Heliar 420mm F4.5 Barrel Lens Disassemble

[diversey]

I have a Heliar 420mm lens. It has a lot haze inside. I can easily unscrew the rear element, but was unable to unscrew off the front element. I was wondering if the lens can be disassembled from the back after removing rear element where the iris is. Thanks
Picture one, front


Picture two, back

[Conrad . Marvin]

I’m not familiar with that lens, but usually it is necessary to remove the ring to get access to the front lens elements.
You probably will have to encourage that ring somehow. Try to hold it evenly without pinching and use some sort of rubberized cloth when unscrewing and maybe use some sort of strap wrench to get it started. Good luck!

[Steven Tribe]

No entrance through the rear!
See photos.
The front and middle lens are screwed together in one unit which is released by the thread of the “hood”.
Note my early 36cm has a much more substantial hood.
The Heliar “aluminium” is both very brittle and subject to locking corrosion in the threads!

[Greg]

For stuck aluminum threads Mouse Milk Oil works great.
Wrap a heating pad around the lens and warm it up a bit, NOT HOT, just warm the aluminum up a bit.
Use a little, just a few drops, and let it sit for a few days.
If it works, wash the threads with soapy water, rinse the threads in hot tap water, and then dry with paper towels before re-assembling

Just Google it

[diversey]

I could not unscrew the front element off by bare hands, definitely I need some tools like strap wrench. Thanks!

I’m not familiar with that lens, but usually it is necessary to remove the ring to get access to the front lens elements.
You probably will have to encourage that ring somehow. Try to hold it evenly without pinching and use some sort of rubberized cloth when unscrewing and maybe use some sort of strap wrench to get it started. Good luck!

[diversey]

I watched a youtube video about disassembling a 360mm Heliar front element, it seems easily to do. My 420mm is frozen, it is a Helier "aluminum" and no hood. Thanks for your pictures for references.

No entrance through the rear!
See photos.
The front and middle lens are screwed together in one unit which is released by the thread of the “hood”.
Note my early 36cm has a much more substantial hood.
The Heliar “aluminium” is both very brittle and subject to locking corrosion in the threads!

[diversey]

It is my first time to hear MOUSE MILK OIL. I googled and found it. I will follow your suggestions and give it a try. Thanks!

For stuck aluminum threads Mouse Milk Oil works great.
Wrap a heating pad around the lens and warm it up a bit, NOT HOT, just warm the aluminum up a bit.
Use a little, just a few drops, and let it sit for a few days.
If it works, wash the threads with soapy water, rinse the threads in hot tap water, and then dry with paper towels before re-assembling

Just Google it

[diversey]

https://www.largeformatphotography.i...ght=Hose+clamp

Followed the link above by using a 4-5 in diameter hose clamp, I successfully unscrewed the front element from my heliar lens and cleaned haze inside the lens. Thanks for all your information.

[Tin Can]

Wonderful!

[Jim Graves]

That had to make you smile! And what a nice looking lens.