stretchy. It should be the second blinds tapes to check first, but also check the first tapes.

Stephen.

[Stephen]

I tried looking up the correct length of the tapes to no avail, when I replaced some years ago, I took the easy way and measured from a working example apart at the time for lubricating. One figure I do know is four and a half turns on the first blind tensioner from slack is about right, it may need another turn, but if it dos not run at that point, then the blind is binding or the whole tensioner need replacing. Using any more turns is risky, back off and check other things before trying again from slack.

The other reason for capping is the release trip for the second blind is orientated wrongly about the shaft, I have no pictures, again it could be compared to another working Zenit body, which after all do turn up cheap.

[Stephen]

Isaak Maizenberg's repair book does not cover the Zenit B, but does cover the details of the shutter in the earlier types, generally the same arrangements transferred to the cast body framework.

[John Farrell]

Thanks for the information, Stephen. I don't need the camera for photography, so I'm not going to work further on it.

[Just Plain Curt]

It takes a real craftsman to work on these. Something I'm not capable of so I applaud your efforts. I managed to strip down 6 or 8 Zenits and a couple old Prakticas but even then I lost most of the parts as I lost interest. Great cameras though.

[mikelock]

Hi John Farrell
I need a little help refitting the shutter rollers and ribbons on my Zenit 12 ex. I had to strip it own as shown in your pictures, to reglue 2 ribbons that had got entangle and then pulled away from the rollers.
The biggest problem is what needs retensioning an how to align everything and tension the winder and the roller that I had to remove. And what to shim and how.
The mechanics look identical to your Zenit.
Can you help please?
Mike Lock

[John Farrell]

Hi there Mike, and welcome to the forum. I haven't completed the rebuild of this Zenit, and I have a Zenit E in a similar condition. I need to make a jig to carry the rollers, and lock the shutter drums together, to allow accurate measurement of the shutter tapes. This is on my to do list. When I get this sorted, I will post here with instructions, probably in a new thread.