A DIY 177mm f/8 Cooke triplet for 4x5 from off-the shelf lenses that YOU can build

[Nodda Duma]

Front side of aperture and lens #1 seat done

[Nodda Duma]

Mounting flange and back side O.D. mostly done.

Time to part it off to work on the back.

[Nodda Duma]

So I parted it off and made a plug to fit inside the hollowed out front, so when I chuck it up the barrel won't collapse (at worst) or warp (at best). So I've done that, and have runout the barrel in preparation to turn the rear lens seat and back of the aperture. That's for tomorrow.

[Peter De Smidt]

This is fun to follow. Thanks for posting!

[stawastawa]

That is a skinny little tab you have to hold the flint.
What is the tool to make the little groove just to the left of the flint? what is it's purpose? I don't see it in the picture so maybe it wasn't needed after all.

[Nodda Duma]

The skinny little tab the flint seats on is the aperture stop. I'll edge-bond the negative lens in. The positives will be face-bonded.

The little groove will be the slot where the waterhouse stops will go. I'll mill that when I'm done turning.

Drawing's not quite to scale. I'm no draftsman

[stawastawa]

ah water house stops! I was still thinking the aperture assembly was being used.
n

[Nodda Duma]

Yeah I figured waterhouse stops are a bit less ambitious for the first lathe / mill work I've done in several years.


Also ordered a thread turning tool. Gonna try machining internal helical light baffling (continuous thread on ID's between lenses) instead of just painting flat black.

[Ken Lee]

I have the feeling that this is the start of something really big.

Today, only a lathe. Tomorrow...

[Nodda Duma]

Done on the lathe