I posted my previous blog post on reddit, and got a lot of great feedback! As such, I want to make the cad files publicly available, alongside some instructions so that anyone who’s interested can build (and improve upon) my design.
Step 1 - Download the .dxf files
I’ve zipped them all together, here. Lay them out, and cut them out of 1/8th inch plywood or some other 1/8th inch thick material of your choice (perhaps opaque acrylic?). Note that the units in all the files zipped above are in centimeters. If you don’t have access to a laser cutter, get in touch with me via email and I can cut parts for you. You should cut a single version of each part in the archive except for the ‘front of lens box,’ of which you’ll need two.
When you’re finished, you should have 26 parts for the camera body, and 6 for the camera back.
Step 2 - Buy other parts and get ready to build
In addition to the laser cut items, you’ll need:
3/16 inch dowel
1 ~1.5 inch section
2 ~1 inch sections
½ inch dowel
1 ~3 inch section
3 large nylon washers (.505in inner diameter, 3/4 in outer diameter, 1/8 in thick)
1 small nylon washer (.171 in inner diameter, 3/8 in outer diameter, 1/4 in thick)
lens (I used a Fujinon 65mm f/5.6 SWD)
If you use a different lens, you’ll need to adjust the length of the lens box to your flange distance
¼-20 hex nut for tripod mount
2x 10-24 hex nuts
2x 10-24 socket cap bolts, 1 inch long
black yarn, black felt, black foam for light seals
I used the following tools and supplies:
sandpaper in various grits
Xacto knife with sharp blade
a couple of clamps
drill (potentially needed if your shutter won’t sit flat on the lensboard)
matte black spray paint
Step 3 - Assemble the rewind knob
Take your long section of 3/16 inch dowel and insert it into your small nylon washer – you may need to trim the end of the dowel a bit to fit. Epoxy it in place, then once hardened, using a craft knife or saw, carefully cut out a ~2mm x 2mm slot in the end of it, as depicted in the gif. This will interface with the film canister to rewind your film.
Step 4 - Cut and sand the film carrier
Take your matte plate - the film will need to slide smoothly across this, and it needs to be round and smooth to avoid scratching the film. Using a craft knife, shave a “slot” a bit wider than the width of a piece of 35mm film on either side of the piece. Once the slot is nice and rounded, sand it until smooth. I don’t have any photos of this process, but you can see the rounded section in the following picture.
Step 4 - Assemble the lens mount
Take your “lens box nut holder” and your two “front of lens box” pieces. The two “front of lens box” pieces will form a sandwich with the nut holder between them. Epoxy two 10-24 nuts into the nut holder, then wood-glue and clamp the sandwich together. Take your two shorter sections of 3/16 dowel, dab them in wood glue, and insert them into the holes that do not contain the nuts. These posts will support the lens and lens board. Again, I don’t have any pictures of this assembly before it was glued in place into the camera, but you can see it in its final position in the above picture.
Step 5 - Assemble the camera
Start by inserting the inner, outer, front walls, and matte plate into the bottom plate. Use a q-tip to apply some wood glue to the overlapping areas before assembly. Glue the top plate, get creative with the clamps, and let this dry. Important note: Most of the camera is pretty straightforward to assemble, like a big 3d puzzle. A lot of the pieces are mirror images of one another, so they can go in any way they fit. The one exception to this is the top plate, which has two holes on either side, one for the rewind knob, and one for the takeup spool. It is very important when you glue this in place that the smaller hole (for the rewind knob) goes on the left (when looking at the back of the camera) and the (larger) hole for the takeup reel goes on the right.
Once this has set somewhat, you can add the canister holder (to the left side) and the take-up reel holder) to the right. These pieces also need to go in the correct orientation, or they won’t be properly aligned. The narrower edge of the canister holder goes on the outside of the camera. The takeup reel holder is asymmetrical, the hole should be closer to the front of the camera. You can check the alignment of this by inserting your 1/2 inch dowel into the hole in the top plate, it should easily fit into the corresponding hole in the takeup reel holder.
