Whats the post on the back of my 135mm Optar for?

[mattk]

I just bought a 135mm 4.7 Wollensak Optar for a Speed Graphic I am restoring and it has a small screw post that appears to the stop for the aperature adjustment lever. I took it out to mount it to lensboard--it doesn't appear to have any other function--can someone shed some light on the issue.

 

[Trevor Crone]

These were designed to stop the lens/shutter mount moving on the lens panel. A hole is drilled in the lens panel for the screw, so once tightened it would prevent movement especially when cocking the shutter.

 

[Nicholas Lindan]

These were designed to stop the lens/shutter mount moving on the lens panel.

External flash synchronizers - a solenoid activated by the flash that trips the shutter - were used with Speed Graphics 1920 - 1960.

If the lens rotated even an ooch the flash synchronization would be off.

The pin kept the lens from rotating in use. It also allowed swapping lenses on the same lensboard.

Solenoid flash synchronizers are useless with electronic flash, instead the lens shutter has to trip flash. It is common for a camera to have a synch solenoid for flash bulbs and an X-synch-only terminal on the lens.

The solenoid approach was used as it worked with all existing lenses when it was introduced. As the solenoid stayed with the body when the lenses were changed it was far more economical than adding synch to every lens.

Graphics also had a synch terminal on the rear focal plane shutter. The shutter curtains were so slow the same synchronizer could be used trigger either bulb or electronic flash.

More than you ever wanted to know ...

 

[mattk]

So I guess i won't have to try to find it in the carpet! I don't know why but I have this compulsion to take things apart before knowing what effects my actions will have. I was somewhat pleased by the fact that when I removed it, I did not hear a mysterious spring launch itself from inside the shutter. Thank you both for your response--this forum proves its value constantly for those of us just learning.

Matt