Silly lens assembly generic question: factory markings to reassemble on correct thread start?

[jay moussy]

After reassembling a lens on correct thread start on frozen Isolette (and now facing the task to extract an Ektar 101mm off a bum shutter :-( ), I wonder if there were any factory markings helping with assembling lenses?

 

[gone]

None that I know of Jay (been there myself on the same camera). You're stuck with trying it in different places, and using a piece of GG on the film rails to know when it's correct. It's not so bad. Put some music on that you like, sit down w/ a cup of coffee, and put it together, being sure to mark each place where it didn't work.

 

[jay moussy]

Factory workers, later repair persons must have had some system, a set of marks?

@momus , my crude markings on the Isolette worked, but I cheated, left the focus ring on!
Now, I need to take apart an Ektar 101mm off a bum shutter, so I was hoping there would be a set of markings.

 

[John Koehrer]

Magic marker/sharpie/scribe mark before you take the thing apart
Front group focus are usually continuous thread so no problem. interrupted
threads................Mark or scribe.

Wonder how the did it in factories too.

 

[AgX]

Wonder how the did it in factories too.

They just used arbitrally any of the starts and then focused and set the distance scale and arrest to fit.

 

[albada]

They just used arbitrally any of the starts and then focused and set the distance scale and arrest to fit.

I carefully unscrew the helicoid, and I scratch marks on both pieces of at the point where they separate. Also, I count turns, so that I can get it back close to infinity. When it's back together and close to infinity, I locate the dents left in the helicoid from the set screws (grub screws) for the focus ring, letting me restore the exact adjustment when it left the factory.

 

[AgX]

But in the case it got disassembled before doing a marking, momus gave the good avise then to (temporarily) mark the start positions (or rather the get-loose positions) that did not work, until you find the right one.