In parallel, you can assemble the back, gluing the sides on to the back first, then carefully centering the inner door in place before gluing. You can also glue the lens board light seal ring to the back of the lens board, making sure it’s centered.
Next, add the “pinhole lens,” a naming holdover from an earlier version. Glue on the lens box, leaving the front lens mount assembly for later. Epoxy your 1/4-20 nut into the tripod mount, then using wood glue attach this to the bottom of the camera. Attach the top and bottom light seals to the back of the lens box, using your now-completed back to get the spacing right.
Take the rewind cap and rewind spacer, glue them to one another, then glue them to the top of the camera, taking care to make sure they’re aligned with the appropriate hole on the top plate.
Once the bulk of the structure is in place, add a few fillets of wood glue to all the inside corners, using a q-tip or similar. Let them dry a bit before re-applying. You can use a flashlight to check for areas that need more glue, but keep in mind that the camera won’t be completely light tight until after painting.
Step 6 - Paint
Mask the outside of the camera with masking tape and newspaper, then head to a well-ventilated area to apply a couple of coats of paint to the inside of the camera, the inside of the back, and the back side of the front of the lens box. Once this is done, you can glue the front of the lens box into the the lens box, potentially needing to sand the edges a bit for a good fit.
Step 7 - Add film take-up and rewind knobs.
Take the film rewind knob you assembled earlier, and insert it into the camera. It should turn freely.
Take your length of 1/2 inch dowel, and insert it into the hole in the top of the camera. Take two large nylon washers and thread them onto the bottom of the dowel, then insert it all the way into the camera. Slide one washer to the bottom of the dowel, so it butts up with the takeup reel holder. Glue it to the dowel, making sure not to accidentally also glue it to the camera; the dowel needs to spin easily. Next, glue some yarn around the top of the dowel to act as a light seal, then slide the upper washer up to press against the yarn and glue it here. Finally, glue a third washer to the top of the dowel, outside of the camera, sliding it all the way down the dowel so it butts against the top plate. Refer to the annotated photo for details.
Step 8 - Add Light Seals
Using scissors and a craft knife, cut some sheet foam to match the inverted shape of the “inner door” inside your camera’s back. Glue this in place, then glue some felt along the inside of the back’s walls where they overlap with the camera body. Run a “bead” of yarn along the front of the top of the box where it butts against the takeup and rewind knobs, and use more strips of foam and/or yarn to seal any other places that seem lacking. Run a ring of yarn along the outside of the light seal ring on the lens board.
Cut a few rectangles of foam and glue them to the inside of the back, to form a “pressure plate.” With the lens off, you may want to sacrifice a roll of film, load it into the camera, and then look through the lens hole to make sure the film lies flat, adjusting the height of the pressure plate if need be.
Step 9 - Finishing touches
Mount your lens in the lens board, and bolt it to the lens mount. Take a piece of wax paper and tape it to the back of the matte plate where the film will sit. Open the shutter of your lens, and check the focus. If needed, add some small spacers (construction paper or similar) to adjust the focus.
Take a Sharpie, and make two matching ticks on the take-up knob and camera back – you can use these to count revolutions as you wind the film.
Step 10 - Load film, and test!
Insert your film into the camera, and lock it in place by sliding the rewind knob down into the canister. Pull the leader out of the canister, and with a small piece of masking tape, tape it to the takeup spool, using care to make sure the film is parallel to the matte plate, and not crooked. Place the back on the camera, and optionally tape it loosely in place. Make sure the shutter is closed, then wind the takeup knob 3 revolutions. As you wind, make sure the rewind knob also turns - if it doesn’t, something isn’t working! You are now ready to take your first picture! Once exposed, 2 full revolutions of the takeup knob will bring the next frame into position. As you shoot more and more of the roll, you should be able to wind a bit less than 2 times, as the diameter of the takeup spool has increased with film wrapped around it. With some experimentation, you should be able to get 12+ frames out of a 24 exposure roll, and 16 or so from a 36 exposure roll.
These instructions were written hurriedly, and I’m sure are confusing and contain typos. As always, please reach out with questions, suggestions, or just to say hi. If you do end up building something based off of these designs, please let me know – I’d love to see what you come up with!