A hole-saw comprises a tubular body connectable at one end to inter alia a power drill and formed at its other end with an annular array of cutting teeth. A collar is positioned at the end of the tubular body remote from the cutting teeth, the perimeter of the collar extending generally normal to and beyond the perimeter of the tubular body.

A cutting tool comprises a tool body having a first end and a second end, and a longitudinal axis extending between the first end and the second end. The first end comprises two or more cutting portions, with each of the cutting portions comprising a cutting edge and a flank surface.

Each cutting edge extends radially outwardly from a centre region of the first end to a perimetral edge of the first end, with the cutting edge being angled relative to the longitudinal axis. Each flank surface extends circumferentially from the cutting edge.

Each of at least two of the two or more flank surfaces comprises an abrasive portion extending over at least a part of the respective flank surface and each abrasive portion comprises a plurality of abrasive features.

One example of the present disclosure relates to a coupon. The coupon includes a first surface with a first circular channel and a second surface opposite and parallel to the first surface. The second surface is spaced a distance D0 from the first surface and includes a second circular channel concentric with the first circular channel. The coupon also includes a toroidal portion between the first circular channel and the second circular channel. The toroidal portion includes a rectangular sectional portion.

A core drill bit can include a first region and a second region. The first region can include abrasive particles in a first bond matrix, and the second region can include abrasive particles in a second bond matrix. The first region is connected to the second region. A composition of the first bond matrix can be different from a composition of the second matrix. In a particular embodiment, the first bond matric can include a Co-containing material.

One example of the present disclosure relates to a coupon. The coupon includes a first surface with a first circular channel and a second surface opposite and parallel to the first surface. The second surface is spaced a distance D0 from the first surface and includes a second circular channel concentric with the first circular channel. The coupon also includes a toroidal portion between the first circular channel and the second circular channel. The toroidal portion includes a rectangular sectional portion.

A rotary tool, in particular drilling tool, extends along a longitudinal axis and has an end surface; a brad point; and at least one major cutting edge extending outward up to an edge corner. A first free surface segment adjoins the major cutting edge, and a second free surface segment in turn adjoins said first free surface segment. To keep the stress, in particular the wear, low in the region of the end surface, the first free surface segment has a lower average abrasiveness than the second free surface segment.