Using 4x5 film holders in a pack camera

Converting a pack camera to 4x5

First, download and 3d print the back, battery compartment, film holder/pressure plates, and the 18mm spacers for the lens body. Remove the hinge assembly off of the pack camera by drilling out the 4 rivets. The back, battery door, and the hinge assembly is removed. Don't throw it away, as you may want to replace it, or use it as a back for the Polaroid sized film holders, or other backs such as the 6x6 and 6x9 backs.

Step 1: First, drill two holes which align with the rivet holes that you drilled out to remove the hinge assembly. You should mark them precisely and low enough so the back mounts firmly to the camera.
Step 2: Next, find a couple of small screws and tap them into the camera. I found they self tapped easily by screwing in 1/4 turn, then unscrewing, then screwing back in another 1/4 turn until it's through.
Step 3: Put the back into place, latching the hooks and checking the fit, then screw the back into the camera. You will need to self tap the screws into the back by the 1/4 turn, back off method. Be sure the back gets screwed in to, and the screws don't just press against the holes.
Step 4: Line the edges where the film holder will contact the back with black felt. I just used white glue.
Step 5: Make an elastic strap with the included hooks and cut a couple of notches in the back to allow the strap to hold down the film holder while in place.
Step 6: Move the lens body back with the 3d printed spacers. This involves removing the top and bottom bolts off of the vertical strut, removing the strut, and the screw on the bottom left of the lens body, then installing the spacers and inserting a 3/16" rod through the lens body and back end of the spacers.

The camera is now ready to use a custom 4x5 film holder. You will need to prepare the film holder by cutting a 38mm wide piece of black felt and gluing it to the entrance (possibly shimmed a bit to give extra pressure), then cutting two dark slides out of bristle board, inserting them, then taping or gluing down the pressure plates.

To use, load the film into the film holder, strap it in the back, cock the shutter, then pull out the dark slide, but not all the way. Take the picture and reinsert the dark slide.