I often read posts from people having trouble setting angles on machines or wherever. So I thought I’d share what I’ve learned over the last thirty years, and I realized I’ve been using, thinking and in some cases obsessing about angles for a long time. My first career was a land surveyor, and obviously that was nothing if not angles and distances, down to degrees, minutes and seconds.
But I moved on from surveying to wooden boat building in 1982 and have been doing that ever since. Boats are an amazing combination of angles and bevels constantly changing from one end to the next. Of course a sliding bevel gauge is a primary tool but if you don’t have a way to set a particular angle all you can do is compare and transfer. So the first thing I made was a bevel board. It’s drawn on about a 32” square of plywood. It’s not difficult to make but just a bit tedious. It doesn’t wear out so if you make one take your time and accuracy is paramount. As a boatbuilder I would use it to make a bevel stick to quickly find bevels on a lofting so frame bevels could be cut on the bench instead of trial and error once the frames are set up as I have often seen in some shops (professional shops in more than one case). Here is how I made mine. It’s very useful even if you don’t build boats.
Start with a square of plywood 32”x32” not much smaller than that. Leave a margin all around and draw a square 30”x30” . Check diagonals and the lengths of the four lines. When you are sure it is square, starting from the lower left hand corner I made a grid of 6” squares I think but they could be any spacing you want accuracy is more important than whether you use 4”, 6” or just one at 15”. Next you will need to draw an arc with a radius of 28 5/8” or 28.625” if you have decimal measuring tools.
Draw that radius from horizontal to vertical. Every 1/2” measured along that radius is equal to 1 degree. What I did next was layout 10 degrees, measure that distance with dividers and then walk the dividers to the vertical line and see how close I came. Once I had the radius divided into 9 equal spaces they were divided in half and then all the 1 degree marks are added. And of course every 1/8” along the arc is 1/4 of a degree. I never felt it was necessary it add that till I needed it.
I often thought that a vertical and horizontal dado for a miter gauge bar would be handy for setting the miter gauge,but I never did it.
Hopefully this information is useful to someone and feel free to ask questions if you have them. This is just the first installment on the different ways I handle angles and bevels.
-- Jim, Long Island, NY Ancorayachtservice.com home of the chain leg vise