Cutting holes in lensboards
So I've realized I have too many LF lenses I've not shot yet. I can make acceptable lensboards with local hardware store lumber, but does anyone have a good trick for cutting the holes in the center. My Dad has an adjustable fly cutter with his milling machine, but there must be some sort of woodworker's tool bit that is quick to adjust and easy to use.
Hole cutters are available as power drill attachments, usually as an arbor (holder) plus interchangeable rings and with a center pilot twist drill. There are different qualities of metal cutters, some will just cut wood, others will do thin metal. Also, sizes vary, check a couple of sets and you might find cutters with 35 and 40 mm diameter, just right for #0 and #1 shutters. Just draw two diagonal lines on the back of your panel to mark the center, clamp the panel up securely with a piece of thick scrap lumber behind it for the pilot drill to sink into and you should find you can cut a hole in about 10 seconds! If the lens panel material is splintery, it might be better to cut halfway through and then turn the panel over and finish it from the other side.
Originally Posted by athanasius80
As David stated you can get different sized hole cutters, or you can use a paddle bit on hard woods, or an adjustable cutter that uses an arm with a cutting blade and a center pilot bit. Most of these really should be used with a drill press, both for accuracy and safety. Check Rockler.com for really nice tools, but look at Sears for more affordable versions. Always, I repeat ALWAYS clamp your piece very well when drilling holes - the bits can really bite and put you in a world of hurt in the blink of an eye if you are not paying attention to what you are doing.
Don't get me wrong, it's not that dangerous if you just pay attention. I've made a number of lens boards, and need to make two more right now actually! It's a hell of a lot cheaper than buying pre-made boards, and you can choose the wood and the finish to match your camera when you do it yourself.
I use one like this thing. It's a heavy chunk of metal to have whirling around on the end of your arm. It doesn't cut a straight hole profile--the hole edge will be angled. Works OK with birch plywood.
A hole saw, Lenox, in a drill press with the board sandwiched between some thin material can give a very clean cut hole. The circle cutter works good too just be careful and go slow. If the hole saw, a barrel cutter, is not the exact size I use a drum sander to enlarge the hole slightly. I have made both wood and aluminum boards for enlarger lenses and taking lenses.
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I, too, endorse the fly-blade cutter Derevaun linked. I picked one up at a 'disposable' tool store along with a 'spade' bit set and a conventional holesaw set...2.99 each.
The hole saw set was a piece of garbage...the collet was the wrong size and slips right thru the center hole. I Murray-rigged one hole one time and haven't even taken the time to find a garbage can for it.
The 'outrigger' fly-cutter and a digital caliper allowed me to actually make a 2.205" precise hole for a heavy lens, and I decided at that price I could buy more than one. I set the blade spacing and make a practice cut & tweak.
I also recommend safety glasses, a hard had and two baseball cups before using some of those imported tools.
They're usually dripping in anti-corrosion stuff (dirty oil at best) too, so clean 'em in solvent first, if you care.
I would certainly also advise against cheap tools, these are often made of incredibly weak metal which breaks under very light loads. The thing about a circular hole cutter is that it balances itself, as it contacts the workpiece surface around the full periphery all the time. I agree that if you use a device with an outrigger cutter, the best choice is a bench drill, otherwise the cutter may behave in a unpredictable way.
I use a hole saw and my grandfather's old hand-powered drill. I've tried using an electric drill, but prefer the extra control I get by actually turning the handle myself - it helps me make a nice even cut since I don't have a drill press.
Since the hole saws are never exactly the correct size I drill the hole slightly smaller, then expand it by using a file or a knife depending on the material and how much is to be removed.
-- Ole Tjugen, Luddite Elitist
Another hole for the fly-blade cutter in a drill press stand. Choose one with a single blade rather than to model with double blade, those are more difficult to set to the exact position.
Actually, I was looking for some fixed size hole cutters yesterday evening to see if the available sizes could match shutter sizes and could only find one that would fit a size 1.
There are more drawbacks than advantages with fixed size clock drills:
- expensive. The adaptor costs more than a complete fly-blade cutter;
- difficult or almost impossible to find the correct size;
Advantages? I guess they last longer.
So I sticked with the fly-blade cutter. A single one serves me in cutting shutter 0 sizes up to the 122.5mm diameter needed for my enourmous Tessar 360mm f 4.5.
My vote goes for this type of device also. I picked mine up at Lee Valley Tools. It's slightly different with only one cutter, but it does cut a nice straight side on the hole
Originally Posted by derevaun
CAUTION ::: :: read the cutting speed (rpm) instructions and don't feed the bit too quickly or the cutting edges will burn and become dull.
Last edited by John Bartley; 12-13-2006 at 09:56 AM. Click to view previous post history.
Reason: spelling error ... doh!