1g. Cut both bolt ends so each protrudes 1" beyond the nut face. Get
an empty 120mm film spool from a
friendly camera lab, or untape one
from a cheap, expired roll of 120mm
film; this will be our take-up spool. File
the ends of each bolt flat on 2 sides,
so that they engage the slot of the
1h. Use thread-locking compound or mash the bolt’s threads slightly to keep the nuts in place, so that the
bolt assembly spins easily through the wood without loosening or tightening.
1i. Calculate the inside height of the camera by measuring the spool height and adding twice the height of
the nut stacks; using this dimension will center the film vertically. Cut a scrap block of wood down to this
1j. Calculate the outside height by
adding 1" (twice the plywood thickness) to the inside height, and cut
2 side rails to this length from the
½"×¾" wood. Clamp the top and bottom pieces around the scrap block,
and glue on the side rails after making sure that all 4 pieces fit together
evenly and are perfectly square.
1k. After the glue has set, cut a 1"× 5" strip of springy steel —
I used the sidewall of a tuna-fish can. Drill 1" holes that exactly
match the spacing of the bolts on the top, and then attach pop
rivets through these holes. The rivet nubs will catch the bottoms
of the film spools.
1l. Cut a small wooden block the
same thickness as the nut stacks,
and staple or tack the spring to it,
centered. My block was 2"× 1"× 1½".
Apply glue to the block and position
it on the floor of the camera. Load the
film and take-up spools between the
spring nubs and the bolts, and slide
the spring block around until the film
spools are exactly vertical. Clamp, and
let the glue set.