Session 2
Classification of cutting tools
Geometry of single point cutting tools
Systems of description of tool geometry conversion of tool
angles from one system to another
Classification of cutting tools
Classification of cutting tools
Cutting tools may be classified according to the number
of major cutting edges (points) involved as follows:
• Single point: e.g., turning tools, shaping, planning and
slotting tools and boring tools
Classification of cutting tools
• Double (two) point: e.g., drills
Classification of cutting tools
• Multipoint (more than two): e.g., milling cutters,
broaching tools, hobs, gear shaping cutters etc.
Types of Tools
Single Point
Multipoint
Single point cutting tool
• The single point cutting tool has only one cutting point or
edge.
• These tools used for turning, boring, shaping or planning
operations.
• These tools used on lathe, boring and shaper machines.
• A single point cutting tool consists of sharpened cutting part /
operating end called as point and shank/ body.
• Point of tool is bounded by Face, side/major flank, end/minor
flank & base.
• Side/ major cutting edge is formed by intersection of face &
side flank.
• End/ minor cutting edge is formed by
intersection of face & end flank.
• Chips are cut from w/p by side cutting edges.
• Point where end, side cutting edges meet is
called nose
• Shank: It is main body of tool.
• Flank: surface/ surfaces below & adjacent to
cutting edge is flank of tool.
• Face: Surface on which chip slides is called face
of tool.
• Nose: It is formed at junction of side & end
cutting edges. This junction/ nose has a curve of
small radius, know as nose radius.
• Cutting Edge: It is the edge on the face of the
tool which removes the material from the work
piece. The cutting edge consists of the side
cutting edge(major cutting edge) and cutting
edge(minor cutting edge) and the nose.
1.Side Cutting Edge Angle:
The angle between side cutting edge and the side of
the tool shank is called side cutting edge angle.
2.End Cutting Edge Angle:
The angle between the end cutting edge and a line
perpendicular to the shank of the tool shank is called end
cutting edge angle.
3. Side Relief Angle:
The angle between the portion of the side flank
immediately below the side cutting edge and a line
perpendicular to the base of the tool.
4.End Relief Angle:
The angle between the end flank and the line
perpendicular to the base of the tool is called end relief
angle.
5.Back Rake Angle:
The angle between the face of the tool and line
perpendicular to the base of the tool measures on
perpendicular plane through the side cutting edge.
6.Side Rake Angle:
The angle between the face of the tool and a line parallel
to the base of the tool measured on plane perpendicular
to the base and the side edge.
Purposes of conversion of tool angles from one system to
another
To understand the actual tool geometry in any system
of choice or convenience from the geometry of a tool
expressed in any other systems
To derive the benefits of the various systems of tool
designation as and when required
Communication of the same tool geometry between
people following different tool designation systems.
Methods of conversion of tool angles from one system to
another
•Analytical (geometrical) method: simple but tedious
• Graphical method – Master line principle: simple, quick and
popular
• Transformation matrix method: suitable for complex tool
geometry
• Vector method: very easy and quick but needs concept of
vectors
Graphical method
This convenient and popular method of conversion of tool
angles from ASA to ORS and vice-versa is based on use of
Master lines (ML) for the rake surface and the clearance
surfaces.
Graphical method
This convenient and popular method of conversion of tool
angles from ASA to ORS and vice-versa is based on use of
Master lines (ML) for the rake surface and the clearance
surfaces.
Quiz Test
Select the correct answer from the given four options :
1. Back rake of a turning tool is measured on its
(a) machine longitudinal plane
(b) machine transverse plane
(c) orthogonal plane
(d) normal plane
2. A cutting tool can never have its
(a) rake angle – positive
(b) rake angle – negative
(c) clearance angle – positive
(d) clearance angle – negative
3. Inclination angle of a turning tool is measured on its
(a) reference plane
(b) cutting plane
(c) orthogonal plane
(d) normal plane
Questions
1. How is cutting tools classified?
2. Describe the geometry of single point cutting tools?
3. Explain the procedure of conversion of tool angles by
graphical method?