Making the guides is a multi-step process that starts
with the two guides still in one piece.
First, using the table saw a majority of the rabbit is removed. Here the outer passes have already been
made. Before the next pass the fence
gets moved closer to the blade and two passes removes more material repeating
until the cuts meet in the center.
Once that’s done, I move to the router. It’s used to flatten the ridges left by the
table saw, cut deeper and trim the sides to a sharp corner until the final
width and depth is reached. Below shows
the first pass at the top of the piece flattening the bottom.
To keep my fingers away from the router bit an adjustable
push block is used to safely push the piece thru. I only have 10 fingers and nearly cut my
thumb off once on the table saw. I
really, really don’t want to go through that again.
Once the final width and depth is reached it’s back to
the table saw to cut the blank into the two guides. The center of the piece is set on the center
of the blade and then cut. Once again, I
get a little help for safety’s sake.
The shutter piece gets rabbits cut just a hair deeper
than the ones on the guides using the router then the previously ripped guide
edges are run through the thickness sander until they match the ones on the
shutter. Here is how the guides and
shutter look after the fitting.
Marking the shutter piece for machining is next. There are several holes either all the way
through or part way through that need to be laid out. Below is the front and back layout plus the
punch I will use to mark the center points and the three different drills used.
Once the hole locations were double checked I could start
drilling. Here the top photo shows the
closed shutter with the guides clamped in place. The bottom photo shows the shutter slid over
and open. Neither the guides nor the
shutter have been cut to length yet.
If you look carefully you can see where there is a slight
arc cut into the top guide. That’s to
provide clearance so the pinhole assembly can be removed if it gets damaged or
for some other reason needs to be changed.
I had two options to allow for removal of the pinhole assembly. This way and screwing the guides on from the
inside of the camera so they could be taken off. I did not go the screw route because the
guides aren’t very wide and I was concerned that they might split when the
screws were installed. Also, if you look
to the left of the pinhole you can see the hole where the magnet will go to
lock the shutter either open or closed.
There are a couple of matching holes on the back of the shutter for the
mating magnets.
Drilling the thumb holds in the shutter is next. At this time, I will only be drilling the
right one. The left one will get drilled
later after the guides are installed.
The goal is that when the shutter is open the left side will be even
with the edge of the camera body. That
makes an easy tactile way to double check that the opening in the shutter is
aligned with the pinhole. The top photo
shows the setup and the bottom is a closer look after the hole has been
drilled.
Gluing the front onto the body and the axles into the
knobs then clamping things together are shown below.
While the glue cures on those pieces the channel can be
cut in the film box. That’s done on the
router, here is the setup. There are a
few things to point out with the setup.
First, the cam clamp is used for safety so I can get my fingers a little
farther from the router bit. Second, as
you can see the cam clamp is set on a piece of ¼” plywood. This holds the clamp above the table so I
don’t route a channel in it too. Last is
something that you can’t see. When the
cam is tightened down the clamp twists just a little bit so when the bar jaws
are flat on the plywood one side of the film box is up off the router
table. It’s such a small amount I did
not notice it until checking the depth of cut with a digital caliper. From one side to the other there was about 15
thousandths of an inch. Like I said not
a lot but, this is what the film will ride on when taking the photo and I want
it right on. The fix is pretty
simple. I just made sure the film box
was flat on the router table by pressing down on the high side of the clamp.
Taking off the clamp you can see the router bit and the
channel. It’s not very deep only about
four hundredths of an inch but deep enough to guide and hold the film in place.
After routing there are sharp edges on the leading and
trailing edge of the channel. Since the
film will ride on these edges they need to be softened. That’s done with some fine sandpaper. When done this is what it looks like. I still have to do the final sanding on the
film box but other than that it’s ready to be installed in the camera body.
Back in Post # 6 I mentioned that I might make a second
film box for a wider negative. Well,
here it is along with the first one. The
first one, on the left gives a standard 35 mm wide negative while the one on
the right gives a 48 mm one.
By now the glue holding the axles in the knobs is cured
enough I can epoxy the steel washers into their recessed spaces on the
underneath side of the knob. But first I
need to make a little caul to apply pressure to the washer around the
axle. It’s simply a small piece of
plywood with a hole drilled in it and in my case the easiest way to drill the
hole is with the lathe.
Once drilled the piece gets cut in half, epoxy is applied
in the recess and the washer set in place.
The caul is set over the axle and the assembly clamped. As the caul is longer than the axle all the
pressure is applied to the washer spreading the epoxy out and making sure there
is good contact.
This is what the knobs look like completed and ready for
finishing.
Next Up – Installing Film Boxes & Rounding Camera
Body Edges
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