Milling Insert Designation Chart

 

Milling Insert Identification

Reference Guide

Milling Insert Designation Chart

A milling insert is identified by an eleven-position ANSI code. The first seven positions match the turning system; the last four describe wiper geometry, edge preparation, and cutting direction, which apply to milling inserts only. Use the example below to jump straight to any position.

SShape
EClearance
KTolerance
NHole /
chipbreaker
4Size (IC)
2Thickness
—Radius
AWiper lead
angle
FWiper clearance
angle
TEdge
preparation
NCutting
direction

Jump to: Shape · Clearance angle · Tolerance · Hole / chipbreaker · Size · Thickness · Corner radius · Wiper lead angle · Wiper clearance angle · Edge preparation · Cutting direction

Looking for turning inserts? See the Turning Insert Designation Chart, or use the interactive Code Builder to decode a full code at once.

Shape

First position. Defines the geometry of the insert and its nose angle.

Code 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°

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Clearance / Relief Angle

Second position. The angle between the flank of the insert and the workpiece.

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

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Tolerance

Third position. Manufacturing tolerance on corner points, thickness, and inscribed circles.

Code Corner point (in) Thickness (in) Inscribed circle (in) Corner point (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

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Hole / Chipbreaker

Fourth position. Describes the mounting hole and whether the insert carries a chipbreaker.

Code 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 double 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

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Size (Inscribed Circle)

Fifth position. The diameter of the largest circle that fits inside the insert.

ANSI code Inscribed circle size ISO code (metric cutting edge length) by shape code letter
Decimal in. Fractional in. C D R S T V W
0.5 .0625" 1/16"
1.2 (5) .15625" 5/32" S4 4mm 3mm 3mm 6mm
1.5 (6) .1875" 3/16" 4mm 5mm 4mm 4mm 8mm 8mm S3
1.8 (7) .21875" 7/32" 5mm 6mm 5mm 5mm 9mm 9mm 3mm
2 .25" 1/4" 6mm 7mm 6mm 6mm 11mm 11mm 4mm
2.5 .3125" 5/16" 8mm 9mm 7mm 7mm 13mm 13mm 5mm
3 .375" 3/8" 9mm 11mm 9mm 9mm 16mm 16mm 6mm
3.5 .4375" 7/16" 11mm 13mm 11mm 11mm 19mm 19mm 7mm
4 .5" 1/2" 12mm 15mm 12mm 12mm 22mm 22mm 8mm
4.5 .5625" 9/16" 14mm 17mm 14mm 14mm 24mm 24mm 9mm
5 .625" 5/8" 16mm 19mm 15mm 15mm 27mm 27mm 10mm
5.5 .6875" 11/16" 17mm 21mm 17mm 17mm 30mm 30mm 11mm
6 .75" 3/4" 19mm 23mm 19mm 19mm 33mm 33mm 13mm
6.5 .8125" 13/16"
7 .875" 7/8" 22mm 27mm 22mm 22mm 38mm 38mm 15mm
8 1" 1" 25mm 31mm 25mm 25mm 44mm 44mm 17mm
10 1.25" 1-1/4" 32mm 38mm 31mm 31mm 54mm 54mm 21mm
— 1.26" — 32mm

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Thickness

Sixth position. Overall thickness of the insert.

ANSI code ISO code Decimal Fractional Millimeter
.5 (1) — 0.03125" 1/32" 0.79mm
.6 T0 0.040" 1/25" 1.00mm
1 (2) 01 0.0625" 1/16" 1.59mm
1.2 T1 0.078" 5/64" 1.98mm
1.5 (3) 02 0.094" 3/32" 2.38mm
— T2 0.109" 7/64" 2.78mm
2 03 0.125" 1/8" 3.18mm
2.5 T3 0.156" 5/32" 3.97mm
3 04 0.187" 3/16" 4.76mm
— 05 0.219" 7/32" 5.56mm
4 06 0.25" 1/4" 6.35mm
5 07 0.313" 5/16" 7.9mm
6 09 0.375" 3/8" 9.53mm
8 — 0.5" 1/2" 12.7mm

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Corner Radius

Seventh position. The radius ground on the cutting corner.

ANSI code ISO code Decimal Fractional Millimeter
Null Null Wiper flat Wiper flat Wiper flat
V M0 0 0 0
0.2 00 0.004" — 0.1mm
X — 0.004" — 0.1mm
0 00 0.004" — 0.2mm
0.5 — 0.008" — 0.2mm
Y — 0.008" — 0.2mm
1 04 0.016" 1/64" 0.4mm
— 05 0.020" — 0.5mm
2 08 0.031" 1/32" 0.8mm
— 10 0.040" — 1.02mm
3 12 0.047" 3/64" 1.2mm
4 16 0.062" 1/16" 1.6mm
5 20 0.078" 5/64" 2mm
6 24 0.094" 3/32" 2.4mm
7 29 0.109" 7/64" 2.9mm
8 32 0.125" 1/8" 3.2mm

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Wiper Lead Angle

Eighth position. Milling inserts only.

Code Angle
A 45°
D 60°
K 60°
E 75°
L 75°
P 0°
S 75°

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Wiper Clearance Angle

Ninth position. Milling inserts only.

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

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Cutting Edge Preparation

Tenth position. Milling inserts only.

Code Edge preparation
F Sharp
E Honed
T T-land
S Honed T-land
X Special chamfer

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Cutting Direction

Eleventh position. Milling inserts only.

Code Direction
R Right-hand
L Left-hand
N Neutral

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Ready to cut

Once the geometry is settled, the grade and the holder decide how long it lasts. Browse the turning line built for tight tolerances under aggressive feeds.

FM Carbide Turning Inserts → Tool Holders Boring Bars

Not sure which grade matches your material? Use the Grade Look-Up.