(Labor-saving and precise) This professional mortising chisel is ideal for drilling square holes in wood with a mortiser or mortising attachment. And reduce the intensity Reduce the work of construction workers, speed up the construction speed, reduce construction costs for construction and installation. (How to do the work) The square drill into the drill hole through the rotating body, while the impact of the impact force is transmitted to the outer body, the grinding material round and square hole head wall, and the dirt is discharged from the air hose. the same. (6 Different Sizes) Supplied with 6 different sizes: 1/4 inch, 5/16 inch, 3/8 inch, 1/2 inch, 9/16 inch, 5/8 inch, suitable for opening various square holes. (Material) Made of steel, heat treatment, high hardness, sharp blade, Continuous, fast cuts, high efficiency. (Application) Adapts to all mortisers and drill bits. Square hole is mainly used for woodworking aspects. Attention: the chisel alone does not work in one