ISO. An international organization that establishes standards and guidelines for various products and processes. The International Organization for Standardization provides an alphanumeric labeling system for carbide cutting inserts to describe and organize their important characteristics.

A machining tool with excellent toughness, hardness, and wear resistance. Carbide cutting tools are made through compressing carbide with a binder, then heating the part to create a finished cutting tool.

The incline of the face of the cutting tool in relation to the workpiece. The rake controls the degree of cutting forces and cutting edge strength.

- DC: 55° rhombic shape with a positive rake angle. Suitable for finishing to medium operations with low cutting forces and good chip control.

A specialized triangular cutting point geometry. Wipers can improve surface finish, extend tool service life, and increase cutting efficiency.

A machine tool that is used to produce a range of cylindrical workpieces. On a basic lathe, the part is rotated in a spindle while a single-point tool is guided along its exterior to shape the part or into the workpiece to create grooves or threads.

- CC: 80° rhombic shape with a positive rake angle. Suitable for finishing to medium operations with low cutting forces and good chip control.

A triangular cutting insert with 80° included angles. Type-W inserts, also known as trigon inserts, are less versatile than triangle inserts but offer better cutting edge strength.

A stated measurement that may not correlate exactly with a physical part. Nominal measurements for an insert indicate size specified in the blueprint, which will differ from the size of the actual part.

An indexable cutting tool with four equal sides that create two 35° angles at the cutting edges. A 35° diamond insert, also known as a Type-V insert, has the lowest cutting edge strength but creates the most precise and intricate cuts.

The angle created between the facet and the workpiece. The smaller the face clearance, the closer the facet is to the workpiece.

A threaded device used for fastening parts. A screw may be used to more securely hold a cutting insert with a countersink.

An indexable cutting tool that has four equal sides that meet at 90° angles. Type-S inserts, also known as square inserts, offer a good balance of edge strength and reduced risk of tool chatter.

The measurement of the wideness of an insert when viewing it from the side. Thickness is described by the cutting insert number.

A feature or device designed to prevent chips from forming into long pieces. Chipbreakers are either molded features on the surface of the cutting insert or wafers clamped above the insert in the toolholder.

Containing both letters and numbers. Alphanumeric labels are used by both ANSI and ISO to categorize carbide cutting tools.

The degree of roundness between two cutting edges of a tool. The greater the nose radius, the greater the roundness of the tip, which leads to greater metal removal rate but also increased tool chatter.

The various stresses involved in a machining process. Cutting forces are determined by a combination of speed and feed rate, tool angle, workpiece material, and other factors.

An indexable carbide cutting tool primarily used for roughing operations. Utility inserts generally have looser tolerances than precision inserts.

A cut made in a cylindrical workpiece that leaves a narrow section of the workpiece connected to the larger piece at a series of 90° angles. Square shoulders can only be cut using inserts with smaller included angles such as diamond or triangular inserts.

A tool that has its major cutting edge on the left side of the insert when viewed from the end of the workpiece looking toward the cutting tool. Left-handed tools are indicated by an "L" as the ninth character in the ANSI insert number system.

A specific naming or numbering system used to logically categorize items. Nomenclature describes the use of number and letter designations to categorize and classify the properties of a tool.

A tool that can be used to cut from the left, the right, or from a position directly above the centerline of the workpiece. Neutral tools are indicated by an "N" as the ninth character in the ANSI insert number system.

The size of a lathe inserts refers to the length of its cutting edge (L) and its inscribed circle diameter (IC), which determine its strength and rigidity. The size of a lathe bit should be chosen according to the maximum cutting depth (ap) and the required cutting length (LE) of the operation, as well as the tool holder's clearance angle, the workpiece diameter, and the machine specifications. The size of a lathe bit should be as large as possible to ensure high stability and productivity.

Vibrations of the cutting tool that cause surface imperfections on the workpiece. Tool chatter is more common when using inserts with larger included angles such as round inserts.

- SC: 90° square shape with a positive rake angle. Suitable for finishing to medium operations with low cutting forces and good versatility.

ANSI Insert Selection provides information on how to identify the qualities and properties of a carbide cutting insert based on its ANSI insert number. Carbide inserts are the most commonly used tools for metal cutting and are manufactured in a variety of types that are optimized for different applications. By learning the ANSI insert nomenclature, users can identify insert shape, clearance angle, tolerance, type, size, thickness, and cutting point among other important features. These features dictate the capabilities and ideal uses of the insert.Users who understand ANSI insert nomenclature can select and order the optimal cutting insert for any given cutting process. Proper tool selection determines part quality, production rate, and tool life and is an essential component in ensuring the efficiency, cost-effectiveness, and quality of a manufacturing application.

