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5×7 part 3, assembly day(s)

Finished camera.  Looks a dumpster date between a Ebony and a Chamonix. Visually I don’t much like the predominance of aluminum, but it works like a dream. I may get the aluminum parts anodized black at some point to tone down the appearance a bit.

November 3rd

Parts, oh man. It would appear that I am close to finishing. But it will probably will take another 12 36 hours to get everything put together. I’m starting to remember that putting everything together and tweaking it to make sure it all works smoothly is roughly half the project.

Really glad I sprayed the finish last weekend. Woke up to 1/2″ of snow this morning. 29° in the shop.

Bellows frame rails. Clamps help keep the frame parts tight to the back during installation.  1/2″ x 1/2″ Aluminum angle wrap around three side of the interior, with a piece of aluminum channel at the bottom. The channel engages the frame, which is then tilted into place and secured with thumb screws. To allow the frame to be tilted in and out of the channel for easy removal, the bottom edge of the bellows frame is beveled slightly, and the channel has a length of .063″ spring wire set against the bottom front inside surface to wedge the bellows frame in place. The aluminum frame parts are painted black and each part is covered with velvet where it abuts the back. The bellows frame itself is rabbeted to inset into the aluminum frame, to add another level of light blocking.

 

Bellows attachment screws. An 8/32 threaded insert is installed in the standard. The last 3/8″ of the thumb screw is filed down to a 1/8″ pin, which engages with a hole drilled into the bellows frame, locking it in place.

My micro mill crapped out during work today, took half the day to track down a wire short in the fault relay. Will pick this up again in the morning.

November 11

Didn’t get much done last weekend. After spending several minutes Saturday morning looking for a screw that was stuck to my palm I realized it was too fucking cold to get anything done.

Got a bit done today, a balmy 36° in the shop.

Tripod plate. Sort of overkill, but I may make a 5×12 conversion back for this camera at some point. In fact I used  an 1/4″ aluminum plate from my old 5×12, then milled .75″ off the perimeter down to 1/8″ thick to reduce weight a little. I cut a matching recess into the bed, leaving enough at full thickness for a single 3/16-18 thread in the center flanked by two 1/4-20 threads. I used post screws to attach it to the bed for a more positive connection, plus some wood screws around the plate perimeter.

 

Plenty of rise and fall. The front standard is about done, just need to cut the rise locking threads to length, the install the bellows and lens board hardware.

Rise detail. A knob standoff plate allows the tilt to tighten down while still allowing rise and fall to slide easily.

Routed the groove for the light trap material, then painted the film holder area of the back black. Using 1/8″ EPDM gasket for the light trap seal. I got a few samples of the different foam seals from McMaster-Carr last year when repairing the Arca Swiss, and this one seemed to have the best combination of compressability, rebound, slipperiness , etc. The adhesive is very sticky it’s a little tricky to install, you have to be careful not to stretch it when installing or it will reduce in thickness, so I sort of roll it into the groove from behind instead of pulling it, only removing a little of the adhesive backing at a time.

Back attachment detail. Using pins with spring clips on the top and seats on the bottom. The springs are made from .015″ feeler gauge stock, the seats were milled from 1/2″ aluminum bar stock, and the pins were cut from 1/8″ stainless steel rod. The seats have an angle milled into the mating face, to allow the back to tilt in and out for removal. To drill the back, I installed the seats first, using the holes in them as guide bushings to drill the holes on all 4 sides. This way the back can be rotated 360° without losing registration. The spring clips on top were installed last. The pins are only proud of the back about 1/16″;  not much force is needed to flex the springs for removal but there’s enough to keep the back securely attached.

Attaching the bellows to the frames. The double stick tape worked really well, clean and easy. The trickiest part was making sure there were no voids in the adhesive around the perimeter of the bellows before attaching them to the frames. Only peeling back the backing from the corners allows for easy positioning.

November 17th

Shift and swing detail. I used a Delrin dovetail key for the shift instead of milling the pin and rear standard base out of one piece of aluminum. This allowed the part to be cut to much closer tolerances without binding and galling (I don’t like aluminum-on-aluminum bearing surfaces). The turntable platform and Delrin are longer than the standard base, which allows zeroing out shift by feel. Swing and shift are both controlled by the 1/4-20  knobs; the shift slot was cut in the lower platform, and the radial slots for swing were cut in the top platform.

The black riser blocks were made out of Cherry at first, sized with glue for durability and painted black- Mahogany was a little too soft for this. I’ve since remade them out of Delrin and chamfered all the edges. I used a router bit to true up the stock in the micro mill, it’s not at all square from the supplier. The bit was under-sized for surfacing in one pass, so it left a toolpath finish, but I sort of like it. Delrin cleans up nicely with a single cut file and a buffing wheel. The rear standard is inset 1/2″ from the back of the rear extension, this allows the standards to get closer together for wide angle shots with some extension bypass, and reduces the overall width of the camera as well for a better fit in the backpack.

Under the shift platform. The pivot bearing and shift/swing screw ride in one long slot. The slot is stepped on each end for T-nuts to keep them from spinning.

