In this chapter we will describe the turning insert identification coding system.
- Click below to view the metric or inch version of the Identification code!
Insert geometry
The insert geometry is represented using letters of the alphabet. A wide range of geometries are listed as standard for example; triangle, square, round, polygon and rhombus.
Normal clearance
This is the symbol that represents the clearance angle of an insert. An insert with 0° clearance angle, which is shown by symbol N, is called a negative insert. An insert with a clearance angle other than 0° is called a positive insert. Many turning inserts have clearance angles shown by symbols P, C and N.
Tolerance class
The symbol that represents the tolerance class is determined by a combination of three tolerances; the nose height (m), inscribed circle (d) and thickness (s). To produce close tolerance inserts, grinding is necessary.
A- to J-class inserts maintain close tolerances by grinding. They are generally termed as G-class inserts.
K- to U-class inserts only have the bottom and top faces ground. These are generally termed as M-class inserts.
For turning operations, mainly G-class (sometimes J-class) or M-class inserts are used. Inserts with tolerance classes other than G, J and M are mostly used on face milling cutters.
Chip breaher and/or hole
This symbol represents whether or not the insert has a chip breaker. It also refers to whether the insert has a hole or not. A negative insert can have one-sided or double-sided chip breaker.
Meanwhile, a positive insert has only one-sided chip breaker.
Cutting edge length (metric), diameter of inscribed circle (inch)
For the inch coding method, the diameter of an inscribed circle is shown by a numerical symbol. For example, an inscribed circle of 3/8 inch (9.525mm) is represented by the symbol 3. An inscribed circle of 4/8 inch (12.70mm) is shown as 4.
However, for the metric coding, the diameter of an inscribed circle is represented by the cutting edge length using a two-digit number. Therefore, even if the inscribed circle is the same , the symbol for the cutting edge will vary.
Insert thickness
This symbol represents the actual thickness of the insert. It works on the same principle as that of the inscribed circle.
Corner radius (nose radius)
This represents the corner radius (nose radius) of an insert. It is standardized in intervals, for example after 0.4mm with intervals of 0.4mm, and after 4.0mm in intervals of 0.8mm.
Honing
Cemented carbide, coated carbide, cermet, ceramic and other hard material inserts have the cutting edge honed so as to prevent fracturing in the machining.
There are a number of different types of honing, for example "round" honing and "chamfer" honing. The type of honing employed is shown by the appropriate symbol. Cutting tool manufacturers amploy their own honing geometries (size and angle) according to insert grade and size. Generally the honing symbol is omitted from an identification code.
Hand
This symbol represents the direction in which the insert can machine. If the insert can be used for both left and right (thus neutral) then the symbol is generally omitted.
Chip breaker
Chip breakers play an important role in chip control. Cutting tool manufacturers employ their own breaker geometries and as such the symbol is optional.
Insert geometry
The insert geometry is represented using letters of the alphabet. A wide range of geometries are listed as standard for example; triangle, square, round, polygon and rhombus.
Normal clearance
This is the symbol that represents the clearance angle of an insert. An insert with 0° clearance angle, which is shown by symbol N, is called a negative insert. An insert with a clearance angle other than 0° is called a positive insert. Many turning inserts have clearance angles shown by symbols P, C and N.
Tolerance class
The symbol that represents the tolerance class is determined by a combination of three tolerances; the nose height (m), inscribed circle (d) and thickness (s). To produce close tolerance inserts, grinding is necessary.
A- to J-class inserts maintain close tolerances by grinding. They are generally termed as G-class inserts.
K- to U-class inserts only have the bottom and top faces ground. These are generally termed as M-class inserts.
For turning operations, mainly G-class (sometimes J-class) or M-class inserts are used. Inserts with tolerance classes other than G, J and M are mostly used on face milling cutters.
Chip breaher and/or hole
This symbol represents whether or not the insert has a chip breaker. It also refers to whether the insert has a hole or not. A negative insert can have one-sided or double-sided chip breaker.
Meanwhile, a positive insert has only one-sided chip breaker.
Cutting edge length (metric), diameter of inscribed circle (inch)
For the inch coding method, the diameter of an inscribed circle is shown by a numerical symbol. For example, an inscribed circle of 3/8 inch (9.525mm) is represented by the symbol 3. An inscribed circle of 4/8 inch (12.70mm) is shown as 4.
However, for the metric coding, the diameter of an inscribed circle is represented by the cutting edge length using a two-digit number. Therefore, even if the inscribed circle is the same, the symbol for the cutting edge will vary.
Insert thickness
This symbol represents the actual thickness of the insert. It works on the same principle as that of the inscribed circle.
Corner radius (nose radius)
This represents the corner radius (nose radius) of an insert. It is standardized in intervals, for example after 0.4mm with intervals of 0.4mm, and after 4.0mm in intervals of 0.8mm.
Honing
Cemented carbide, coated carbide, cermet, ceramic and other hard material inserts have the cutting edge honed so as to prevent fracturing in the machining.
There are a number of different types of honing, for example "round" honing and "chamfer" honing. The type of honing employed is shown by the appropriate symbol. Cutting tool manufacturers amploy their own honing geometries (size and angle) according to insert grade and size. Generally the honing symbol is omitted from an identification code.
Hand
This symbol represents the direction in which the insert can machine. If the insert can be used for both left and right (thus neutral) then the symbol is generally omitted.
Chip breaker
Chip breakers play an important role in chip control. Cutting tool manufacturers employ their own breaker geometries and as such the symbol is optional.