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View Full Version : Lensboard/panels: Cutting apertures in wooden ones (for plate camera)



Rob_5419
10-Mar-2007, 17:48
Wonder if anyone here might care to share how their wooden lensboards are cut to enable a lens and shutter to be fitted and mounted therein.

I've found that mahogany actually cuts very easily in the direction of the grain. However this is in straight lines. I wonder how people create apertures for lenses in wooden lensboards, without sending these off to a specialist/machinist?

Thanks.

John Cahill
10-Mar-2007, 19:47
I locate the exact center of the board using a straight edge line from each corner. I dimple a starting point in the wood with a small pointed punch.

I use an adjustable circle cutting bit, adjusted to the size I need. I practice drilling the hole on scrap wood, test fitting the lens just to make sure. When I am certain, I slowly drill the board itself. I do not know how this bit will work on mahogany, but it works on oak and birchwood plyboard.

Jim Jones
10-Mar-2007, 20:32
To reduce splintering with a fly cutter (adjustable circle cutter) I drill a hole for the pilot bit. Then I turn the fly cutter backwards a few turns to slightly score the lens board front and back. The final cuts are made halfway through from each side. If the lens board is firmly backed while making the hole, it can be cut entirely from one side. If a lens board is too thick to mount a lens with a jam nut, the board can be built up from thinner layers with a lens-size hole in the front layer and larger holes in the others.

Gene McCluney
10-Mar-2007, 22:05
On thick boards, you can also take a router bit on the back side and take off some thickness around the lens hole, so the jam nut will get to the threads. You can even be a bit sloppy, because no-one will see on the back, especially after you paint the back side of your lensboards flat back, as you should.

Richard Kelham
11-Mar-2007, 11:00
I use a distinctly lo-tech approach taking laminations of good quality birch ply and attacking them with a fret-saw! Clean up with emery paper (and chamfer the inside edge if necessary) and there you are about half an hour of your time and a few pence for the ply. For smaller 100 x100mm boards I use black sheet styrene as sold for model making; this you just score with dividers and push out.



Richard

Rob_5419
13-Jan-2008, 16:10
This thread came up at the bottom when I was writing in this one:

http://www.largeformatphotography.info/forum/showthread.php?t=32254

Funny revisiting a thread, almost a year after I posted this.

Just some feedback:

I worked out how to do this on wood panels of various thickness. As Jim says, a metal drill bit using a circular saw attachment on a drill works perfectly. The wood needs to be clamped down on at least two sides to stop it from jigging everywhere underneath the saw. The drill bit protrudes front forwards and drills the hole first, before the circular saw moves in action.

I got a set of circular saws ranging up to 65mm from a DIY shop. They fit on any standard drill by altering the bit with the chuck. You can get these for huge sizes too, but it becomes harder to steady.

After drilling out the hole and sanding down the board, I've been staining my boards and then varnishing. Drying for a day, then resanding and revarnishing. The wood stain looks good. Flat black paint on the reverse is fine.

Lo tech works fine ;)

EdWorkman
13-Jan-2008, 17:28
I've done them , so far, without the correct bit- [way too small],
so I have enlarged a small hole to the correct size by carving and filing. I also have drilled multiple holes around and inside the periphery for the rough opening. That's the front plate, 1/8'' thick. Then I have built up the inner thickness as a square using glue and wood strips.
I had the time, and it didn't take all that much more than having the powere tools.

Tracy Storer
13-Jan-2008, 21:51
Jasper circle cutting router base:
http://www.woodcraft.com/family.aspx?familyid=3582&refcode=07INAFFL

mrladewig
14-Jan-2008, 12:40
I cut my lens board holes with Forstener bits and a drill press. Forstener bits will probably cut a much smoother and more consistent hole than a hole saw. 1 1/16" matches #00, 1 3/8" should match #0 (will test in a few days) and 1 5/8" matches #1

With this method, the fostener bit can cut a very straight hole and the outer teeth keep the wood from splintering across the grain. Then the inside cutting faces trim away wood nice and flat as it bores down. The outer teeth do protrude down a bit more than the inner cutting faces, so you need to keep that in mind.

Bubinga (African Rosewood) lensboard I made for my Tachihara and #00 compur.
http://www.ladewigs.com/Gallery/d/608-1/lensboard_04.jpg

Sanding down this 1/8" stock to 3/32" was a pain, but my 65mm needed the thinnest lensboard possible to focus. Bubinga is fairly hard and dense so the sanding is slow. Now for my longer lenses, what I do is use a larger forstener bit on the backside to countersink a hole for the shutter's retaining ring. I hand carve the retaining clip recesses in the board, which takes me about an hour. Then I just do a finish sanding to the front and back of the board before finishing. In my case I used matte black spray enamel on the back sprayed first and polyurethane on the front and sides.

Mel-

John Kasaian
14-Jan-2008, 14:12
12 guage 1oz #8 shot at the correct range. Use a improved cylinder choke for a copal #3, modified for a #1 and full for a #0. ;)

You guys with your fly cutters scare the daylights out of me! The thought of one of those things launching off a drill press---:eek:

mrladewig
14-Jan-2008, 14:27
12 guage 1oz #8 shot at the correct range. Use a improved cylinder choke for a copal #3, modified for a #1 and full for a #0. ;)

You guys with your fly cutters scare the daylights out of me! The thought of one of those things launching off a drill press---:eek:

Funny John. Aside from shooting photos, I also shoot trap.