Camera building log, 2009
January-March
Much hiking on endless BLM roads. I decided I need a smaller, much smaller camera. I love the one I made a few years ago but let's face it, it's bulky and heavy.
April 2
Had a piece of nice cherry in the shop, started milling. Rough, oversize. Will sticker for a week to see if there's any latent tension, but it ripped very nice, no obvious winding, twisting, etc.
April 2-10
Design all week. Worked out rough idea with CAD and cardboard silhouettes. Mostly cardboard. Low tech but pretty effective in finding pivot points, brace lengths and extension.
I need to decide on folding or nonfolding wide angle design. I dig folders, my 4 previous self-builts are all folders, but I can appreciate the utility of Ebony’s nonfolding models, but I think I would miss the base tilt on both standards. Would really like a reversing horizontal to vertical back that's not too fussy. Under 8 pounds, and smaller than my original 5x12, and can make change for a $50, sure why not.
April 12
Fabricating parts. Starting with back, need to get as small as possible and still work with my existing holders. Looks like 8x15 will allow enough room for bellow pleats. Making rear box 8 x 15 x 1.5”. Still not sure of fold/nonfold design.
Had an idea for a reversing back. Use a platform of dovetail slides for the rear standard brackets to slide to the differing widths needed for horizontal or vertical orientation. Will mock up some parts tomorrow.
April 13
Using some aged rosewood for the dovetail platform. Very very hard and has a great strength/weight ratio. Cherry is a a bit too soft and I think the joints would round over and get sloppy with use. Might make final version in aluminum, but the rosewood seems quite rigid. Man the stuff seems to wear like iron. I stop-slotted the platform for the brackets to slide in and out on either side. The knobs will tighten on a stud threaded through the rosewood slot into an aluminum plate that slide in a wide dado routed in the reverse side of the rosewood. This will take the load off the dovetails when tightened. The dado relief is mainly to let it slide easily once mounted on the rear extension carriage.
dovetail slides for rear standard
I’ll have some aluminum flat stock on either side to reinforce the platform and be a bearing surface for the carriage. Needed to stop there until I decide on an overall design. The carriage will need a rear focus- forward mechanism if I make it a folder with a large bed. On a non-folder, I’ll only need to slide the back forward enough to make it a compact and easy to store in the pack. Might just make a rigid rear standard with no base tilt, but I don’t like that idea- if you drop the bed there’s not enough center tilt on those to re plumb the back before it interferes with inserting the filmholder. Also running into deadens with the front- if the back switches to vertical I’ll need a bunch of front rise to get to the center of the frame.
Bottom view of rear carriage.
Side rails are bearing plates for
rear shift and swing and also reinforce the dovetail platform.
The shorter bearing plate rides in a shallow dado for clearance when finally mounted to the rear extension.
When tightened down they provide the structural base for the rear standard brackets.
rear shift and swing and also reinforce the dovetail platform.
The shorter bearing plate rides in a shallow dado for clearance when finally mounted to the rear extension.
When tightened down they provide the structural base for the rear standard brackets.
April 13-16
Back and forth on design, deadens. Like a catch-22, can’t design the standards until the bed is thought out, can’t design the bed until everything else is thought out. Trying some ideas for the telescoping front standard, nothing worth mentioning yet.
I did think of having a horizontal slot in the rear standard pivot bracket. That would let me side the back forward enough to make it more compact for my pack, and give some limited center tilt as well. So then I'm thinking I'll just do a nonfolder with base tilts on both standards. Unorthodox, but hey I like base tilt. I really like the idea of the camera being ready to go, just set in on the tripod. Could even leave the lens mounted.
Played with some ideas for a short- really short- bed. I was thinking if the bed was only as long as my current camera is wide it would still fit in my bag and be much lighter besides. I only need 14 inches of extension since I sold off my 450, and don’t really do any macro stuff with any lens longer than 250. Might be able to get 14-16 inches with a 4-stage extension on a 4.25” bed. Single rear and triple front. I have some channel aluminum for plywood edges- the .25 and .375 stuff are perfectly mated and slide smoothly.
