In woodworking parlance, it is a bar or board used to flatten out multiple
workpieces in relation to each other when clamping for a glue-up.
They sometimes have a slightly curved edge in order to exert more pressure
on the pieces being glued, and are often clamped to the work surface.
IOW, say you have a large panel glue-up and the pressure of the clamps
causes the panel to bow up in the middle. You would place a caul across the
workpiece and clamp said caul to the work table on both ends, thereby
flattening the bow and insuring a flat panel when the glue is dry.
There are other meanings of the word, and there might be an alternative
spelling, but the above is the one you will run across most in ww circles,
at least in my experience.
Last update: 9/21/03
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