Finding the center of a circle drawn on paper is quite easy using different drawing techniques. But when that circle is the face of a cylinder putting those drawing techniques into practice is quite complicated. With this trick we will be able to easily find the center of our cylindrical pieces of wood without even needing a ruler, a square or a compass.
The first thing I do is clamp a wood strip on the worktable. To do this I use a clamp in a way that I make sure that the clamp jaw that is on the wooden strip protrudes a few centimeters forward the edge of the strip.
This way I can rest my wooden cylinder against the wood strip and the clamp jaw serves as a stop.
Now I am going to put against the head of the cylinder a wooden block that is slightly thinner than half the diameter of the cylinder circumference.
I put a pencil on the thin block and I rotate the cylinder against the wood strip. Like this I can draw a circle on the end of the cylinder witch center is the center of the cylinder’s circumference.
If I move the pencil, approaching the center of the cylinder, I can draw smaller and smaller concentric circles.
The problem is that if the wooden block is too thin, the smallest diameter of the circle I can draw may be yet too large to approximate the center of the circumference easily. But by raising the pencil a little, putting something like a piece of folded sandpaper underneath, it is possible to make a circle so small that it will practically coincide with the center of the circumference of the wooden cylinder.