April 16
Made GG frame and back and front standard frame. Will cure under weight for 3 days until moisture levels restabilize. I had a back warp once out of the clamps due I think to the moisture from the glue and wiping the squeeze-out up with a wet rag. Not taking any chances.
I NEED TO THINK before just by default making everything small and thin. I made the GG frame so thin I almost don’t have enough thickness to put the ground glass in the same spot as the film in my film holder’s T-dimension. And I really don’t want to make new film holders. I also realize that I have no hope of making a folder because the front standard would have to be very short to allow it to fit inside when folded. Especially now that I made the rear platform so wide to accommodate the sliding dovetails. I guess I could make the bed longer than the rear box is tall, but doesn’t that sound awkward and ugly. I guess the decision has been made for me. No wonder I made the first one so big. It needs to be big to accommodate all the hardware when folding. If I can’t work out an idea for a telescoping front standard I might shelve this project until I do. I wish I would have written journals about the other cameras I've made, so easy to forget all these elements of design over time.
rear standard and back
April 17
Fixed the thin GG frame issue. I used the garolite frame from the obsolete scanner insert I'd made for 5x12 negatives and it was almost a perfect fit to the bottom of the gg frame, just trimmed the opening flush with a bearing bit on a trim router. It'll pad it out enough to let me recess the ground glass flush with the frame at least. I can live with that. I live to hack another day.
Have the working idea of the bed. I’m forgoing the tongue and groove slides to save space and allow for the extra front extension. A top rail of .125" aluminum over the stationary rails will be plenty to hold down the extensions. I might regret it but I’m milling slots just to keep things moving. Front and read base plates for shift, and rear sway braces and pivot brackets. I’m leaving the base plates and sway braces long and will cut when I sort out the exact pivot locations.
garolite shim for ground glass
frame
April 18
I have a working solution for the front standard. Well, close. The main front standard will be rosewood, L- shaped in plan view to provide a bearing surface for the second stage of the standard which will be 1" double-slotted .125" stock. One slot will lift a secondary standard into the vertical orientation range, and the second will allow fall and rise when in the horizontal range. The slots are close to the outside edges though, might not be strong enough. Might need to use 1.5" wide stuff. Also, the knobs will bump into each other when passing unless I find/make something very specific and specialized.
idea for telescoping front
standard
Finishing up GG back. Cut recesses and a nice taper on the spring rails, made the aluminum torsion spring housing and mandrel points. Need to order some more torsion springs.
milling spring rail recesses for spring arms- this is the final pass of many lights cuts
Spring mechanism- aluminum housing with mandrels and spring arms for each side
A screw post is reversed back into the housing to leverage against the torsion spring on a mandrel-
each assembly needs a left- and right-wound spring.
The extra mandrel thread and screw heads are eventually filed flush.
-Hard to see but the ends of the spring arms that mount to the gg frame have to be slotted a bit to allow the gg frame to lift high enough for holder insertion.
April 20
Reworked front standard. Re-milled the 'L' parts in cherry. I cut a slot in this part to relieve the aluminum a bit, only one slot in each part instead of two in the aluminum. That’ll also help keep the knobs further apart so they don’t clip one another. Man my arms are tired from cranking the table on the mill! Still, beats filing those slots by hand, I remember those days too well. Added cross strut to connect aluminum standards and a piece of angle aluminum to capture and ride against the cherry standard.
Finished front standard.
The knob on the telescoping stage also controls center tilt,
and is mounted on a cherry spacer to clear the first stage.
The knob on the telescoping stage also controls center tilt,
and is mounted on a cherry spacer to clear the first stage.
Started working on a custom aluminum knob to tighten the rear shift and swing movement. Should hide well under the carriage with enough of an arm to stick out to tighten, and also have enough of a bearing plate to tighten the platforms securely. Thought of trying to mill on the mill but ended up making it with a hacksaw and file. Made for quite a teeth setting afternoon. I think I impacted my wisdom teeth a bit more.
rough milling of rear
shift/swing
knob. Made it much too thick, ended up cutting it half the long way.