A solid tool with specific features formed by pressing and heating powdered material. Chipbreakers are among the features that can be built into sintered cutting inserts.

The description of the features present on an indexable carbide cutting insert. Insert type, also known as insert style, is defined by the presence or absence of features such as holes, countersinks, and chipbreakers.

An unwanted but acceptable deviation from a given dimension defined by a blueprint. Tolerance of a carbide insert is one of the factors described by an insert number.

A cutting pass that emphasizes high material removal rate over the quality of surface finish or accuracy. Roughing is often performed using inserts with less exact tolerances.

The flat surface on a carbide cutting insert facing away from the toolholder. Tool face indicates the large surface right above the cutting edge.

A cutting insert with three equal sides that create three equal angles. Triangle inserts, also known as Type-T inserts, are considered the best general-purpose inserts.

A parallelogram cutting insert with 85° included angles. Type-A inserts have the strongest cutting edges of all parallelogram inserts.

A cutting tool with multiple cutting edges that can be rotated into place. Indexable inserts can be turned to expose a new cutting edge when one cutting edge wears out.

The process of machining tapered, contoured, or curved surfaces. Profiling requires the use of cutting inserts with smaller included angles.

A machining operation performed on the lathe that cuts a narrow channel into a rotating cylindrical workpiece. Grooving is often done with rectangle or parallelogram inserts.

An indexable cutting insert featuring opposite sides that are equal and parallel and come together at 90° angles. Type-L inserts, also known as rectangle inserts, are often used in milling cutters.

- TN: 60° triangular shape with a negative rake angle. Suitable for finishing operations with low cutting forces and good surface quality.

A machining operation where a single-point cutting tool is guided along the length of a rotating cylindrical workpiece. Turning is often performed with trigon, diamond, or triangle cutting inserts.

- TC: 60° triangular shape with a positive rake angle. Suitable for finishing operations with low cutting forces and good surface quality.

Machined with an abrasive to achieve accurate dimensions. Inserts that have been ground on all faces have tighter tolerances than those ground on just two faces.

A shearing operation that performs a single cut in order to separate a piece of metal from the original stock. Cutoff operations are often done with tools featuring a rectangle or parallelogram cutting insert.

A letter and/or number designation that indicates the specific chemical and material composition for a particular carbide cutting tool or indicates how that tool should be used. Grade is highly variable between manufacturers and any broad classification system can only be used as a general guideline.

American National Standards Institute. A private, nonprofit organization that administers and coordinates voluntary standards and systems. ANSI provides a classification system for carbide cutting tools using an alphanumeric label that details characteristics such as size, shape, and tolerance.

The distance between the bottom of the cut and the uncut surface of the workpiece. Depth of cut determines how much material is removed with a single pass of the tool.

An indexable insert with eight equal sides that form 135° angles. Octagon inserts, also known as Type-O inserts, have good cutting edge strength but can only be used in limited applications.

The length of time a cutting tool is expected to be operational before it must be replaced. A carbide cutting tool has a long service life.

A machining process that uses a tool to remove metal from a workpiece. Metal cutting processes include drilling, turning, and milling.

An indexable cutting tool with four equal sides that create two 55° angles at the cutting edges. Type-D cutting inserts, also known as 55° diamond inserts, have low cutting edge strength but are essential for precise cutting operations such as tracing.

The description of the features present on an indexable cutting insert. Insert style, also known as insert type, is defined by the presence or absence of features such as holes, countersinks, and chipbreakers.

International Organization for Standardization. An international organization that establishes standards and guidelines for various products and processes. The ISO provides an alphanumeric labeling system for carbide cutting inserts to describe and organize their important characteristics.

A series of numbers and/or letters used to describe a cutting tool insert. The part number, also known as an insert number or product number, usually refers to the ANSI insert identification number, but it can also refer to the ISO insert identification number.

The edge of the insert that performs the actual cut or the corner of the cutting edge that is in contact with the workpiece. The shape of the cutting point determines factors such as the strength of the insert, finish quality, and effective depth of cut.

A removable, geometric cutting bit that has multiple cutting edges. Cutting inserts are classified by grades and insert numbers.

IC. A circle that fits exactly within the boundaries of another shape. An inscribed circle is used to measure the overall size of a carbide insert.

