mooge
Well-known
Introduction
The Wollensak Alphax #3 is a "press" type leaf shutter - actuation via a lever or a cable release cocks and fires the shutter in one stroke.
This shutter is paired with the Wollensak-Dumont CRO 75mm f/1.9 Oscillo-Anastigmat lens. Speeds range from 1 - 1/100 seconds in geometric series (1,2,5,10,25,50,100) and from f/1.9 to f/16 in full stops.
Diagnosis
This shutter was repaired for water damage, which rusted the leaf shutter blades together. Now, two years later, the lens is hanging up partway open.
Disassembly
Begin by unscrewing the front and rear lens groups. The rear group is locked with a setscrew.
Remove the retaining ring holding the name plate of the shutter. There is one hole for a tool- I might have used a screwdriver on this hole, or some sort of friction tool.
Remove the name plate and the shutter speed cam ring underneath it.
Fig. 1: Alphax #3 shutter with Oscillo-Anastigmat front group removed
To inspect the shutter blades, we must remove the plate with the shutter mechanism on it. This requires the removal of most of the items on the plate. The slow speeds escapement and shutter actuating thing (A in Figure 2) do not need to be removed.
Fig. 2: Overview of Alphax shutter mechanism
There are four screws that hold the mechanism plate to the shutter body. Two are under levers, one is under the block which accepts a cable release, and one is a pin faced screw that also acts as a shaft for one of the levers (B in Figure 2). Now the mechanism plate can be removed.
Underneath the shutter blades and actuating ring can be seen. Remove the shutter blade cover by undoing the five screws.
Fig. 3: View with mechanism plate removed
Now the shutter blades are revealed. They overlap and the first blade is doubled with another blade on top.
Fig. 4: View with shutter blade cover removed
Note the position of the shutter actuating ring relative to the housing - obviously if it is not in the right orientation it will not line up with the mechanism plate (note that the shutter orientation changes between photos).
Fig. 5: View with shutter blades removed
Diagnosis
Though the rust from the water damage was removed in the previous repair, the corrosion has notched to one of the shutter blades, which is now binding against another blade.
Fig. 6: Corrosion damage to shutter blade
Repair
The shutter blade should be replaced. The material is 0.002" spring steel shim stock, and would not be hard to obtain (though making a new shutter blade would be a bad time); I don't have any on hand so I just bent the notched section out of the way so it wouldn't get caught. I also put the damaged shutter blade as the double blade (last in sequence).
Reassembly
Like disassembly but in reverse, with a few things to watch out for:
/ EJL / v.1 / Feb 2017
The Wollensak Alphax #3 is a "press" type leaf shutter - actuation via a lever or a cable release cocks and fires the shutter in one stroke.
This shutter is paired with the Wollensak-Dumont CRO 75mm f/1.9 Oscillo-Anastigmat lens. Speeds range from 1 - 1/100 seconds in geometric series (1,2,5,10,25,50,100) and from f/1.9 to f/16 in full stops.
Diagnosis
This shutter was repaired for water damage, which rusted the leaf shutter blades together. Now, two years later, the lens is hanging up partway open.
Disassembly
Begin by unscrewing the front and rear lens groups. The rear group is locked with a setscrew.
Remove the retaining ring holding the name plate of the shutter. There is one hole for a tool- I might have used a screwdriver on this hole, or some sort of friction tool.
Remove the name plate and the shutter speed cam ring underneath it.
Fig. 1: Alphax #3 shutter with Oscillo-Anastigmat front group removed
To inspect the shutter blades, we must remove the plate with the shutter mechanism on it. This requires the removal of most of the items on the plate. The slow speeds escapement and shutter actuating thing (A in Figure 2) do not need to be removed.
Fig. 2: Overview of Alphax shutter mechanism
There are four screws that hold the mechanism plate to the shutter body. Two are under levers, one is under the block which accepts a cable release, and one is a pin faced screw that also acts as a shaft for one of the levers (B in Figure 2). Now the mechanism plate can be removed.
Underneath the shutter blades and actuating ring can be seen. Remove the shutter blade cover by undoing the five screws.
Fig. 3: View with mechanism plate removed
Now the shutter blades are revealed. They overlap and the first blade is doubled with another blade on top.
Fig. 4: View with shutter blade cover removed
Note the position of the shutter actuating ring relative to the housing - obviously if it is not in the right orientation it will not line up with the mechanism plate (note that the shutter orientation changes between photos).
Fig. 5: View with shutter blades removed
Diagnosis
Though the rust from the water damage was removed in the previous repair, the corrosion has notched to one of the shutter blades, which is now binding against another blade.
Fig. 6: Corrosion damage to shutter blade
Repair
The shutter blade should be replaced. The material is 0.002" spring steel shim stock, and would not be hard to obtain (though making a new shutter blade would be a bad time); I don't have any on hand so I just bent the notched section out of the way so it wouldn't get caught. I also put the damaged shutter blade as the double blade (last in sequence).
Reassembly
Like disassembly but in reverse, with a few things to watch out for:
- Make sure shutter blades are in correct orientation (not flipped)
- Make sure shutter blade cover is in correct orientation (notch)
- Use the pin faced axle to locate the shutter mechanism plate to the shutter body, or else it may not fit.
/ EJL / v.1 / Feb 2017
02Pilot
Malcontent
Nice write-up. The Alphax is a very simple shutter and an excellent first candidate for anyone wanting to learn disassembly and repair.
If you wish to minimize the friction on the blades, rub some powdered graphite onto them with a cotton swab (I usually put a little Ronosol on the swab first, which holds the graphite and helps to ensure even coverage on the blades). It will also inhibit further corrosion.
If you wish to minimize the friction on the blades, rub some powdered graphite onto them with a cotton swab (I usually put a little Ronosol on the swab first, which holds the graphite and helps to ensure even coverage on the blades). It will also inhibit further corrosion.
Great work! I might actually have a lens shutter repair manual that covers the Wollensak (would have to check it for certain) but really, I don't think you need it, you've done pretty well as it is. 
Cheers,
Brett
Cheers,
Brett