Stabilized tap with air release

Claim 1

In a tap having cutting teeth adapted to cut threads into the cylindrical walls of a hole having a hole diameter, said tap having a generally cylindrical body, a rear end for insertion into a tap handle, and a forward end for insertion into a hole to be tapped, said tap having a progressively reduced diameter threaded chamfer region and said cutting teeth having a constant diameter, said tap having longitudinal flutes between sections of said cutting teeth, the improvement comprising: a cylindrical stabilizer at the forward end of said tap, said stabilizer having an axis co-linear with a longitudinal axis of the body of said tap and a flat circular face perpendicular to said longitudinal axis, the diameter of said stabilizer being less than said hole diameter such that said stabilizer has a close, but interference-free fit within said hole; and longitudinal groove in said stabilizer for releasing air, said grooves being continuous with said flutes and extending entirely through said stabilizer and forming a plurality of arcuate cut-outs on the periphery of said flat circular face, each of said arcuate cut-outs intercepting an arc of less than 40 degrees on the periphery of said flat circular face, whereby as the hole is tapped, air may be released through said arcuate cut-outs, through said grooves and thence through said flutes continuous with said grooves, and air pressure released in the hole.