"lens board" for Certo Super Sports Dolly

[Romanko]

I recently bought a Certo Super Sports Dolly Model B in a decent condition. Unfortunately, it is missing the "lens board" (the part that holds the shutter/helicoid/lens assembly and is fixed to the front with a latch). This is the bright metal part with a serial number, see the picture that I found on the net. Any ideas on where to find or how to manufacture a replacement lens board?

 

[Ian Grant]

There's some photos on this page near the bottom, it appears not to be simple. The images are not particularly clear.

Ian

 

[xya]

That's my page, to which you both refer. I own about 10 Super Sport Dolly models, but not all of them are B models. I think it would be easier to buy a non working camera to get that part. It seems rather complicated to make. I could help with photos in case of, but I would prefer to do that in spring, my atelier has no central heating and it's cold at the moment...

 

[Romanko]

That's my page, to which you both refer

Sorry for stealing the image and thank you for your reply. The part seems complicated but a good machinist will have no problem making one. The most critical dimension is the height. I can probably determine it experimentally using shims but this is a slow process.

I could help with photos

That would be very helpful. Maybe you could bring the camera to a warmer place to take the photos?

 

[Dustin McAmera]

You don't have the plate, but you have a lens to go in the plate?

I have one of these, somewhere. The SS Dolly I use for preference is a rangefinder one, with a Tessar and unit focusing, but I have another one with the latch to remove the lens, and with a film/plate back. The plate for mine might be simpler, because it has a front-element focusing lens (it's a Trioplan) so there isn't the focusing scale right by the latch; but on the other hand, they may be exactly the same part. For now, this is the whole camera:

 

[xya]

That would be very helpful. Maybe you could bring the camera to a warmer place to take the photos?

I will be home next week and try to locate its box(es). There are more than 100 boxes on shelves. Yes, for the photos I will bring it into a warmer place.

 

[Dustin McAmera]

I went and found my camera.



This is the back of the lens/shutter unit with its mounting plate.
The plate is nickel-plated brass (I think nickel), and I measure it as 1.1mm thick.
It started life as a disc 59.0 mm diameter. It has two flats ground on the sides; the distance between those is 56.0 mm. The flat section is 18 mm high (that should be a redundant measurement).
As you see, the plate has a ring of felt glued on the back. The outer diameter of the felt is 48 mm.
The notch (seen here on the right: it's actually the bottom) is about 1.5 mm deep. You can see it's filed at an angle, and the edge of the plate is chamfered too.
Next slide please.

 

[Dustin McAmera]

This is the lens/shutter unit from the side: it's sitting on one of the flat edges.
You can see the plate itself is pressed out to make a central raised, flat section; or seen from the other direction, it creates a central depressed section, in which that felt ring (in the previous picture) sits.

I make the overall thickness from the rear of the plate to the front of the raised section 2.4 mm; but with what I have to hand (a Vernier caliper) I wouldn't want my life to depend on the exactness of that. It seems to me that my lens plate has deformed slightly, into a saddle-shape. The top and bottom edges lean slightly toward the back, and (I think) the sides lean forward. I toyed with the idea of tightening the plate in a vice while I had it apart, but I held off doing that, on the remote off-chance the shape is deliberate.

You can see two spacers behind the shutter unit - the thick black edges. These are aluminium, with inner diameter 30.9 mm and outer diameter 41.8 mm. They are 1.1 and 2.0 mm thick, but I guess that may be specific to my camera and lens. Next slide please.

 

[Dustin McAmera]

I unscrewed the retaining ring, and the plate comes off easily. They left a little bit of a burr in the centre: those Germans are so relaxed...
The diameter of the hole in the middle is 30.4 mm. I make the diameter of the threaded rear barrel of the lens 29.9 mm.
The diameter of the raised section is about 49.5 mm on this side; but it's defined by the other side, where it neatly accommodates the 48mm felt ring.

 

[Dustin McAmera]

This is the rear side of the plate, with the felt ring. You can see it sits about one mm clear of the central hole.

This was taken at a bit of an angle; those flats on the side are parallel.

 

[Dustin McAmera]

This is just the retaining ring. I only included a photo of it to draw attention to this, which is odd, I think: the ridge in the middle doesn't fit inside the hole of the plate. The thing depends on the felt to take up the depth of that ridge. Doesn't seem right to me, but that's how it is. Maybe not the original retaining ring?

 

[Dustin McAmera]

As I said, there are two aluminium spacers, and they are 1.1 and 2.0 mm thick. Their internal diameter is 30.9 mm and external 41.8 mm. So they are not tight on the rear lens barrel.

 

[Dustin McAmera]

That's the front standard of the camera, where the plate fits. You can see (can you? It's a bit small) at the bottom, there's a small lip of metal folded up, and a tiny screw passes through it front-to-back: that's what centres the notch in the lens-plate. The top of the plate is held by the hinged latch, just visible here. There's no locking feature on it. I have once detached the lens accidentally while I had film in the camera.

The other lever, below the front standard, adjusts the lens position for film or plates.
That's all folks. Hope these were helpful; let me know if you want anything else measured.

 

[Romanko]

You don't have the plate, but you have a lens to go in the plate?

Yes, the lens was mounted directly into the front standard to make the camera look complete in the photos.

@Dustin McAmera
Thanks a lot for the photos and the measurements. I came up with a somewhat similar design for the replacement plate but I completely overlooked the need to light-seal the assembly. This is what the felt is for.
It appears that the lens board is interchangeable between front-focusing and helicoid-focusing versions of the camera. My retaining ring is different. The aluminium spacers in your camera compensate for the thickness of the focusing mechanism.




I now have all the information required to manufacture the part. Thanks again.

 

[xya]

I now have all the information required to manufacture the part. Thanks again.

That sounds great. Good luck and please keep us updated of the outcome!

 

[Romanko]

Here is a drawing of the lens board. A few non-critical measurements (chamfers etc.) are omitted.