April 21All the plans and dimensions are final for the extensions and bed, so I can finally make that. Using a traditional breadboard design for the base. Two solid bearing surfaces capping a thinner board in the center for the tripod mount. Running out of cherry. I boogered the first attempt- made the center part of the breadboard too short- forgot to add enough for the tenons. Made bellows frames, cut aluminum stays for the recessed rear support. Gave the bellows frames, light trap areas on the wood parts and the aluminum stays a few coats of flat black enamel.
April 22
Fitted up the base for rails and movements. Mortises in the pinions and shafts and dadoes the racks into the extensions. Re-bored the 1/8" spur hubs for the 3/16" shaft- don't forget to do this 1/64" at a time- jumping from 1/8 to 3/16th doesn't work. For the final front extension I milled slots in the .375 channel for a tightening thread to engage a nut to ride in the recess there and tighten once extended. Put the extensions and bed all together to test- I've been worried it might be a little loose racked all the way out, but it really is amazingly rigid, it'll hold my 6lb xenar no problem... Ordered knobs. Love the look of knurled stainless controls but they are heavy, and they are uncomfortable, especially in the cold. Any pricey. I got the Novogrip stuff from Reid Tool- wing shaped knobs for the standards and round ones for focus and locking. Dirt cheap, light and comfortable to crank down on. Had to get a few stainless thumbnuts and screws for several parts- not much other option in the 6/32 thread size. Trying to keep this project under 100 bucks- I did have much of the materials on hand already, the gears and hardwood and most of the aluminum, but do need the knobs and some aluminum, lacquer, and incidentals. Should come in well under that. Sanding and polishing parts, getting ready to spray. I’ll lacquer the aluminum as well, even though that’s not the best solution. I’ll try plating or anodizing some day. Very windy this week, spraying outside so need to wait for a calmer day.
dadoes cut for gear racks
bed fitted with spurs and rails
finished bed racked in
bed at full extension
April 23
Lacquered all day. Thought I could work on the bellows in between coats but had to spray in light coats because it’s still pretty windy out.
spray day
April 24-25
Bellows. I hate them so. I'm doing the patterns a bit differently- making the actual peak and valley cuts on the top and bottom patterns, might make it easier to fold. I did a paper mockup but still the pleats are folding oddly. I think the geometry of this isn’t quite right. The front standard is fairly close to the size of the back on the side, so there’s not much taper there- 7� inches to 5� . But on the tops and bottom it’s 14� to 5� . There is this one pleat circling the exact center that's deformed, and seems to separate the bellows into 2 perfect shapes. In other words, before and after this one pleat everything is just right. I think the mockup worked because it was just kraft paper, no stiffeners. I should have just made a @!$# bag bellows- I rarely use anything longer that a 250 lens anyway.
bellows with cemented patterns
Bellows glued to frames. Homely, but functional
April 25-26
Assembly day!
some assembly required
Leaving a lot for this stage. Knobs and springs showed up
yesterday, so I can cut the shafts to length and finish up the spring
rails on the back. The round knobs have a cap that pops out, which made
it easy to modify them into locking knobs, with a locking nut on the
end of the shaft to keep them from spinning off the end. The focus
knobs were trickier. The shafts I use are 3/16 and the knobs were
1/4-20 internal thread, so I had to use a 6/32 to 1/4-20 thread repair
insert, pin that with a set screw, then bore that
out to the final 3/16th, 1/64th at a time, with cutting fluid,
then finish pinning the setscrew though to the
shaft. Sort of a PIA, but there just are no stock knobs available for
3/16th shafts. There are plain unbored hubs available on stainless
steel and black oxide knobs, but as mentioned they are heavier,
pricier, or both. I was using 1/8 shafts on previous cameras, which is
easy to cut into 6/32 thread, but lots of torque and backlash on such a
thin shaft...Anyway, I also need to make
a custom knob for the front shift
swing movement, something like a thinner version of the rear.
