Cutting Tool Insert

Cutting tool inserts are essential components in modern machining, enabling precision, efficiency, and versatility in metalworking operations. These inserts are replaceable cutting tips mounted on tool holders, designed for turning, milling, drilling, and other machining processes. To ensure compatibility and performance, a standardized insert designation system is used worldwide. Additionally, selecting inserts from reputable manufacturers guarantees quality and reliability.

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Cutting Tool Insert Designation: Decoding the System

The ISO 1832 standard is the most widely recognized system for classifying indexable inserts. It uses a series of letters and numbers to denote key characteristics such as shape, relief angle, tolerance, chipbreaker type, size, thickness, and corner radius .

Key Components of Insert Designation

1. Insert Shape (1st Character)
   • Represented by a letter (e.g., C, D, S, T).
   • Common shapes include: C (80° diamond), D (55° diamond), S (square), T (triangle), R (round) .
2. Clearance Angle (2nd Character) : Indicates the relief angle (e.g., N (0°), A (3°), B (5°), C (7°)) .
3. Tolerance Class (3rd Character) : Defines dimensional accuracy (e.g., E (±0.025mm), M (±0.05-0.15mm)) .
4. Type (4th Character – Hole & Chipbreaker) : Specifies hole type and chipbreaker geometry (e.g., G (hole + chipbreaker), N (no hole)) .
5. Size (5th Character – Inscribed Circle or Dimensions) : Given in eighths of an inch (e.g., 04 = 4/8″ or 12.7mm) .
6. Thickness (6th Character) : Measured in sixteenths of an inch (e.g., 03 = 3/16″ or 4.76mm) .
7. Corner Radius (7th Character) : Indicates nose radius (e.g., 04 = 0.4mm, 08 = 0.8mm) .
8. Cutting Edge Condition (8th Character) : Describes edge preparation (e.g., F (sharp), E (rounded), T (chamfered)) .
9. Optional Codes (10th+ Characters) : May include rake angle, special coatings, or wiper geometry .
10. Cutting Direction (9th Character) : R (right-hand), L (left-hand), N (neutral) .

1- Insert Shape

Code Letter	Description	Diagram	Nose Angle
A	85 parallelogram		85
B	82 parallelogram		82
C	80 diamond		80
D	55 diamond		55
E	75 diamond		75
H	hexagon		120
K	55 parallelogram		55
L	rectangle		90
M	86 diamond		86
N	55 parallelogram		55
O	octagon		135
P	pentagon		108
R	round		full radius
S	square		90
T	triangle		60
V	35 diamond		35
W	trigon		80
X	sp. parallelogram		85

2- Clearance or Relief Angle 

Code Letter	Angle	Diagram
N	0
A	3
B	5
C	7
P	11
D	15
E	20
F	25
G	30

3- Tolerance 

Code Letter	Cornerpoint (inches)	Thickness (inches)	Inscribed Circle (in)	Cornerpoint (mm)	Thickness (mm)	Inscribed Circle (mm)
A	.0002″	.001″	.001″	.005mm	.025mm	.025mm
C	.0005″	.001″	.001″	.013mm	.025mm	.025mm
E	.001″	.001″	.001″	.025mm	.025mm	.025mm
F	.0002″	.001″	.0005″	.005mm	.025mm	.013mm
G	.001″	.005″	.001″	.025mm	.13mm	.025mm
H	.0005″	.001″	.0005″	.013mm	.025mm	.013mm
J	.002″	.001″	.002-.005″	.005mm	.025mm	.05-.13mm
K	.0005″	.001″	.002-.005″	.013mm	.025mm	.05-.13mm
L	.001″	.001″	.002-.005″	.025mm	.025mm	.05-.13mm
M	.002-.005″	.005″	.002-.005″	.05-.13mm	.13mm	.05-.15mm
U	.005-.012″	.005″	.005-.010″	.06-.25mm	.13mm	.08-.25mm

4- Hole / Chipbreaker

Code Letter	Diagram	Hole	Hole Shape	Chipbreaker Type
Null		No		None
A		Yes	Cylindrical	None
B		Yes	70-90 double countersink	None
D		Yes	Cylindrical	None
E		No		None
F		No		Double-sided
G		Yes	Cylindrical	Double-sided
H		Yes	70-90 single countersink	Single-sided
M		Yes	Cylindrical, or dbl countersink	Single-sided
N		No		None
P		Yes	Cylindrical	Hi-double positive
Q		Yes	40-60 double countersink	None
R		No		Single-sided
S		Yes	Cylindrical	Hi-double positive
T		Yes	40-60 double countersink	Single-sided
U		Yes	40-60 double countersink	Double-sided
W		Yes	40-60 double countersink	None
Z		Yes	Cylindrical	Double-sided hi-double positive

5- Cutting Edge Condition

Code Letter	Edge Preparation	Diagram
F	sharp
E	honed
T	T-land
S	honed T-land
X	special chamfer

6- Wiper Clearance Angle

Code Letter	Angle
C	7
D	15
E	20
F	25-26
G	30
N	0
P	11

7- Designation example

For example, a CNMG120408 insert decodes as:

• C (80° diamond shape)
• N (0° clearance angle)
• M (tolerance class)
• G (hole with chipbreaker)
• 12 (12.7mm inscribed circle)
• 04 (4.76mm thickness)
• 08 (0.8mm nose radius) .

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Cutting Tool Insert Manufacturers

1. Sandvik Coromant : A global leader in metal cutting tools, known for innovation and high-performance inserts. Offers a wide range of carbide, ceramic, and CBN inserts .
2. Kennametal : Specializes in advanced materials and cutting solutions, including inserts for aerospace, automotive, and energy industries .
3. ISCAR (IMC Group) : Renowned for high-productivity inserts, particularly in turning, milling, and grooving applications .
4. Mitsubishi Materials : A Japanese manufacturer offering high-precision carbide and ceramic inserts for demanding machining tasks .
5. Seco Tools : Known for sustainable machining solutions and high-performance inserts, including Duratomic®-coated grades .

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Conclusion

Understanding cutting tool insert designation ensures optimal tool selection for machining operations. By following the ISO 1832 standard, manufacturers and machinists can decode insert specifications accurately. Additionally, sourcing inserts from top manufacturers like Sandvik, Kennametal, ISCAR, Mitsubishi, and Seco guarantees quality, durability, and machining efficiency.

For more details on insert specifications, refer to manufacturer catalogs or industry standards like ANSI B212.4-2002 .

Would you like recommendations for specific insert grades or applications? Let us know in the comments!