I downloaded a free set of plans for timber-framed sawhorses from Timberframe Headquarters.
The plans call for a curved cut-out on the bottom side of each base piece. I was thinking it was too much trouble to lay out and cut these, but I remembered some how-to from the boat-building books I read last year, and I decided I wanted to try laying out and fairing a curve.
First, I used a sector, story sticks, and my L-square to find and mark the middle of the base. The sector saved me from having to divide fractions.
I laid out the straight lines in accordance with the plans. The bottom of the piece is toward the camera. (I’m sorry the lines are a bit hard to see.)
The mid-line is extended up the side of the piece to the point indicated in the plans for the top of the curve.
I needed a flexible batten in order to lay out the curve. I had an ordinary wooden paint-stirrer from the hardware store of just the right length. It was too stiff, so I thinned it down with a block plane. It was tricky not to make it too thin and breakable. (The bit at the end is unthinned.)
I clamped wood scraps to the piece in positions to hold the flexible batten in the right place.
Then I put the batten in place. I had to fiddle around with the wood scraps to get the batten to lie just right.
I just ran my pencil along the batten and got a fair and smooth curve.
It worked great!