An indexable cutting tool with four equal sides that create two 35° angles at the cutting edges. Type-V inserts, also known as 35° diamond inserts, have the lowest cutting edge strength but create the most precise and intricate cuts.

A small, flat surface next to the cutting point. A facet affects the amount of insert contact with the workpiece behind the action of the cutting edge.

An insert feature designed to prevent chips from forming into long pieces. Chipbreakers are either molded features on the surface of the cutting insert or a wafer clamped above the insert in the toolholder.

- CN: 80° rhombic shape with a negative rake angle. Suitable for roughing operations with high cutting forces and stability.

An indexable cutting insert with six equal sides that form 120° angles. Type-H inserts, also known as hexagon inserts, have good cutting edge strength but can only be used at positive lead angles, which can limit their use.

An alloy of iron and carbon containing less than 2.0% carbon. Steel machined at high speeds can form long chips that can damage metal cutting equipment.

An indexable cutting insert featuring opposite sides that are equal and parallel and come together at 90° angles. Rectangle inserts, also known as Type-L inserts, are often used in milling cutters.

An interior beveled surface that provides room for the head of a screw. Countersinks in inserts allow screws to sit flush with the insert surface.

A multi-point cutting tool that has teeth around its cutting edge. Milling cutters often have rectangle or parallelogram inserts as their cutting teeth.

The angle formed by the line of the side flank and the line of the surface with which the tool is engaged. End cutting edge angle affects cutting edge strength; the greater the end cutting edge angle, the weaker the cutting edge.

A parallelogram cutting insert with 55° included angles. Type-K inserts have the second weakest cutting edges of all inserts but are very precise.

The erosion of material as a result of friction. Wear can be prevented or reduced by using cutting inserts with good edge strength.

A cutting insert with three equal sides that create three equal angles. Type-T inserts, also known as triangle inserts, are considered the most versatile of all cutting inserts.

A circular indexable cutting tool. Type-R inserts, also known as round inserts, have the greatest edge strength but the highest risk of tool chatter.

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Lathe inserts are cutting tools that are used to shape metal, wood, plastic, or other materials on a lathe. Lathe inserts come in various shapes, sizes, and materials, depending on the type of workpiece and the desired finish.

The rate at which the cutting tool and/or the workpiece move in relation to one another. Feed is often measured in inches per minute (ipm) or millimeters per minute (mm/min).

The corner radius of a lathe bit refers to the curvature of its cutting edge at the corner (RE), which affects its edge strength, surface finish, and chip formation. The corner radius of a lathe bit should be chosen according to the machining parameters (ap, fn) and the workpiece material properties. The corner radius of a lathe bit should be as large as possible to ensure high edge strength and durability, but not too large to cause excessive heat generation or chip jamming.

An indexable cutting tool that has four equal sides that create four 80° angles. Type-C inserts, also known as 80° diamond inserts, are used for a wide range of operations, such as facing and turning, but are not as precise as diamonds with smaller included angles.

A plain carbon steel that contains less than 0.30% carbon. Low-carbon steels are ductile and prone to forming long, stringy chips.

An indexable cutting insert with six equal sides that form 120° angles. Hexagon inserts, also known as Type-H inserts, have good cutting edge strength but can only be used at positive lead angles, which can limit their use.

A part that is subjected to a manufacturing process such as metal cutting or welding. A workpiece is any metal that is cut to create a finished product.

Any fluid used to cool, lubricate, and clear chips during metal cutting. A cutting fluid can be oil- or water-based liquid, gas, or paste.

- DN: 55° rhombic shape with a negative rake angle. Suitable for medium to roughing operations with good chip control and edge strength.

The breaking of a tool into two or more pieces as a result of stress. Tool fracture is common in cutting inserts that have low edge strength, such as 55° parallelogram or 35° diamond inserts.

A triangular cutting insert with 80° included angles. Trigon inserts, also known as Type-W inserts, are less versatile than triangle inserts but offer better cutting edge strength.

The classification of a carbide cutting tool related to the presence or absence of chipbreakers, countersinks, and holes. Insert type is described by the insert number of a tool.

Machining metals at moderate speeds and feeds. Medium machining can be performed with inserts that have chipbreakers on both sides.

A threaded device used for fastening parts. A screw may be used to more securely hold a cutting insert with a hole and a countersink.

The process of cutting a spiraling groove into a cylindrical workpiece. Threading is often done with rectangle or parallelogram inserts.

