Home  1: Introduction and research  2: Basic parts and materials 
3: Initial test box  4: Framework mockup  5: Designing lens and aperture mount 
6: Designing camera back and film holder  7: Design tweaks  8: Film holder construction 
9: Camera back construction  10: Camera aperture failure  11: Camera aperture success 
12: Camera back framework  13: Camera shutter  14: Ground glass 
15: Camera front framework  16: Bellow test 

CHAPTER 8: FILM HOLDER CONSTRUCTION

Well well, now things are starting to happen for real! Iīm done with the film holder and it seems to work perfectly. The basic construction is pretty much exactly as I designed it with only a few small tweaks. To start with Iīve added a few extra support sections here and there, and then if you compare this real one with the design you can see that the knobs on the top look a bit different. I have two axles running straight thtough this peice between the film rolls and their purpose it to make it possible to fasten the bottom part. I manages to get these things fixed on the inside so there was no point having them going all the way up through the roof so to speak, and they wereīnt long ebough to do so either which at first struck me as a problem. But this solution looks better anyway. The spring lock mechanism on the left side for advancing the film turned out as planned and works perfectly, as well as the dial mechanism on the opposite side, I added a knob on top of that one as well, and if I want to really make sure the film is streched out flat I simply turn this counter clockwise to pull back any slack on the film, although I donīt expect there to be much slack in the end anyway. As you can see on the images below I have no feeder roll inserted, only the reciever. I realized a day ago that I need a empty extra roll all the time but I havenīt got one right now. I also surprized myself with how exact and tight I managed to get the rolls positioned. As noted earlier Iīm working with tolerances of about half a millimeter here on the more important parts and I think Iīve managed to come out clear in almost every case. Some small things may be a tiny bit off but that doesnt matter. Iīve been extrmly lucky in another way as well, the axles I use turned out to work really nive at their original lengts so I didnīt need to cut any of them up.

Film holder front.

Film holder back.

Film holder side.

I had to modify a few small parts for this construction due to flaws in my design. Initially I intended to use a small gear with all but two teeth cut off as the bit that hooks into the film roll, but this didnīt turn out as planned and I came up with another solution instead which ended up working better anyway. The plastic used in lego parts are really tough and stands up to alot of force before itīs bent or broken. The other thing I did was creating four small washes by splitting some small stoppers, these turned out really nice and solved another thing I realized I had overlooked. The vertical axle that turns the dial from the feeder roll had nothing to lock it down into itīs position from below, but one of these washers solved that perfectly. I used one of them on each end of the film roll which made them fit ridiculously good and perfectly centered to the film plane.

Modified parts.

Below you can see the top part whithout the top glued on where the mechanics was later added. You can see the tops pf the axles that runs straight through and locks the bottom peice on, as well as the small film guide rolls. The small box sticking down in an angle is a channel I made for the spring that pushes the lock peice onto the gear making it turn only in one direction. All the holes were kind of a bitch to make, I first used my hole punsh to make a hole which I then enlarged somewhat using my dremel tool to allow the axles to turn smoothly, and I had to make the holes before gluing the cardboard sheets together becuase the hole punsh wouldnīt be able to punsh holes through two sheets at the same time. As you can see the most sides and bits are made up from at least two sheets of cardboard, this makes everything very rigid, and if this thing will break anywhere it will not be in the glue seams thatīs for sure. The white carpenters glue really bites in the cardboard.

Film holder top anatomy.

Continue to chapter 9: Camera back construction

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