Reamer features which differ from each other in turn in a regular sequence such as cutting edges, chip breakers, chamfers, or flutes
Angle of Taper
The included angle of taper on a taper tool or taper shank
Angular Flute
A flute which forms a cutting face lying in a plane intersecting the reamer axis at an angle. It is unlike a helical flute in that it forms a cutting face which lies in a single plane
Arbor Hole
The central mounting hole in a Shell Reamer – typically tapered at 1/8" per foot
Axial Rake
The angle between the cutting face of a reamer and its axis, measured along the direction the tool moves. This applies only to cutting edges that are not helical or spiral.
Axial Relief
The relief measured in the axial direction between a plane perpendicular to the axis and the relieved surface
Axis
The imaginary straight line which forms the longitudinal centerline of a reamer, usually established by rotating the reamer between centers
The central portion of a reamer below the flutes which joins the lands
Core Diameter
The diameter at a given point along the axis of the largest circle which does not project into the flutes
Core Reamer
A roughing reamer with relatively few, deep wide flutes to provide ample room for chips in reaming cored holes
Cutter Sweep
The section removed by the milling cutter or grinding wheel in entering or leaving a flute
Drift
A flat tapered bar for forcing a taper shank out of its socket
Drift Slot
A slot through a socket at the small end of the tapered hole to receive a drift for forcing a taper shank out of the socket
Duplex Lead Reamer
A reamer with one or more flutes having a different lead than the other flutes. This produces a continuous change in flute spacing (e.g. Morse Taper Duplex)
Eccentric Relief
A convex relieved surface behind the cutting edge
Eccentricity
The amount by which the reamer's cutting surface is offset from its axis. It is usually defined as half the Total Indicator Variation (TIV).
End Cutting
A general term describing the extent to which a reamer cuts on the end. Four types are recognized:
Longitudinal channels formed in the body of the reamer to provide cutting edges, permit passage of chips and allow cutting fluid to reach the cutting edge
The axial position on a taper where the diameter is equal to the basic large end diameter of the specified taper
Grinding Recess
A clearance or undercut for the edge or corner of a grinding wheel, usually necessary at a change of diameter
Guide
A cylindrical portion following the flutes of a reamer to maintain alignment
Half-Round Reamer
A reamer with a transverse cross-section of approximately half a circle and having one cutting edge – sometimes referred to as a "D" reamer
Heel
The trailing edge of the land in direction of rotation for cutting
Helical Flute
A flute which is formed in a helical path around the axis of a reamer (sometimes called a "spiral flute")
Helical Rake
The angle at which a helical flute cutting edge meets the body of the reamer. This angle affects how the tool enters the material and removes chips.
Helix Angle
The angle formed by a helical flute as it wraps around the reamer. This angle affects chip removal and cutting smoothness.
Hook
A curved (concave) cutting face design that influences how aggressively a reamer cuts. The shape of the hook impacts chip flow and cutting performance, especially in softer materials.
Internal Center
A 60 degree countersink with clearance at the bottom, in one or both ends of a tool, which establishes the tool axis
Irregular Spacing
A deliberate variation from uniform spacing of the reamer cutting edges
The flattened end of a taper shank which fits a slot in the socket
Tang Drive
Two opposite parallel driving flats on the extreme end of a straight shank
Tangential Rake Angle
A technical angle measured at the outer edge of the cutting face, describing how curved the hooked surface is in relation to a line pointing outward from the tool center. It affects chip removal and cutting forces.
Taper Per Foot
The difference in diameter between two points 12 inches apart measured along the axis
Taper Shank
A shank made to fit a specified (conical) taper socket