Done at last

Lots of fussy small parts left to make. Other than the tripod mounting plate I didn’t scavenge any parts from old cameras.  Ground glass clips, bellows clips, lens board clips, all these tiny parts seem to be the most time consuming, especially the stainless steel ones like ground glass clips.

For the ground glass clips I used some .031″ SS feeler gauge stock leftover from the bail back project, stuck a 10-32 washer to the stock with double stick tape, and filed it down to shape and size. The washer has a 5/8″ diameter, which is a common forstner bit size- due to the thickness of the GG frame relative to the ground glass, the clip has to be countersunk 1/4″.

The front bellows attach with sliding clips on top and a full length clip on the bottom. The slots are angled 10 degrees to provide a wedging action, and sized to take a #2 nylon flanged washer. I attached a small grip to each as well as the lensboard clip, made from 6-32 threaded spacers and screwed to the clips from beneath. Each of the clips is covered with UHMW film to protect the surfaces underneath. The bottom bellows frame clip is flared slightly to allow the bellows frame to be tilted in and out for easy removal.

Also, earlier in the week I realized that I’d screwed up on the front standard. I’d sized it based on a lens board from the other 5×7- except that the lens board I grabbed to use for a pattern was a reject that was slightly smaller than the others. So I had to widen the opening of the camera’s lens board stage slightly on the mill. Since the mill bit left a 3/16″ radius in the corners, I made some new lens boards to match out of  .25″ Baltic birch plywood, and rounded the corners of all the existing boards to match as well. While I was at it, I painted the freshly milled surfaces of the lens board stage flat black and lined both sides with velvet.

Boring lens boards. I made a centering jig that also holds down the board (the battens are rabbeted to fit the light trap). Especially useful for the ever-terrifying adjustable boring bit- I don’t even want to be in the same room as this thing when it’s spinning. Once the jig is positioned it’s centered for the remaining boards. I start on the back side to drill the oversized stepped hole for the retaining ring/ light trap, then flip the board and set it on top of the battens to finish the hole with a smaller forstner bit.

So after this final flurry of activity it’s actually done. Just checked it for light leaks.

This camera turned out better than I dared hope.  It’s really a lot of fun to use. All the movements are smooth and intuitive, they lock down securely and zero out by feel- which I vastly prefer to detents. Nothing feels like a compromise in use. The base tilt on both standards is great, very strong locked down, and doesn’t flop around when loose- there’s enough friction in the bearing to hold the position in place until you lock it down. Once locked down they don’t budge, no slop, no wiggle at all. I’d worried that the swing and shift knobs on the front and back would be tricky to reach, especially when base tilts are used, but they are readily accessible and not at all  awkward. Also, everything on the camera comes apart very easily for maintenance. And it’s really quick to set up, I can leave the lens on when it’s in the bag, or install the lens I want before putting it on the tripod.

The weight isn’t ideal, but not horrible either. A little lighter than my other 5×7, probably around 7 lbs. I may eventually mill some ‘lightening’ holes in some of the hardware, but the main culprit is the stainless steel knobs-  almost two pounds there alone. I used 10-32 for all the movement knobs except the for the focus knobs, and there weren’t a lot of options available in that thread size that had a decent outer diameter. I’m tired of tiny knobs. Eventually I might get a lathe and make some knobs out of plastic or aluminum. [McMaster sells a nylon version of the 10-32 knobs I got in stainless steel, and I did order a few of those just to try out but they’re not very good. They’re expensive, the thread varies from knob to knob, and they have a very poor overall finish.] The rear shift uses 1/4-20 thread so I used lobed aluminum knobs that can be torqued down easily regardless of position, then milled them down in thickness to fit in the space under the rear standard. Probably would have been easier just to make some.

The bellows are just right, perfectly sized for the extension and movements. I can’t say enough good things about Rudy at ECBuyonline. They were made exactly to my requested dimensions, square with no twist, and all the folds and creases are perfect. I’ve made my share of bellows, but knowing this sort of quality is available at such a reasonable price I never will again. They really put all of my efforts to shame.

Modified the Kelty Bag for the new rig. The slightly larger camera size means I can only carry 6 film holders now instead of 12, but I never shot more than 12 sheets of film in one outing anyway and the pack is now quite a bit lighter.

I really want to use this, so rather than take photos of all the camera’s possible contortions I’ll just list the movements for now. Front movements: 45° axis tilt each way; 45° base tilt each way; 100mm rise/ 45mm fall; 15° swing; no shift. Rear movements: 45° base tilt each way; no axis tilt; 35mm rise/ no fall; 15° swing; 35mm shift each way. Not including the base tilt workaround, the max extension is 360mm ; minimum is 100mm. Just right for the range of lenses I use.

I’ve only taken a few dozen exposures with this now, but so far I really like it a lot. I do need a WA bellows pretty badly though, so rather than deal with the long turnaround for custom work, I went ahead and made one.

I’ve spent so much time in this dark hole, might as well take a photo of it. Note the scraps of old camera projects in the burn bin. Can’t help but wonder if this new camera will have the same fate.

100% crop from right edge of above photo (red rectangle in nav panel). Right click and select ‘view image’ from drop down menu for full size jpeg.

Since this build diary was written in real time, some of the fuckups get lost in all the verbiage. There’s a digest of those here:

5×7 Part 4, erratum