Abstract: Disclosed are methods for applying durable markings to wearing surfaces, such as concrete factory floors, roadways, terrazzo or ceramic tile floors, or for imparting particular floor surface qualities, such as providing a non-skid surface. A diamond surface drill bit rotating at, for example, 2500 to 5000 rpm is employed to form dry recesses in the surface, which recess is immediately receptive to adhesive for attaching a premolded insert, or to an insert formed in situ, such as an insert of an acrylic polymer. The disclosed surface drill bit has a cutting end with two general types of diamond-impregnated cutting element segments attached. Attached around the periphery of the cutting end are peripheral gauge cutting element segments of arcuate configuration spaced from each other.

Abstract: Disclosed are methods for applying durable markings to wearing surfaces, such as concrete factory floors, roadways, terrazzo or ceramic tile floors, or for imparting particular floor surface qualities, such as providing a non-skid surface. A diamond surface drill bit rotating at, for example, 2500 to 5000 rpm is employed to form dry recesses in the surface, which recess is immediately receptive to adhesive for attaching a pre-molded insert, or to an insert formed in situ, such as an insert of an acrylic polymer. The disclosed surface drill bit has a cutting end with two general types of diamond-impregnated cutting element segments attached. Attached around the periphery of the cutting end are peripheral gauge cutting element segments of arcuate configuration spaced from each other.

Abstract: Disclosed is an improved core drill and a method of detachably coupling the same to a power driving unit to expedite the removal of a core therefrom. This is achieved by equipping the rear end of the drill stem with a fixedly attached externally threaded bushing. A coupling sleeve has internal threads at either end matable respectively with the bushing threads and the threaded drive shank of a power driving unit. This sleeve and the core drill are readily detached as a unit from the power drive thereby permitting the rapid removal of the core from the rear end of the drill rather than past the cutting ring at its front end.

Abstract: Disclosed is a core drill assembly and method of using the same to drill a countersunk hole through a concrete slab, wall or the like masonary member. The assembly utilizes concentric inner and outer core drills, the longer smaller one of which is provided with flushing fluid outlets rearwardly of the front end of the outer or countersink drill and provided with closure means for confining fluid flow to the inner drill when that drill is in use, and for diverting the flow to the outer drill while performing the countersink operation. The two drills have separate coupling facilities thereby permitting the substitution of drills of any selected relative sizes.

Abstract: A flame reactor burner is provided for reacting hydrogen and bromine to produce hydrogen bromide. Flame stability is enhanced by producing a helical flow of well mixed reactants within the burner, whereby the reactants in intimate contact with each other are propelled in an outward spiral path as they exit from the burner producing a hemispherical flame of high stability.