re-boring focus knob insert to fit shaft
Placing the locating pins for the back gave me an idea to make it flippable 180 degrees... I’ve often been on a ledge and getting the holder in meant living a little dangerously. Nice if I could just flip the back 180. That would make inserting the darkslide in after taking a shot much, much easier in the vertical position- just flip the back so you can insert the holder from the bottom instead of craning from tiptoe to see the slot.. I just installed the bottom pins, flipped the back around and used those pins to locate and install the top clips, then used the bottom clips as a pattern to drill the reversed 'new' bottom.. Er, yes that's it. I cut the spring clips the upper pins mount to out of an old putty knife, the easiest source for spring grade stainless steel. Again, use cutting fluid in the future- the bottle is right there, just reach for it.
Pins and clips for mounting the back. Pin will only have about 1/8" showing after tapping in.
Rigid clips for the bottom, spring steel for the tops to facilitate removal
Laying out 2 spring clips in some readily available stainless steel spring stock.
One hole for a pin, two for mounting screws.
The secondary mounting screws will serve double-duty as thumbscrews for quick-change bellows release
Notice the 'bluing' around some of the holes- I got lazy and used no cutting fluid. Much harder to polish out the blue than reach for the bottle of cutting fluid, dummy.
Finished the spring rails and back. Had to pare down the rail ends in fitting them, need to resanded and lacquer them again.
Tenon to mount the spring rail to the spring housing and
the assembled back. The spring rails are tapered from the thickness
of the spring housing down to the thickness of the ground glass frame for a cleaner look.
More assembly. Forgot I still need to sort out the quickchange hardware for the bellows, mill the lensboard tabs, etc. I though of hiding the bellows quickrelease in the top pin clip. I had to remill the spring clips to make them a bit longer so the mounting screws will fall inline with the bellows frame to capture it. I installed a threaded insert behind one of the mounting screw holes that will allow a thumbscrew to thread through and catch the top of the bellows frame. The bottom of the bellows frame is captured by a length of .25" aluminum channel running the length of the back, which is also part of the frame that makes up light trap for the back.
Picked up some non glare glass in town to grind, also some plexi to experiment with- might make in even lighter using acrylic instead of glass. Right now it’s on pace to being ~7 lbs. Six pounds now without the ground glass and bellows installed. Grinding the plain side of non-glare glass won’t ghost with the acid side, and the lack of reflections when composing is a great help in focusing. I ground from 25 micron aluminum oxide through to 12 micron, any more it starts to get clear again. I scratched in grid lines with a ball point pen. Not just any pen will work- only the cheap ones seem to seize up enough to actually scribe the glass. I print a grid on some paper and trace on a lightbox with a straightedge registered to the printout. Scratching the ground side makes the lines look illuminated when composing, but it is a pain to regrind if you screw up. Easier just to start over with a new piece of glass. But it’s not difficult if careful. I haven’t tried scribing the unground side. Finished too late to test, just getting dark. I have to be in Port Townsend early tomorrow so I guess I’ll take it with me and test it there. I was going to take it anyway, but was hoping to at least run a sheet though it to check for GG placement and light leaks first.
My older 'prototype' 5x12 on the right.
Normal, and Vertical orientation. Up to 20" of extension when using the front base tilt trick
April 28
Had a great day at Fort Worden in Port Townsend. Took four shots, but was afraid to take too many in case of some catastrophic unknown problems. But after developing the first negs everything looks great- plane of focus looks right on, no light leaks. Even took a long shot in full sunlight, no internal flare, leaks, etc. Sweet. The camera is a joy to use, I must say. The telescoping front standard works better than I dared hope. The H to V switching is pretty smooth, a bit fussy with the tiny base pivot knobs. I’ll need to make some ‘caps’ to press fit over the knurl of the thumbscrews and make them easier to tighten. I also need to cut the threads down- the time consuming part is just unscrewing them all the way out. And make some !#@$% bag bellows.
But I'm most pleased. I achieved most everything I set out to do, mainly lighter (under 7lbs! down from 11lbs- no, actually 13lbs, including the 2lb mounting bracket I had to carry around for vertical shots) and smaller. Also got a reversing H to V back, as well as some stuff I didn't know I wanted in the bargain. Odd looking little bugger, but works a treat.
