Ok, I have been putting this off … every year I tell myself that I should just do it … well, time to document replacing the shutter curtains on the Minolta-35 rangefinder. A decade ago one of the camera’s that started this blog was the Minolta Minolta-35 rangefinder camera.
As I mentioned long ago, one the biggest issues with the Minolta-35 rangefinder cameras is the shutter. Most cameras that you will encounter will have a non-working shutter, or that the shutter leaks like a sieve … and this is due to the compound that was used to coat the cloth. It wasn’t made to last, so many Minolta-35’s on the market will require a shutter curtain replacement sooner than later even though they might be listed as “working”.
Preparation goes a long way when dealing with this type of fix … so first look at Nobby Sparrow video and see how he is dealing with a Leica shutter replacement (don’t take specifics as the Minolta shutter is different). Then you can look at Michael Crawshaw video , he talks about his experience with the Minolta-35.
Then go back in time to my early posts about servicing this camera … some have replaced the shutter without taking out the innards, but I have found it easier to have more access.
Tools:
- Glue
- shutter material
- ribbon tape material
- curtain lath, just reuse the old ones
- painters tape
- etc … etc … etc.
If you happen to have the shutter still in the camera take note on the position of the metal lath (Note: prior to this replacement post I replaced the curtains on the second Minolta that I picked up … so this may not be the correct position … I will explain later).
In Michael’s video did not take the insides out to replace the curtains. I decided to take the insides out to give a good cleaning, and also make the shutter replacement a little easier do to … you can look at Minolta-35 – the shutter and speed gears for the disassembly notes.
Ok, so back to the shutter curtains …. measurements.
I have a couple of Minolta-35 model II’s with the curtains still attached when I bought them … taking them out left a lot of crumbled bits of old rubber. One of them “looked” OK, but using a light I can see many pinholes.
The width of the curtains is 32.3mm. Unlike a Leica rangefinder, this curtain does not use a lath with the tape attached to the outer ends … the Minolta shutter curtain has a U shaped lath the same width as the curtain and the tape is directly attached to the curtain going through slits cuts at the ends of the lath.
I measured the degraded curtains that I yanked out of the two cameras that I have. The first curtain is 64mm + 61mm tape … the second curtain is 84mm + 79mm tape.
The metal lath that forms the front straight edge of the curtain is a 0.4mm thick folded aluminum. Half of the camera’s that I have encountered have lath’s that use three rivet to secure it and the tape to the curtain … the others just had the lath glued on.
Ok, lets goooooooo …. now I will have to warn you I did not take pictures during this part … things that I will described have already been shown in previous posts …
Drill out the rivets with your handy 0.5mm drill bit. Clean out the old bits of curtain from inside the lath with a very thin blade … this should also open them up a bit.
The rollers are only 33.75mm wide , so we want to keep the curtain shorter than that. We will cut a length of 150mm curtain. The curtain material I got from Aki-Asahi is silk with one side rubber coated. I found that cutting with silk on top made a cleaner cut.
Next cut the tape. Depending on how much you want attached to the curtain, add +5-7mm.
I glued the tape to the silk side of the curtains … there seems to be no consensus to which side better. Let sit until the glue cures. Add some glue to the inside of the lath, though not the easiest thing, then slip it onto the curtain … give the laths a crimp to close onto the curtain.
Sooo, examining how the old shutter curtain wraps around the black rollers, I can see that a lot of material is attached … these rollers are thin so the curtains need more grip to stay on … looks like 16-19mm of curtain is glued, so it will have a full wrap … hmm, makes for difficult gluing in a confined space … or you make the curtains shorter, which will reduce the amount of curtain secured to the roller … hmm.
As I already took apart the top before I know that the second curtain roller is easily removable, and the first curtain can be pulled away from engaging the other gears … so this means I can start gluing to get a full wrap, then set the rollers back into proper position.
The inside rollers hold the first curtain … curtain is attached to the left side the spring roller, this is an easy glue. From the bottom, turn the screw/nut to wind up the spring so that the curtain gets pulled over. Make sure the lath is straight.
Glue the tape to the inside spring roller. Makes sure they both pull straight … no one likes a crooked lath.
Then feed the second curtain over the thin roller and through the black rail guides. The front edge of the second curtain should be 3mm past from the edge of the first curtain edge. In my case the lath is 2.6mm wide, so I need to place it just past the back edge of the first curtain lath.
Glue it to the right-most black roller.
The tape goes over the thin roller and glued onto the far spring roller … wind up the spring and check that both tapes pull straight.
Let it dry.
Ok, so now …. ehhhh … set all the gears in a shutter released position. The first curtain lath should sit on or just before the last bottom screw hole (this appears to align with just getting past the film plane opening), and the second lath curtain sits on top of it. Lightly wind up the black rollers to take up material … then put the top plate back on.
Easier said than done.
Now for adjustments, cause putting the top plate back on just throws of the gears … put in one plate screw on the front. Now you have some play to pull out the first curtain roller to reposition the gears. When that is ok, put the left screw on the plate and loosen the first one … then you can adjust the second curtain roller gear without disturbing the other roller.
Secure the top plate. Add some spring to the roller springs … Rick Oleson says 9 turns of the first curtain and 7 on the second … and see if the shutter is moving correctly. Wind up the shutter … you should not have any gap between the lath to let light through.
Now you can play with the spring rollers to get them travelling at the correct rate, start with 1/35s … then check the speeds of the others. The slow speeds from 1/25s are controlled by the slow speed dial … unscrew the cap and loosen the grub screws … turn the inside screw to adjust speed.
This Old Camera 