A machining operation that uses a multi-point horizontal or vertical cutter to remove metal from the surface of the workpiece. Milling is often performed with cutting tools that have parallelogram cutting inserts.

An indexable cutting insert with two sets of opposite sides that are equal and parallel. Parallelogram inserts are often used in milling cutters and common versions come with included angles measuring 85°, 82°, and 55 degrees.

Inscribed circle. A circle that fits exactly within the boundaries of another shape. An inscribed circle is used to measure the overall shape of a carbide insert.

The angle from which a cutting tool must approach the workpiece, based on the shape and design of the insert. Cutting tool direction can be described as right-handed, left-handed, or neutral.

An indexable cutting tool that has four equal sides that create four 80° angles. A 80° diamond insert, also known as a Type-C insert, is used for a wide range of operations, such as facing and turning, but is not as precise as diamond inserts with smaller included angles.

An angle formed by the end flank of the insert and the workpiece surface. Clearance angle helps determine the strength of the cutting edge and the quality of part finish.

A machining operation occurring under very high pressures or temperatures. Severe machining often requires the use of inserts that have chipbreakers sintered into one side.

The ability of a material to resist forces that attempt to break or deform it. Inserts with good strength can operate at higher feed rates and withstand tool wear.

The machining of easily cut metals at low speeds and light feeds. Light machining can be performed with inserts that have chipbreakers on both sides.

The angle created between the facet and the workpiece. The smaller the facet clearance, the closer the facet is to the workpiece.

An indexable cutting insert that has five equal sides that form 108° angles. Type-P inserts, also known as pentagon inserts, have excellent cutting edge strength but are prone to tool chatter.

A chip that easily fractures from the workpiece into small, separate pieces. A discontinuous chip is usually formed when machining brittle materials such as cast iron.

The rate at which a cutting edge of a tool moves past the workpiece surface at the point of contact. Speed is measured in revolutions per minute (rpm).

An indexable carbide cutting tool primarily used for finishing operations. Precision inserts have very tight tolerances.

An indexable cutting insert that has five equal sides that form 108° angles. Pentagon inserts, also known as Type-P inserts, have excellent cutting edge strength but are prone to tool chatter.

The geometry of a lathe inserts refers to the shape and angle of its cutting edge, which determines how it interacts with the workpiece and produces chips. The geometry of a lathe inserts can be classified into three types: fine, medium, and rough. Fine geometry is suitable for operations with low cutting depth and feed rate, where low cutting forces and high surface quality are required. Medium geometry is suitable for operations with moderate cutting depth and feed rate, where a balance between edge strength and chip control is needed. Rough geometry is suitable for operations with high cutting depth and feed rate, where high edge strength and chip removal are required.

ANSI. A private, nonprofit organization that administers and coordinates voluntary standards and systems. The American National Standards Institute provides a classification system for carbide cutting tools using an alphanumeric label that details characteristics such as size, shape, and tolerance.

A cutting tool that has a single cutting edge. Single-point cutting tools are used in manufacturing applications such as turning.

An indexable cutting tool that has four equal sides that meet at 90° angles. Square inserts, also known as Type-S inserts, offer a good balance of edge strength and reduced risk of tool chatter.

An angled surface similar to a chamfer created by milling or turning. Shoulders are often created using a triangle cutting insert.

Ground to have an exceptionally smooth surface quality. A polished edge is machined to have a surface that is smooth up to a 4 microinch (µin), or 0.10 micrometer (µm), magnification.

A circular indexable cutting tool. Round inserts, also known as Type-R inserts, have the greatest edge strength but the highest risk of tool chatter.

A cutting operation that involves making very shallow cuts into a workpiece. Tracing is done with precise cutting inserts such as 35° diamond inserts.

The shape of a lathe inserts refers to the profile of its cutting edge, which determines its clearance angle and accessibility. The shape of a lathe inserts should be chosen according to the requirements of the tool holder and the workpiece geometry. The most common shapes of lathe inserts are:

An intersection of two lines or objects at a right angle. Perpendicular lines are used to determine several aspects of tool geometry, including rake angles.

A plain carbon steel that contains more than 0.45% carbon. High-carbon steel is extremely strong and hard, and it can require special insert preparation, such as chamfers, when being cut.

A line that extends from one edge of a circle to the opposite edge while intersecting the center. The diameter measurement is used to describe inscribed circles for carbide inserts under the ANSI system.

