Terrific Shop Tips
Pinhole view puts flatness in focus
To check the surface of a panel for twists or warps, many woodworkers use winding sticks. You lay two straight-edged sticks on the panel and sight across the top edges of the sticks. If the panel isn't flat, the edges of the sticks won't appear to be parallel. I've used this method in the past, but as I've gotten older, my eyesight doesn't allow me to focus on both sticks at once.
To overcome this problem, I punch a small hole (less than 1/32") in a note card. Sighting through this "pinhole aperture," as shown, increases the depth of field and brings everything into clear focus. I use the same technique to sight along the edge of boards to check them for straightness.
-- Jeff Gaynor, Rootstown, Ohio
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