360mm f4.5 Schneider Xenar to Sinar board, part 1

Had this lens for a while, decided to mount it onto a Sinar lens board. eBay purchase, appears to have been used in a industrial or military application as the lens came with an unusual collar and mount with a long tube extension. That part got cut down to a 0.90" collar to raise the flange of the Xenar high enough to clear the aperture pin on the Sinar shutter. Once that was done, the process of cutting a 4.402" hole in the Sinar board. This began with setting up the Sinar board in the lathe with a four jaw chuck, small boring bar.
Attachment 206652

Hole roughed out.
Attachment 206653

Finish bore the hole to 4.402" with a BIG solid carbide insert boring bar.
Attachment 206654


Bernice

Sinar lens board hole bored to 4.402". Set up the 360mm Xenar lens collar in a rotary table, fit the lens board to the collar getting it ready to drill and tap four #4-40 into the collar and #4 clearance holes (0.130") into the lens board with countersinks.

Set up the lens collar and lens board:
Attachment 206669

Drill for# 4-40 tap four places, 90 degrees apart, do not remember what the screw circle dimension was.
Attachment 206670

Remove the lens board, tap all four holes to# 4-40.
Attachment 206671

Drill# 4-40 clearance holes and countersink them.
Attachment 206672


Bernice

Assembled the 360mm f4.5 Xenar lens collar with flange to the Sinar Lens board. The bare aluminum areas are darkened with a black sharpiee marker.
Attachment 206673


What the finished 360mm f4.5 Xenar looks like mounted to the Sinar Lens board on a Sinar P2.
Attachment 206675


~Why the Portrait oriented images upload and become landscape, no idea.. This is an admin question-problem.~

Bernice

Very nice work Bernice!

I've often thought a 4 jaw chuck with top jaws would be a useful thing to have. It would open up the possibility making custom top jaws for holding odd shaped work pieces. Probably easier than setting up on a faceplate.

Guessing that's an 8 inch chuck based on the size of the (Sinar) lens board. Is that right?

David

Yes, that is a eight inch four jaw chuck. Four jaw independent chucks are often better than a three jaw as it can be adjusted accuracy requirements of a part to be worked on. They can hold irregular shapes and have much higher holding power than a three jaw.

Example of what is involved to have a machinist or similar shop mount a BIG lens on to a board, it is machinery, tooling skill-labor intensive to do this properly.
Precision and accuracy of how a lens is mounted can affect the optical performance of a lens.


Bernice

Quote:

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Originally Posted by David Lindquist

Very nice work Bernice!

I've often thought a 4 jaw chuck with top jaws would be a useful thing to have. It would open up the possibility making custom top jaws for holding odd shaped work pieces. Probably easier than setting up on a faceplate.

Guessing that's an 8 inch chuck based on the size of the (Sinar) lens board. Is that right?

David

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Beautiful work Bernice :)

I have had some of my Norma lenses forward mounted in various ways.

Photo machining mounts can be expensive. I'd love some day to get a lathe and vertical mill.

https://live.staticflickr.com/65535/...6e853c9f_z.jpg300mm F4.5 Xenar Norma by Nokton48, on Flickr

This is my Norma mounted 300mm f4.5 barrel Xenar. A clockmaker friend cut down an enlarging cone of some sort. and metal epoxied it to a Norma board. Then cut down the flange making it into a thin-mount retaining ring, which just fits inside the cone.

This lens is great for 5x7 portraiture, I would like to find the 360 Xenar and the 420 Xenar. The ones I have seen have cost the moon.

Schneider Xenar from this era is one of the lesser know really good Tessar lenses. There was a time when Xenars were considered undesirable due to the Xenar being a lower contrast, optimized for larger apertures like f8 which was not what the commercial ad marketing images from the 1980-90's were mostly about. Regardless, they remained preferred and desirable by folks doing portraits and such.

This 360mm Xenar joins the 210mm, 300mm (head-shoulder on 5x7 lens) and the 480mm which was purchased decades ago when few if any wanted a lens like this. It was once used for 8x10 and not used much at all these days.
Attachment 206778

Using these barrel lenses is easy due to the Sinar Shutter and the Sinar system.


The Tessar formula continued on with GOOD examples made by Fuji, Komura and others.


Bernice