The corner of the insert where the cutting edges meet that is in contact with and cuts the workpiece. Cutting point shape determines factors such as the strength of the insert, surface finish quality, and effective depth of cut.

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The degree of roundness between the two cutting edges of a tool. Nose radius is described by the insert number and influences factors such as surface finish and insert strength.

A device used to hold a cutting tool in place during machining. A toolholder is designed to be paired with a few specific insert types.

A person trained to run a specific machine. Operators are responsible for helping ensure that a machining process runs properly, efficiently, and safely.

A series of numbers and/or letters used to describe a cutting tool insert. The insert number, also known as a part number or product number, usually refers to the ANSI insert identification number, but it can also refer to the ISO insert identification number.

The specifications created by ANSI to describe an indexable cutting insert using an alphanumeric label. The B212.4-1995 standard includes information about how to represent insert size, shape, and thickness, among other specifications, in the insert identification number.

A small wafer clamped onto the toolholder with the cutting insert to prevent long chips from forming. Mechanical chipbreakers are helpful when performing operations that remove large amounts of metal but make indexing a cutting tool more challenging.

The angle formed by the side flank of the tool and a line perpendicular to the workpiece centerline, if viewing a cutting tool from above. A positive lead angle moves the side flank into the cut, and a negative lead angle moves the side flank out of the cut.

A series of numbers and/or letters used to describe a cutting tool insert. The product number, also known as an insert number or part number, usually refers to the ANSI insert identification number, but it can also refer to the ISO insert identification number.

Choosing the right lathe bit for your project can make a big difference in the quality and efficiency of your machining process. By considering the factors discussed above, you can select the best lathe bit geometry, grade, shape, size, and corner radius for your specific application. If you need more guidance or advice , I'm always there for you.

An indexable insert with eight equal sides that form 135° angles. Type-O inserts, also known as octagon inserts, have good cutting edge strength but can only be used in limited applications.

A parallelogram cutting insert with 82° included angles. Type-B inserts have the second strongest cutting edges of all parallelogram inserts.

An angle formed by the end flank of the insert and the workpiece surface. Required clearance angle varies depending on the specific insert and application.

The leading face of a cutting tool that is in direct contact with the workpiece. The cutting edge performs the actual metal removal during a cutting operation.

An alloy of iron, carbon, and silicon that contains at least 2.0% carbon. Cast iron can be machined using round inserts because it is brittle and creates discontinuous chips.

The degree of roundness between two cutting edges of a tool. The nose radius is described by the insert number and influences factors such as surface finish and insert strength.

A flat surface of a single-point tool that is adjacent to the face of the tool. The side flank faces the direction that the tool is fed into the workpiece, and the end flank passes over the newly machined surface.

The grade of a lathe inserts refers to the material and coating of its cutting edge, which determines its wear resistance, toughness, and thermal conductivity. The grade of a lathe bit depends on the type of workpiece material (ISO P, M, K, N, S, H), the type of operation (fine, medium, rough), the machining conditions (good, average, difficult), and the lathe bit geometry. The grade of a lathe inserts should match the properties of the workpiece material and the machining parameters to ensure optimal performance and tool life.

The angle created between the primary cutting edge and the workpiece in the direction of the feed. Facet angle and facet clearance are described by two letters if the insert has a facet.

An angle describing the tilt of the tool face away from or toward the surface of the workpiece. A rake angle can be negative or positive.

A tool that has its major cutting edge on the right side of the insert when viewed from the end of the workpiece looking toward the cutting tool. Right-handed tools are indicated by an "R" as the ninth character in the ANSI insert number system.

An indexable cutting tool with four equal sides that create two 55° angles at the cutting edges. A 55° diamond insert, also known as a Type-D insert, has low cutting edge strength but is essential for precise cutting operations, such as tracing.

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A cutting operation where a tool is fed across the end of a cylindrical workpiece to create a flat surface and shorten its length. Facing is often done with diamond cutting inserts.

The slope of the flat edge directly adjacent to the cutting edge. A large facet angle decreases insert strength but increases its finishing ability.

The geometry of a lathe inserts can also be modified by adding a wiper feature, which is a small flat area on the cutting edge that improves the surface finish by smoothing out the tool marks. Wiper geometry can be used to achieve higher feed rates without compromising surface quality or to improve surface quality at standard feed rates.

IC. A circle that fits exactly within the boundaries of another shape. The inscribed circle of an insert touches all cutting edges and is an ANSI indicator for insert size.