The 180 switch back paid off on almost the first shot. I had to set up right against a wall to center the composition. If the back didn’t reverse 180 I could have never gotten the film holder in. And the bellows does seem to work well, even with the 6" lens.
first shot- Fort Worden State Park
May 23
Asymmetrical taper/ Bellows redux-
Figured
it out finally, finally, finally.
I had the offset geometry of the pleats completely reversed. Typically for a
bellows with a symmetrical taper- that is to say a taper that is the same on all 4 sides
and square
both front and back- the pleats folds have to be offset in order to
accommodate the
slope of the taper. The offset is typically found by placing the long side of a 45/45/90
triangle
along the slope of the taper and drawing a peak of which the bottom 45 degree vertices intersect with the
major
fold lines. The intersection with the 90 degree peak is the offset asymmetrical fold line,
hence force called the minor fold. For
a tapered bellows to grow in size the 'up' fold has to be bigger than
the 'down' fold. In a symmetrical tapered bellows it doesn't matter
which pattern you take the offest from, they're all the same, so I got
in the habit of just using the top pattern, which is where my brain had
pinched shut.
For a
bellows with an irregular (compound) tapers, that is to say, a bellows tapering from a rectangle in the rear to a square
in the
front, the minor fold for the wide tapering side is found from the
adjacent taper, the side pattern, not from the wider taper of the top
pattern itself. I wasn't thinking about it in 3 dimensions- the pattern
doesn't move within it's own 2d space when folded obviously, it moves
in the
space of the pattern perpendicular to it. The more difference
there is between the taper angles of the sides and top/bottom patterns,
the more critical this
distinction. (I didn't notice it as much with my older 5x12 because
there was much more taper on the side patterns, but still there was
always something not quite right about the bellows I made for it.) So,
to find
the minor fold for the top and bottoms patterns, the triangle is placed
alongside the slope of the taper on the side
patters, not
the top and bottom pattern, and temporary marks are
made to find the peak and intersection. The distance to the
intersection is
found by measuring from the major pleat line, and this measurement is
transferred to the opposing pattern. The reason for this- and this is
what kept confusing me through all the prototypes- is the side pattern
is the one that needs to grow as the folds go up the bellows, so it has
to be the one with the more offset folds. The top and bottom pattern,
while having a much greater taper, essentially does not grow at all as
the bellows does because there is barely any taper along the side
pattern. So basically the offset dimensions are found by
the adjacent pattern, not from the patterns themselves.
finding and transferring offset fold
1)45/45/90 triangle is placed along taper of side pattern to find peak/minor fold point. This will not be used on this pattern!
Instead, (2) distance is measured from major fold line on side pattern and then transferred to top&bottom pattern, the adjacent pattern. You can see in pictures 1 and 2 how different the peak point is from the half line, which is the actual offset fold line already partly drawn in for reference.
3) Ok, so then, all of the minor fold lines are ticked off and drawn by squaring off the centering line on top pattern
4) Square (used a 30/60/90 since I just broke a corner off the 45/45/90) is place along centering line of side pattern and intersected with the corresponding minor fold line of top pattern- and volare!
this is the offset fold line for an asymmetrically tapered bellows.
*notice the space between the two patterns- this is the spacing used for the type of pattern I normally use, plain tapers without all the peaks and valleys cut into the patterns. The spacer accommodates the space used by the folds of both sides and is 1/2 the dimension of the major fold. I.e. if the space between each up fold is 1 1/4 ", the spacer will be 5/8". I made this spacer part of the top and bottom patterns and perforated the cut line so I could glue it down as one piece and help register the side patterns, then easily remove the spacer strips before gluing on the liner.
Just finished. It really almost folded itself. Will leave under weight overnight to crease the folds and compact it, then trim and glue to the frames.
Old v new method. A great relief- it's pretty frustrating to spend a lot of time and effort making a camera only to have a hideous bellows tying it all together.
Done for now