ANSI and ISO insert designations

External Turning Tools

Indexable inserts of cutting tools are standardized and designated with letters and digitals. This significantly eases management and production. The industry has two major designation systems, e.g., metric (ISO) and inch (ANSI). This article addresses the classification and differences between ISO and ANSI cutting tools. The main distinction lies in the middle digits, and the representation of different tools also varies.

For example:

ISO: CNMG120408PS

ANSI: CNMG432PS

The first letter represents the shape of the insert, which is the same for metric and inch systems. H: hexagon 120°, O: octagon 135°, P: pentagon 108°, S: square 90°, T: triangle 60°, C: rhombus 80°, D: rhombus 55°, E: rhombus 75°, F: rhombus 50°, M: rhombus 86°, V: rhombus 35°, W: hexagon 80°, L: rectangle 90°, A: parallelogram 85°, B: parallelogram 82°, K: parallelogram 55°, R: round.

The second letter represents the relief angle of the insert, which is the same for both metric and inch systems. A: 3°, B: 5°, C: 7°, D: 15°, E: 20°, F: 25°, G: 30°, N: 0°, P: 11°.

The third letter represents the tolerance of the insert, which is the same for metric and inch systems and varies depending on the insert size.

The fourth letter represents the hole/chip breaker symbol. There are many types, but two common ones are mentioned: G for general external inserts with holes and double-sided chip breakers, and T for boring inserts with a single-blind hole and a single-sided chip breaker.

For the meanings of the third and fourth digits, you can refer to the sample of the tool you are using, as it will have explanations.

The above letter meanings apply to all turning inserts. From the fifth position onward, there are differences. Let’s start with ceramic, layered hard alloy, and hard alloy inserts:

The fifth digit represents the cutting-edge length in ISO and the inner corner radius in ANSI.

The sixth digit represents the thickness. In ISO, the unit is millimeters (mm), while in ANSI, it is inches.

The seventh digit represents the nose angle. In ISO, the unit is millimeters (mm), while in ANSI, it is inches.

The last two letters represent arbitrary symbols, such as the main cutting edge symbol, chip breaker symbol, etc.

In addition, there are additional numeric and alphabetic suffixes, such as VP15TF, which represent the material of the tool. Different brands may have different material codes for their tools.

There are also special marking methods, such as CCGT060201MER-U and CCGT060201MFP-GF.

M: Negative tolerance for the cutting-edge radius. (Usually, the radius of an insert is 0.4. When the part being machined requires a radius ≤0.2 in a specific area, an insert with a negative tolerance for the cutting edge radius is needed.)

E: Chamfer on the cutting edge.

F: Sharp cutting edge.

R: Right-hand direction of the insert.

P: Mirror-like surface of the insert.

U, GF: Both indicate chip breakers.

Next, let’s discuss ceramic inserts:

Unlike before, ceramic inserts do not indicate chip breaker type but specify the nose specification, such as CNGA120404S01525.

S01525 represents the nose specification.

S: Chamfer + honing. For example, S01525 means chamfer + honing of 0.15mm × 25°.

T: Chamfer. For example, T02025 means chamfer of 0.20mm × 25°.

Now, for polycrystalline diamond (PCD) inserts:

For example CNGA120404S01225ME

The nose angle is 0° (N), cutting edge length is 12 (12), 0.4 radius (04), 80° rhombus (C) insert. The insert has a chamfer + honing of 0.12mm × 25° (S01225) on the cutting edge. It is a small-sized insert, and its nose reinforcement is a standard specification insert (ME).

Apart from S and T, there is also E: honing, for example, E008R0.08mm honing.

All PCD inserts with additional symbols after the nose specification has shorter cutting-edge lengths and are small-sized inserts. Inserts without symbols are long, cutting-edge inserts. Additionally, including inserts without symbols, SE, and ME, the nose reinforcement of all these inserts is a standard specification. SET (SE-T) and MET (ME-T) are reinforced nose inserts, and BB1, BB2, and BB3 have chip breakers.

There are also groove-cutting inserts and cutoff inserts, but the standards for these are not unified, and different brands have their own designations. For example, GB43R150 PR930 is a type of groove-cutting insert. R indicates a right-hand insert, 150 indicates a blade width of 1.5, and PR930 indicates the material of the insert. For groove-cutting and cutoff inserts, you can only refer to the tool sample, as there is no other way to determine their specifications.

Thread inserts: 16ER100ISO-TF

16 represents the insert size (16: 9.525, 22: 12.70), E distinguishes between internal and external threads (E for external threads, I for internal threads), R indicates the insert direction (R: right-hand, L: left-hand), 100 represents the pitch or number of teeth (this varies between metric and inch systems; for metric threads, 100 represents a pitch of 1mm, 150 represents a pitch of 1.5mm; for inch threads, 24 represents 24 teeth per inch, and 20 represents 20 teeth per inch), ISO indicates the thread type (ISO, M: metric threads, UN: unified threads, W: Whitworth threads, BSPT: tapered pipe threads, NPT: National Pipe Taper threads), TF indicates the cutting edge style. There are also TS (TS chip breakers) and M02 (2-tooth chip breakers). All the threads, as mentioned above inserts have a wiper facet. Now, let’s discuss thread cutoff inserts, which do not have a wiper facet.

For example 16ERA60-TF

16 represents the insert size (06: 3.97, 08: 4.76, 11: 6.35, 16: 9.525, 22: 12.70), E distinguishes between internal and external threads (E for external threads, I for internal threads), R indicates the insert direction (R: right-hand, L: left-hand), A60 represents the pitch or number of teeth (the number represents the top angle, divided into 60° and 55°, A60: 60° without a wiper facet, pitch ranging from 0.5mm to 1.5mm, G60: 60° without a wiper facet, pitch ranging from 1.75mm to 3mm, GA60: 60° without a wiper facet, pitch ranging from 0.5mm to 3mm.

A55: 55° without a wiper facet, number of teeth ranging from 40 to 16 per inch.

G55: 55° without a wiper facet, number of teeth ranging from 14 to 8 per inch.

GA55: 55° without a wiper facet, number of teeth ranging from 40 to 8 per inch.

In addition, it is also possible to write it as 6001 represents 60° without a wiper facet, nose radius of 0.1mm, pitch ranging from 1.0mm to 2.5mm; 5501 means 55° without a wiper facet, nose radius of 0.1mm, number of teeth ranging from 28 to 11 teeth per inch.

TF indicates the cutting-edge style, and there is also TS: T’s chip breakers.

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