Kodak ball bearing shutter problem

[Aristotle80]

I've done a lot of reading about Kodak's Diamatic ball bearing shutter type, the one with 1/25, 1/50, and 1/100 marked speeds plus T and B. I have two Kodak folders with that shutter, one of which works well, and one of which only fires on 1/25 and 1/100. 1/50 worked fine for a year or so, then without warning stopped firing completely. When i look at the exploded diagrams and web videos about that shutter, it seems so simple. I don't understand how it could stop working at the middle speed, yet continue to function at the slow and fast speeds. I'm trolling for ideas before I break down and take it apart. After all, it's still perfectly usable right now, so why risk it until I have to? I'm always careful to switch speeds when it is UNcocked, but you never know how it was used in the 50 years before it was mine. Anyway, I'm asking because it seems this particular shutter design is particularly easy to work on, and if someone is pretty sure they know what is wrong I might stop wondering or go ahead and fix it if it's an easy fix.

For a little background on my experience, I've fixed a stuck aperture on an Olympus Pen, the one with selenium meter. It all came together properly.

 

[summicron1]

those are pretty simple shutters, i can't think it makes a difference whether they are cocked when you change the speeds...I'd say open it up and have a look, might be a bit of grudoo in there gumming it up, or something.

 

[Mr_Flibble]

It usually is the collection of dirt or the drying out of what little grease was used in it.
Only on rare occasions it will be due to oxidation of the parts or breakage.

 

[shutterfinger]

http://www.cameraeccentric.com/html/info/repair_1.html page 30.

 

[Aristotle80]

Wow! Thanks Shutterfinger.

 

[thuggins]

I know it's an old thread, but I have a Tourist with the same problem. The shutter fires fine on T, B, 25 and 100, but not 50. 50 acts like T. The shutter opens and stays open till the shutter release is pressed again.

Does the OP (or anyone) have an update?

 

[shutterfinger]

The site with the vintage shutter manual folded but it can be found in the wayback machine.

 

[shutterfinger]

I have a #2C Autographic Brownie with a #1 Kodak ball Bearing shutter. It has been boxed for years and I decided to clean it.
Upon reassembly of the shutter I discovered that the tension on the return spring affects the 1/25 shutter speed, too much tension and 1/25 is fast, too little tension and the shutter blades do not close completely.
A few degrees of arc makes a big difference in operation. I have not tested the speeds on mine but plan to do so in the near future.