Insert DesignationsCarbide inserts use a coding system of numbers and letters to describe their shape, dimensions, and important parameters. For example, the designation of the insert shown in Figures 11-16 is aCNMG-433.

Figure 17: Carbide Insert Designation

Shape (CNMG-433)There are at least 18 different shapes of carbide inserts. The most commonly used are shown in Table 8.1 with their letter designation. The angle in this designation refers to the included nose angle at the cutting radius of the tool.Table 8.1: Common Insert Shape Codes

DesignationShape

TTriangle

SSquare

C80 degree diamond

D55 degree diamond

V35 degree diamond

RRound

Clearance Angle (CNMG-433)Clearance angle is the draft on the face(s) of the insert that contact material during machining. More about insert angles a little later.Table 8.2: Common Insert Clearance Angles

DesignationClearance Angle

N0 Degrees (No Draft)

A3 Degrees

B5 Degrees

C7 Degrees

P11 Degrees

Tolerance (CNMG-433)This is how much variation is allowed in the dimensional size of the insert. Tolerances described with this parameter include the corner point (nose radius), thickness, and I.C. Typical tolerances are shown in Table 8.3:Table 8.3: Typical Insert Tolerances (Inch)

DesignationCornerpointThicknessI.C.

M.002-.005.005.002-.005

G.001.005.001

E.001.001.001

K.0005.001.002-.005

Hole/Chip Breaker (CNMG-433)The hole/chip breaker designation describes both features with one letter. The hole in the insert and tool holder must match. If no letter exists in this field, then the insert does not have a hole to secure it to the holder, and is held by clamp force only.Table 8.4: Common Insert Hole/Chip Breaker Configurations

DesignationHole ShapeChipbreaker Type

GCylindricalSingle-sided

W40-60 deg, double c-sinkNone

RNoneSingle-sided

T40-60 deg, double c-sinkSingle-sided

PCylindricalHi-double positive

ZCylindricalHi-double positive

I.C. Size (CNMG-433)Inserts are measured by the diameter of an inscribed circle. I.C.'s range from .0625 in to 1.25 in. Table 8.5 lists the sizes you are most likely to use.Table 8.5: Common Inscribed Circle Sizes

DesignationDecimal (inch)Fractional (inch)

3.3753/8

4.5001/2

Thickness (CNMG-433)Insert thickness.Table 8.6: Common Insert Thickness

DesignationDecimal (inch)Fractional (inch)

3.1873/16

4.2501/4

Nose Radius (CNMG-433)Insert cutting nose radius.Table 8.7: Common Cutting Nose Radius

DesignationDecimal (inch)Fractional (inch)

1.0161/64

2.0311/32

3.0473/64

The insert shapes, sizes, and designations in these tables are just of few of what is available. Any lathe tool catalog or manufacturers web site will show many more.It is not important to memorize every tool shape or designation scheme. It is important to know insert terms and specifications to understand insert recommendations from the tool representative or technical resource to select the correct insert for the application.

MCLN R/L for Negative 80 CNM_ Inserts

MCMN N for Negative 80 CNM_ Inserts

MCRN R/L for Negative 80 CNM_ Inserts

MCKN R/L for Negative 55 DNM_ Inserts

MDJN R/L for Negative 55 DNM_ Inserts

MDPN N for Negative 55 DNM_ Inserts

MRGN R/L for Negative RNM_ Inserts

MSDN N for Negative SNM_ Inserts

MSKN R/L for Negative SNM_ Inserts

MSRN R/L for Negative SNM_ Inserts

MSSN R/L for Negative SNM_ Inserts

MTEN N for Negative 60 TNM_ Inserts

MTFN R/L for Negative 60 TNM_ Inserts

MTGN R/L for Negative 60 TNM_ Inserts

MTJN R/L for Negative 60 TNM_ Inserts

MVJN R/L for Negative 35 VNM_ Inserts

MVVN N for Negative 35 VNM_ Inserts

MWLN R/L for Negative 80 WNM_ Inserts

SCLC R/L for Positive 80 CCMT Inserts

SCMC N for Positive 80 CCMT Inserts

SDJC R/L for Positive 55 DCMT Inserts

SDPC N for Positive 55 DCMT Inserts

SSDC N for Positive SCMT Inserts

STEC N for Positive 60 TCxx Inserts

STFC R/L for Positive 60 TCxx Inserts

STGC R/L for Positive 60 TCxx Inserts

STJC R/L for Positive 60 TCxx Inserts

SVJC R/L for Positive 35 VCxx Inserts

Mini Toolholder and Boring Bar Set