Means and method for lubricating core drills

A core drill for drilling a chamfered hole in an article, comprising:

• a body having an inner bore, outer and inner drilling surfaces, and a chamfering surface;
• first means for diverting a first portion of a lucricating/cooling fluid from said inner bore to said inner drilling surfaces to lubricate and cool said inner drilling surfaces and the article portion being drilled and chamfered;
• and
• second means for diverting a second portion of the lubricating/cooling fluid from said inner bore to said chamfering surface and outer drilling surface to lubricate and cool the chamfering and outer drilling surfaces and the article portion being drilled and chamfered to at least minimize thermal damage to the article.

In a core drill having an inner bore, an inner chamber fluidly connected to the inner bore, chamfering, and inner and outer drilling surfaces, for drilling a chamfered hole in an article, a lubricating means for supplying the lubricating/cooling fluid to the chamfering and inner and outer drilling surfaces, comprising:

• (a) at least one channel provided through the core drill in fluid-delivering relationship to the chamfering and outer drilling surfaces;
• (b) an insert comprising:
• (i) a first portion having a longitudinal bore provided therethrough in fluid-receiving relationship to the inner bore of the core drill, and at least one transverse bore provided therethrough in fluid-receiving relationship to said longitudinal bore and in fluid-delivering relationship to said at least one channel, for delivering a first portion of the lubricating/cooling fluid to the chamfering and drilling surfaces, for lubricating/cooling the same;
• and
• (ii) a second portion, provided adjacent to said at least one transverse bore, comprising a longitudinal passageway of a diameter less than the diameter of said longitudinal bore of said first portion, disposed in fluid-receiving relationship to said longitudinal bore and in fluid-delivering relationship to the drilling surfaces for receiving a second portion of the lubricating/cooling fluid from said longitudinal bore, and for delivering said second portion to the drilling surfaces, for lubricating/cooling the same;
• (c) means for securably mounting said insert within the chamber of the core drill.