fabricating wooden camera backs, reducing backs, expansion and enlarging backs

[Michael Roberts]

If you are into vintage wooden cameras, then you know they sometimes do not come with their original backs--e.g., missing back or 4x5 back on an 8x10, etc. It's also nice to have a reducing back to use on a 5x7 or 8x10, etc., so you don't have to rely on a second camera. Sometimes it's even fun to move up in format, and there are a few manufacturers who have supplied expansion backs as an accessory. Then there is the need to modify vintage backs to accept standard modern film holders instead of proprietary holders or plate holders....

So, this thread is to collect DIY work to construct missing wooden backs, modify backs, and fabricate reducing and expansion backs.

Here are a couple of related threads, and I will post more photos from backs I have made and modified in sizes from 4x5 to 12x20 over the next few days/weeks. I invite you to add your own project and photo descriptions....

Michael

7x11 original back modification and expansion back for 8x10 camera:
http://www.largeformatphotography.in...7x11+expansion

this thread has information about how to determine the added depth needed to add an enlarging back, e.g., 8x10 onto a full plate camera, or 11x14 added onto 8x10...see, especially, posts #17 and #20:
http://www.largeformatphotography.in...7x11+expansion

post #51 of this thread shows a 12x20 back I'm currently working on.
http://www.largeformatphotography.in...Kodak-2D/page6

I will post some sketches of the different layers I use when making a back from scratch. I know many forum members are much more accomplished woodworkers than I am. For most of the projects I've done, the only tools I've used are a metal ruler, an exacto knife, a craft wood saw, and a chop (mitre) saw. I've only recently acquired a small table saw and router.

Because of the limited tools I've had, I have mostly used pre-cut craft woods--balsa, basswood, cherry, and mahogany.

In building a back from scratch, I follow these steps:

1. determine the thickness of the base layer I want--usually 1/4 inch thick
2. determine the height and length, say for an 8x10 back, 11 and 1/2 square
3. determine the center opening dimensions--say 8x10
4. by elimination, determine the base frame, e.g., 11 and 1/2 minus 8 inches (or 10) and divide by two to determine the width of the base frame for each side, e.g., 1.75 inches on the 8" side and 3/4 inches on the long (10") side
5. since I know I can get craft wood 1/8" thick and in 1/4, 1/2, 3/4 and 1" wide strips, I'll design the base layer 1" x 11 and 1/2 at the top and bottom, and the two sides will be 3/4 x 9 and 1/2"
6. I'll fill in on the long side in the inside of the opening
7. for the second layer (on top of the base), I'll overlap the side pieces, so they are 11 and 1/2 long and 3/4' wide. This enables me to overlap each of the joints.
8. on the back side, I'll use 3/4 x 1/8" for the inside light trap. These are usually 1/4" shorter on each side, so, say 11"x11" on the outside. Gluing these down also strengthens the frame as it is being built up.
9. next comes the U-shaped "runners" the film holders will sit on and the U-shaped surrounds to hold the film holder in place, block light, and for securing the tension spring and gg frame. I usually use 1/2" x 1/2" basswood for the surround and 1" x 1/8" basswood for the runners.

photos and info on constructing a gg frame and making a gg with acrylic and window film covering to come....

[Joe Smigiel]

For awhile, I contemplated making a 5x7 to whole-plate pyramidal expansion back for my Deardorff 4x5 Special, but didn't get very far with it. I assume a pyramidal back could be made less deep and thus be somewhat lighter than a simple orthogonal box. The tradeoff would be increased difficulty in making the mitered cuts and then more difficulty gluing everything up. (Probably a good rationalization for picking up a compound miter saw soon.) Rather than making the pyramidal extension out of one central layer, I also considered stacking overlapping rectangular frames of ever-increasing size to build up the depth needed.

I eventually ended up finding a Rittreck 5x7 to whole-plate expansion back and will adapt that to the Deardorff, but I'd also like to try my hand at making such expansion backs for other formats. I can see an 11x14 to 14x17 in my future for the B&J Commercial View.

Realistically, I won't be able to get back to any of these project for months, but I'll be following this thread with great interest and hopefully adding useful info. I've also been playing around with Sketch-Up to make drawings in 3-D and have found that free program useful on a number of other projects.

[Tim Meisburger]

When I built my 8x10 back, I simply took off the 4x5 back off my Ikeda Anba and used that, and an 8x10 film holder, to get design and dimension. The only thing I did differently was to use a half lap rather than open mortice and tenon on the frame corners. Half lap worked fine at this size, and probably would at 4x5 as well. I have and used a table saw, and made and used a scratch stock to shape the curve on the wood in the holder throat. I used mohagany.

For reducing backs I have used a plywood field and simply attached a back of the appropriate size. I've used old Crown Graphic backs for 4x5 (super easy) and an old wooden back for 5x7.

[Lachlan 717]

The back for my DIY 7x17" camera.

I was actually surprised how easy this was to make. Good equipment makes a big difference, it seems.

[Michael Roberts]

Lachlan, do you have any in-process pics or a link to more? What kind of wood did you use? Did you fabricate the springs yourself or source them?

Looks great!

[Lachlan 717]

Here is a link to our local LF site, showing the build.

Thanks, Michael.

The springs are 'Dorff 8x10 that I bought second hand. The rest is home made.

Just got the bellows to build. I've found some rubberised block-out curtain material that I'll try, as well as importing som Lexan 0.010" for the ribs.

Timber is Australian Walnut.

[Tim Meisburger]

Here is a link to the description of the 8x10 back I made. http://www.largeformatphotography.in...-new-8x10-back

Lachlan, your's looks very nice!

[andreios]

Great topic, and comes very timely, I am awaiting the delivery of a half plate Vageeswari camera that will need a modern back - I have a spare cambo 5x7 back which will work for start, but I really want to make a wooden back...

One thing that I'd like to know is what material do you use (and where do you get it gfrom) for leaf springs...

[Tim Meisburger]

I bought my spring from deardorff, but if you have to make them the tried and true method is using hacksaw blades for material, as they are spring steel. If I would have used them I would have ground off the teeth and done any shaping with a bench grinder (you have to be patient and not overheat the metal as it will lose its temper and spring. It will just bend and stay that way.) Then remove th paint on the blade using either chemicals or sandpaper. Handsaw blades would work as well, but might be too thick and would be harder to shape.

If you have a metal shop nearby you can ask them if they have any suitable scrap spring steel.

[Lachlan 717]

Michael, try this:

http://forum.largeformatphotography.....php?f=6&t=547