초록 ▼

A hole-cutting device for attachment to a portable electric drill or similar rotating machine. The device has a cylindrical body with a rearward edge and a forward edge; a mounting plate is affixed across the rearward edge, and a series of chipper teeth are affixed about the forward edge. Each chipp

A hole-cutting device for attachment to a portable electric drill or similar rotating machine. The device has a cylindrical body with a rearward edge and a forward edge; a mounting plate is affixed across the rearward edge, and a series of chipper teeth are affixed about the forward edge. Each chipper tooth has a transverse cutting edge and a second cutting edge in substantial alignment with the wall of the cylinder, but alternate chipper teeth have second cutting edges displaced inwardly and outwardly from the cylindrical member.

대표청구항 ▼

[ What is claimed is:] [7.] A hole-cutting apparatus for attachment to a rotary power tool, comprising:a) a thin-walled cylindrical member having a predetermined diameter and length, and having a forward and rearward circular edge;b) a connecting plate affixed along said rearward edge and extending

[ What is claimed is:] [7.] A hole-cutting apparatus for attachment to a rotary power tool, comprising:a) a thin-walled cylindrical member having a predetermined diameter and length, and having a forward and rearward circular edge;b) a connecting plate affixed along said rearward edge and extending across a diameter of said rearward circular edge;c) a plurality of chipper teeth removably affixed to said cylindrical member in relatively equal spaced-apart relationship, all of said teeth having cutting edges projecting forwardly of said forward circular edge; each said chipper teeth comprising a transverse cutting edge of a length exceeding the thickness of said thin-walled cylindrical member, said transverse cutting edge substantially positioned over said forward circular edge; each of said chipper teeth further comprising a side cutting edge in spaced position relative to said thin-walled cylindrical member, said plurality of chipper teeth being alternately aligned to provide alternate side cutting edges radially inwardly spaced and outwardly spaced from said thin-walled cylindrical member.