Reamer Nomenclature
Nomenclature of Terms in Reaming
Actual Size - The actual measured diameter of a reamer, usually slightly larger than the nominal size to allow for wear
Alternate - 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
Axis - The imaginary straight line which forms the longitudinal centerline of a reamer, usually established by rotating the reamer between centers
Back Taper - A slight decrease in diameter, from front to back in the flute length of reamers
Barrel - See preferred term Body
Bell Mouth Hole - A hole which is larger in diameter at the start of the hole than at some distance beyond
Bevel - An unrelieved angular surface of revolution (not to be confused with chamfer)
Blade - A tooth or cutting element inserted in a reamer body; it may be adjustable and/or replaceable
Blending Radius - A relieved radius joining the chamfer and the periphery
Body -
1) The fluted full diameter portion of a reamer, inclusive of the chamfer, starting taper and bevel
2) The principal supporting member for a set of reamer blades, usually including the shank Burnishing Reamer - A finishing reamer intended to take a light scraping cut and impart a fine finish
Chambering Reamer - A reamer (usually one of a series) for forming a shell chamber, etc. Chamfer - The angular cutting portion at the entering end of a reamer (see also Secondary Chamfer)
Chamfer Angle - The angle between the axis and the cutting edge of the chamfer measured in an axial plane at the cutting edge
Chamfer Length - The length of the chamfer measured parallel to the axis at the cutting edge
Chamfer Relief Angle - See Relief
Chamfer Relief - See Relief
Chip Breakers - Notches or grooves in the cutting edge of some taper reamers designed to break the continuity of the chips
Circular Land - See preferred term Margin
Clearance - The space created by the relief behind the cutting edge or margin of a reamer Concentric/Concentricity - See preferred terms Total Indicator Variation and Relative Eccentricity to describe lack of concentricity between two or more reamer elements
Core - 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 roughening reamer with 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
Cutting Edge - The leading edge of the land in the direction of rotation for cutting
Cutting Face - The leading side of the land in the direction of rotation for cutting on which the chip impinges
Cutting Speed - The peripheral lineal speed resulting from rotation, usually expressed as surface feet per minute (sfm)
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
Eccentricity (with respect to the reamer axis) - One half the Total Indicator Variation (tiv). See Relative Eccentricity.
End Cutting - A general term describing the extent to which a reamer cuts on the end. Four types are recognized:
1) End Cutting on the chamfers only
2) 180 degrees End Cutting to the bottom of the flutes (Core Diameter)
3) 180 degrees End Cutting to the center hole or a specified diameter of circle
4) 180 degrees End Cutting to the center of reamer
External Center - The pointed end of a reamer; the included angle varies with manufacturing practice
Feed - The axial advance in inches per revolution of the reamer with respect to the workpiece Flutes - 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
Flute Length - The length of the flutes not including the cutter sweep
Fluted Chucking Reamer - See preferred term Chucking Reamer
Full Indicator Reading (fir) - See preferred term Total Indicator Variation (tiv)
Gage Line - 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 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
Heel - The trailing edge of the land in direction of rotation for cutting
Helical Flute - (sometimes called a “spiral flute”) A flute which is formed in a helical path around the axis of a reamer
Helical Flute Straight Flute - A flute which forms a cutting edge lying in an axial plane
Helix Angle - The angle which a helical cutting edge at a given point makes with an axial plane through the same point
Hook - See definition under Rake
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
Land - The section of the reamer between adjacent flutes
Land Width - The distance between the leading edge of the land and the heel measured at a right angle to the leading edge
Lead - See preferred term Starting Taper
Lead of Flute - The axial advance of a helical or spiral cutting edge in one turn around the reamer axis
Length - The dimension of any reamer element measured parallel to the reamer axis
Limits - The maximum and minimum values designated for a specific element
Line Reamer - A reamer used to ream two or more separated holes on the same axis Margin - The unrelieved part of the periphery of the land adjacent to the cutting edge Multiple Diameter Reamer - A reamer with two or more cutting diameters
Neck - A section of reduced diameter connecting shank to body, or connecting other portions of the reamer
Nominal Size - The designated basic size of a reamer
Notches - See preferred term Chip Breakers
Oil Grooves - Longitudinal straight or helical grooves in shank, guide, or pilot for lubrication or to carry cutting fluid to the cutting edges
Oil Holes - Holes through which a cutting fluid is fed to the cutting edges of a reamer
