Reference Guide
A turning insert is identified by a seven-position ANSI code. Each position describes one physical feature of the insert. Use the example below to jump straight to any position, or scroll through the full reference tables.
Jump to: Shape · Clearance angle · Tolerance · Hole / chipbreaker · Size · Thickness · Corner radius
Looking for milling inserts? See the Milling Insert Designation Chart, or use the interactive Code Builder to decode a full code at once.
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° |
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° |  |
Third position. Manufacturing tolerance on corner point, thickness and inscribed circle.
| 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 |
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 |
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 | ||||||
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 |
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 |