1930s Deardorff rear extension mechanism

[john wilton]

I am the lucky recipient of a new V8. I think it is 1930s...square cornered lensboard, no front swing; battlescarred. Has tripod base...may have been added later?

The only mechanical problem I can see is that the right-hand pinion gear of the rear extension drive is not engaging or missing...turning the drive knob, only the left side of the frame moves back...the right side has to be pulled out in step with the left by hand. I would think it should be driven out by gear action, especially since there is a rack on both sides. But this is not a big deal...in most ordinary use I won't need back extension and if I do I'll just help it out. Seller (nice guy) thought that was the way it always was. Any thoughts? How hhard to fix, if it needs fixing?

The lens board assembly frame was surrounded by dried out gaffer tape, performing no function that I could see other than preventing the secondary rise fall. I took it off and am working on getting the nasty white tape glue residue off by rubbing with lighter fluid. Some is coming off, some staying.

[CP Goerz]

I have had some Dorffs that didn't rack smoothly, this was usually caused by the teeth no engaging or only one side doing the work. I found the cause was usually the rear standard taking a hit at some point causing one side or the other to shift a couple of notches. The remedy is pretty simple, remove the small set screw at the end of the rear rail and then pull the rear standard off its rack completely. Then carefully engage both cogs at the same point, it'll take a few tries but one you have it on the back will be smooth as silk.

[Jim Galli]

If the drive gear has come loose from the axle it will do what you describe. See it you can move the gear independent from the axle. If so you may have to have it re-soldered to the axle.

[john wilton]

If I shine a flashlight from the rear into the narrow space above the baseboard and below the rear extension drive rack, I can clearly see the teeth of the pinion gear on the left, not so on the right. I don't sense that teeth are chewed up or not engaging properly or anything like that...the drive action is perfectly smooth. Is there somewhere for a pinion gear to migrate along the shaft to? Assuming it is there, how is it keyed to the drive shaft, and how would I get at it?

[Jim Galli]

I'm out of town today so I can't put my 'dorff in front of me but you can have the whole thing apart in minutes. They are elegantly simple. Sounds like perhaps the gear is missing?? Odder things could happen over a 75 year life span. Take it apart and find out. While it's apart clean each piece and give it some fresh lemon oil. I don't recall how the gear is attached to the axle. Silver solder? Brazed? Ken Hough would know and he might have the missing gear if it's gone. There's no place for it to migrate too iirc.

[john wilton]

Hi Jim,
Maybe these pix will help analyze my case....the only exposed drive shaft is the one under the back swing turntable...on mine the pinion gears are brazed/soldered onto the shaft, presumably the other two assemblies are similar.

On my camera the front extension drive knob is on the left, the rear two on the right. Without all three easily removable lock nuts being on the same side, this might make removing one at least of the side rails more difficult.

[john wilton]

Pix:

[Kevin Klazek]

John, I rebuilt a V8 about a year ago. The pictures you show look like someone made a repair to the pinion gear that moves the rear turntable forward. Factory soldering of the pinions to the rods is normally very neat and clean. If your rear extension is not moving back evenly and you have to pull one side, the pinion has come loose from the shaft. Mine had the same problem. The fix is to take it apart and silver solder the pinion back in place. You can't really see that pinion as it is buried under wood. There is no place for it to go or slide to.

As Jim said these cameras are very simple any easy to work on. To get to the pinion and remove the shaft there is a fair degree of disassembly. Just keep track of the parts and take pictures as you disassemble.

Good luck.

Kevin

[Jim Galli]

Forgot about this when home last weekend. I'll have a look at mine tomorrow. The gears shown drive the back carriage back and forth. That's different from the rear extension frame. Wow, that really is an oldie. Does it have a serial no?

[john wilton]

Jim, no serial number. Square lensboard, steel swing turntable...that makes it 1938-42 according to Ken's page? No serial number. I thought I found NO.1508 stamped on a side rail, but when I saw it was on both sides of the camera I realized I was looking at BOSTON upside down!

I partly removed the bottom rail. (The front extension drive shaft prevents complete removal without major camera disassembly, because the drive knob is fixed to the shaft on this side).

Sure enough the pinion is right there, rotating freely on the shaft. It would have to be brazed in situ I imagine. Not something I have ever done. Is it something I might contemplate doing? Can it be done with the shaft in the camera as in the pic?

When I first came to New York the city was littered with machine workshops. Gone to condos, every one. Or China. With the back/bellows/lensboard removed I could take the base to Martys Camera Repair in Queens...or perhaps an auto repair shop would be more appropriate?