Asanuma project camera – base plate ponderings

Well, now that the back is essentially done, I’m left to figure out a base plate design. I’m torn between two basic designs – one leaves the camera intact, one permanently alters the original configuration. Ideally, I think I’d like to fill the base hole with a mahogany “roundel” into which I’d install a tripod mount. But I’d need to rout a larger rebate around the inside of the hole in order to make a mating piece of hardwood. Unfortunately, I’d have to file through peened parts on the base in order to have a flat field for the router base to ride on. Or, I can make a plate to extend the height of the base over the hardware, adding additional work, opportunity for error, and material waste.

Alternatively, I can build a plate that mounts to the bottom of the existing base with three mounting bolts through the existing spider assembly. This adds weight to the camera, extends the thickness of the folded camera, and leaves little metal protrusions on the bottom that will, inevitably, scratch the bejeebers out of our new kitchen table. Not good.

I’d like to keep the camera’s original configuration intact, but would like the permanent, lighter solution to be more easily implemented. Hmm – decisions…


Asanuma project camera – 4×5 insert, so close

So close...

Insert’s done, except… I was two screws short on the ground glass clips. Rookie mistake. Drat. I’ll be heading to Ace tomorrow to pick up a couple more #1×1/4″ brass screws, then it’ll be officially done. Then I can start in on the tripod mount, whatever that may end up being.

Asanuma project camera – 4×5 insert, oiled

I’ve applied about four coats of tung oil “finish” (a mix of tung oil, most likely polymerized, and varnish) to the cherry on the 4×5 insert.


I’ll let this cure a while, then tape off the film holder recess and spray the rest with lacquer. The underside of the insert will be sprayed flat black. Ground glass retain clips (Tansu screen corners) are on order – once the glass is installed, this insert is finished! I’m pleased with how this project is turning out. It should prove very functional.

Next task: Create some form of tripod mount for the camera. This will be either a round base plate mounted to the existing spider on the camera’s underside, or a mahogany “roundel”, made to fit the hole in the camera’s base.

Asanuma project camera – 4×5 insert nearing completion

In the last two days, I’ve made same progress. Yesterday, I ground some glass for the back:


Messy, but effective. I use a lapping glass and 500 grit silicon carbide lapidary grit. Light pressure, lots of rinsing and checking. I cut the glass to fit the back. No clipped corners on this one.

I then installed the springs:
Getting closer...

The springs are surface-mounted; this first pass, I left the turned ends proud of the surface. I thought I’d see how they worked, and if too tight, I’d create recesses for the ends later. I used 3/4″ x #17 wire brads as mounting pins; just set the frame in place and press the pins in to mark their locations.


Predrill the holes so as not to split the wood, cut off the heads of the brads, and tap them in place. And it worked well. Except the springs applied too much tension as installed. I needed to recess the ends. Easily done with a Dremel and straight bit.

After recessing the ends and playing with locations a little bit (some tweaking is always required), the back is working as planned. Here ’tis, with a film holder inserted:


An appropriate amount of force is applied to the holder, but there’s easily enough flex left in the springs for removal.

I have only a few more things left to do before applying finish: Cut the hole for the plate back’s locking tab, ease the back of the ground glass holder grip to make grabbing it a little easier, and maybe rout a recess under that end in the insert to facilitate even easier insertion and removal of the holder, pending a bit more testing. Finish sand, ease the edges, and apply tung oil finish. Wait a few days, lacquer, and it’s done.

Asanuma project camera – ground glass holder

The thickness of the ground glass holder is crucial to setting the ground glass at the plane of focus or film plane. I measured carefully the distance from the edge of a holder to the surface of a sheet of undeveloped film and got 3/16″. My glass is 3/32″ thick. So I planed the cherry to just a little proud of 9/32″. I laid out the the pieces and ripped the cherry to dimension:


Then I crosscut the pieces to final dimension and did a quick check for fit:


The pieces are joined with half lap joints cut with a horizontal router table. It’s not difficult, but more an exercise in transferring dimensions from piece to piece. Half lap cuts on pieces this narrow and thin, though, are a little hairy. I cut close to the lines and clean up with a chisel.

The final frame, dry fit:


Next step: Lay out and cut the rebate for the ground glass, then glue up the frame. The trick with the cuts will be the two stopped rabbets to be cut in the stiles. More on that later…

Asanuma project camera – fitting the film holder to the insert

First step in making an excavation for the film holder is laying out the recess. To do this, I center the film holder’s window over that of the insert and strike a line:



When the area is marked, I turn to the router and a rabbeting bit. I size the bearing to be just a little larger than the marked line so the holder isn’t too tight in the back. Then I rout the recess. The recess needs to be a little longer on the end, and open on the front. I rout these areas free-hand using a hinge mortising bit. The edges and round corners are finished using a chisel:



A quick check shows we’re on the right track:


The film holders have a double light trap on the darkslide end:


To Make the excavations for the light trap, I use a Dremel with a router base and round burr cutter, and rout the open end of the insert free-hand with the router and hinge mortising bit. The edges are again clean up with a chisel.



A final check shows the light trap is a perfect fit in the new insert:


The next step is to build the ground glass holder. This is a delicate project, as the pieces are on the order of 5/16″ thick, and the rebate for the ground glass has to be placed at the film plane. I’ll start by planing my cherry this afternoon…

Asanuma project camera – 4×5 insert base construction

After planing down the scrap board of curly cherry I found lingering in the garage, I milled the parts for the base of the 4×5 insert. The wood ended up just a little over 5/8″ thick; enough for some stand-off of the holder. I laid out the widths needed from the plate back and ripped parts from the board. To the rails, I milled a small tongue to fit under the rails on the plate back. They fit!



I ran a groove on the insides of the rails for the tenons on the stile ends. I did this using the tablesaw – run the groove in approximately the center of the rail, flip it end-for-end and run the groove again. Results in a perfectly centered groove.

I set the horizontal router table for approximately the tenon thickness needed for the groove and start adjusting the height of the bit, cut after cut, in tiny increments. This allows me to precisely fit the parts. However, I always stop a little short and finish up with hand planes (in this case, a Veritas shoulder plane and a Stanley Sweetheart #18):


After adjusting the fit, I test the insert out in the back:



Confident everything fits correctly, the assembly gets slathered with poly glue and will sit in clamps for several hours:


After the glue is cured, I’ll clean up the foam-out, mill a small rabbet in the end of the insert to allow it to sit over the end retainer strip on the plate back, and layout the cuts for rabbeting for the ground glass holder.