Mortising Chisels: Drilling a Square Hole | Tools4Wood
2020-1-24 · Invented in 1874 by Robert and Ralph Greenlee of the Greenlee Company, this bit is made of a four-sided square chisel with a drill bit in the middle, this bit is then fitted onto a bench-mortiser. This specialized mortise and tenon drill bits can dig and remove material whilst still ensuring that the edges are clean and perfectly straight.
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