Haze in 1938 13.5cm Hektor: lenshead disassembly?

[johnphoto]

I have a prewar uncoated 13.5 Hektor with slight haze. Has anyone taken the lenshead apart for cleaning? It looks as though the front optical unit housing the front element should just screw out, but gripping the front most part with rubber I can't budge it. There is a biggish grubscrew on the side of the non-turning ring (with aperture marks, Ernst Leitz and serial etc) that is in front of the turning aperture-setting ring.

* Would loosening this screw permit unscrewing the front optical unit (presumably a single element)?

* How does the rear unit come away from the lenshead barrel?

 

[charjohncarter]

My Hektor 135mm f4.5 I think is post war, but you can look it up to see if it is similar to yours. It dosen't sound like it. The only external screws (in the lens piece) are the ones holding the aperture ring. The lens on mine just unscrews, so maybe on yours they did have some kind of stop screw.

 

[davidnewtonguitars]

If you wipe a little Ronsonol, lighter fluid, naptha in the threaded parts, it will go a long way to loosen joints.

 

[martinjames]

Here's an earlier discussion regarding cleaning a 135 Hektor:

https://www.rangefinderforum.com/forums/showthread.php?t=81698

Looks like he went in by removing the rear lens element.

 

[johnphoto]

Thanks for the pointers. My lens is older than the ones mentioned, and has a different construction. It seems that the screw marked with a yellow arrow MIGHT be a grub screw holding the front optical unit from unscrewing, what else could it be. But does anyone know for sure what the screw does? I don't want the iris to unravel.

 

[charjohncarter]

That is more than a little difference than my early 50s version. But it seems like a strange place for a set screw. But what do I know.

 

[Dralowid]

Can't properly remember but that screw 'might' be the stop screw for the aperture ring. I'd leave it for now. I doubt it locks the front element in place. Reckon that "just" unscrews...well it may have done a lot of years ago.

Unscrew the head from the focussing barrel first then you should be able to remove rear element(s?) and things will become a little clearer.

 

[johnphoto]

Yes that screw is probably aperture related. I found instructions in Tomosy: The front optics will be very tight, but it just unscrews. Knowing this I applied the necessary torque. No more haze!