Overall Length - The extreme length of the complete reamer from end to end, but not including external centers or expansion screws
Periphery - The outside circumference of a reamer
Pilot - A cylindrical portion preceding the entering end of the reamer body to maintain alignment Pull Reamer - Reamers which are designed to be pulled through long holes (such as gun barrels) while reamer or workpiece is rotated
Radial Rake Angle - See definition under Rake
Radial Runout - The radial variation from a true circle which lies in the diametral plane and is concentric with the reamer axis. See term Total Indicator Variation
Rake - The angular relationship between the cutting face, or a tangent to the cutting face at a given point and a given reference plane or line
Axial Rake - Applies to angular (not helical or spiral) cutting faces. It is the angle between a plane containing the cutting face, or tangent to the cutting face at a given point, and the reamer axis Helical Rake - Applies to helical and spiral cutting faces only, (not angular). It is the angle between a plane tangent to the cutting face at a given point on the cutting edge, and the reamer axis
Hook - A concave condition of a cutting face. The rake of a hooked cutting face must be determined at a given point
Negative Rake - Describes a cutting face in rotation whose cutting edge lags the surface of the cutting face
Positive Rake - Describes a cutting face in rotation whose cutting edge leads the surface of the cutting face
Radial Rake Angle - The angle in a transverse plane between a straight cutting face and a radial line passing through the cutting edge
Tangential Rake Angle - The angle in a transverse plane between a line tangent to a hooked cutting face at the peripheral cutting edge and a radial line passing through this point of tangency Recess - See preferred term Grinding Recess
Relief - The result of the removal of tool material behind or adjacent to the cutting edge to provide clearance and prevent rubbing (heel dragging)
Axial Relief - The relief measured in the axial direction between a plane perpendicular to the axis and the relieved surface. It can be measured by the amount of indicator drop at a given radius in a given amount of angular rotation
Back-Off - See preferred term Relief
Cam Relief - The relief from the cutting edge to the heel of the land produced by cam action
Chamfer Relief - The axial relief on the chamfer of the reamer
Chamfer Relief Angle - The axial relief angle at the outer corner of the chamfer. It is measured by projection into a plane tangent to the periphery at the outer corner of the chamfer
Eccentric Relief - A convex relieved surface behind the cutting edge
End Relief - See preferred term Axial Relief
Flat Relief - A relieved surface behind the cutting edge which is essentially flat
Primary Relief - The relief immediately behind the cutting edge or margin, properly called Relief Relief Angle - The angle, measured in a transverse plane, between the relieved surface and a plane tangent to the periphery at the cutting edge
Radial Relief - Relief in a radial direction measured in the plane of rotation. It can be measured by the amount of indicator drop at a given radius in a given amount of angular rotation
Secondary Relief - An additional relief behind the primary relief
Relative Eccentricity - The distance between the axis of one portion and the axis of some other portion of a reamer
Rose Reamer - A type of reamer with lands which are not relieved on the periphery. It has a relatively large amount of back taper
Runout - See Radial Runout
Salvage Hole - A central hole in the front end of a reamer of sufficient depth to provide for reconditioning
Secondary Chamfer - A slight relieved chamfer adjacent to and following the initial chamfer on a reamer
Shank - The portion of the reamer by which it is held and driven
Size - See terms Actual Size and Normal Size
Sleeve - A tapered shell designed to fit into a specified socket and to receive a taper shank smaller than the socket
Socket - The tapered hole in a spindle, adaptor or sleeve, designed to receive, hold, and drive a tapered shank
Spiral Flute - On a taper reamer, a flute of constant lead
Squared Shank - A cylindrical shank having a driving square on the back end
Staggered Flutes - See preferred term Irregular Spacing
Starting Radius - A relieved radius at the entering end of a reamer in place of a chamfer
Starting Taper - A slight relieved taper on the front end of a reamer
Step Reamer - A multiple diameter reamer with all lands in each step ground to the same diameter
Straight Shank - A cylindrical shank
Straight Flute - see Flutes
Subland Reamer - A type of multiple diameter reamer which has independent sets of lands in the same body section for each diameter
Tang - 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
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 Taper Square Shank - A taper shank whose cross section is a square Tongue - See preferred term Tang
Total Indicator Reading (tir) - See preferred term Total Indicator Variation (tiv)
Total Indicator Variation (tiv) - The difference between the maximum and minimum indicator readings obtained during a checking cycle
Undercut - See preferred term Grinding Recess