A router plane is a
hand plane
A hand plane is a tool for shaping wood using muscle power to force the cutting blade over the wood surface. Some rotary power planers are motorized power tools used for the same types of larger tasks, but are unsuitable for fine-scale planing, ...
used in
woodworking for smoothing out sunken panels, and more generally for all depressions below the general surface of the pattern.
It planes the bottoms of recesses to a uniform depth and can work into corners that otherwise can only be reached with a
chisel
A chisel is a tool with a characteristically shaped cutting edge (such that wood chisels have lent part of their name to a particular grind) of blade on its end, for carving or cutting a hard material such as wood, stone, or metal by hand, stru ...
.
Nowadays, it is largely supplanted by the
electrical router and
shaper, but retains limited application.
Further reading
References
Planes
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