Observed factory prices for turning, milling and drill inserts by ISO shape code — and why the piece price is the wrong number to compare.
Buyers compare the piece price. That is the wrong number. An insert is not one cutting edge — it is two, four, six or eight, and the shape you choose decides how many. What you actually pay per edge can differ by 50% between two inserts sitting at the same price on the same page.
| ISO letter | Shape | Point angle | Corners per side | Usable edges (negative) | Usable edges (positive) | Where it is used |
|---|---|---|---|---|---|---|
| S | Square | 90° | 4 | 8 | 4 | Strongest edge, most edges per insert. Heavy roughing. |
| W | Trigon | 80° | 3 | 6 | — | Six edges with an 80° included angle — the best edge count without sacrificing strength. |
| T | Triangle | 60° | 3 | 6 | 3 | Cheapest cost per edge. The volume turning workhorse. |
| C | Rhombic | 80° | 2 | 4 | 2 | Profiling and copy turning. Sharper point than T or W. |
| D | Rhombic | 55° | 2 | 4 | 2 | Profiling, shoulder work, internal boring. |
| V | Rhombic | 35° | 2 | 4 | 2 | Sharpest point, weakest edge. Profiling and finishing only. |
| M | Grooving | — | 1–2 | — | — | Grooving and parting. Priced per groove width, not per corner. |
| R | Round | — | continuous | — | — | Continuous edge, highest carbide volume, used for radius and profile work. |
Now run the arithmetic on a real quote. A CNMG 120408 and a WNMG 080412 are both listed around $1.30:
That is a 33% cost difference on the same job, and it is invisible if you only look at the piece price. The trigon gets six edges without giving up much edge strength, which is why it has quietly replaced the triangle in a lot of steel turning. It also has a genuine limitation: the trigon's 80° included angle cannot reach into the shoulder profiles a 55° or 35° rhombic can, so you buy it where the geometry allows, not everywhere.
Use this when you compare quotes. Ask each supplier to state usable edges per insert for the geometry they are quoting. Then divide. Two quotes that look 20% apart are frequently the same price per edge — and occasionally one is 40% cheaper than it looks.
| Insert | Geometry | Observed price / piece | MOQ |
|---|---|---|---|
| CNMG 120408 / 120412 | 80° rhombic, negative | $0.65 – 2.20 | 10 pcs |
| WNMG 080404 / 080412 | 80° trigon, negative | $0.65 – 2.00 | 10 pcs |
| WNMG 060404 | 80° trigon, negative (small) | $2.00 | 10 pcs |
| TNMG 160404 / 160408 | 60° triangle, negative | $0.65 – 1.70 | 10 pcs |
| DNMG 150608 | 55° rhombic, negative | $0.65 – 3.70 | 10 pcs |
| VNMG 160404 | 35° rhombic, negative | $0.65 – 2.50 | 10 pcs |
| VBMT 160404 / 160408 | 35° rhombic, positive | $0.65 – 2.20 | 10 pcs |
| CCMT 09T308 / 120408 | 80° rhombic, positive | $1.40 – 1.65 | 10 pcs |
| SNMG / SNMX 1206 | 90° square, negative | $0.65 – 2.20 | 10 pcs |
| MGMN 200 / 300 / 400 / 500 | grooving, external & internal | $0.85 – 1.50 | 10 pcs |
| ZCC·CT TNMG / CNMG | same geometry, Chinese market leader | $2.50 – 4.88 | 10 pcs |
The wide bands are real. The same CNMG 120408 is publicly listed from $0.65 to $2.20, and the difference is substrate grade and coating, not geometry. If your quote sits at the bottom of a band, ask what grade and what coating is in it before you place the order.
| Insert | Type | Observed price / piece | MOQ |
|---|---|---|---|
| APMT 1604 / APKT 1604 | 90° shoulder, P20, PVD | $0.80 – 1.80 | 10 pcs |
| SPMT 060205 / 1204 | square, universal | $0.28 – 0.35 | 100 pcs |
| WNMU 060408 / 080608 | trigon, universal | $0.65 – 1.52 | 10 pcs |
| RDMT 1204 / 1605 | round, radius milling | $0.65 – 1.52 | 10 pcs |
| SNMX 1206 | square, milling | $2.20 | 10 pcs |
| XDHT 0206-R0.1 | aluminium, high-rake | $0.28 – 0.35 | 100 pcs |
| SPMT / WCMX drill insert | U-drill and indexable drill body | $1.50 – 4.00 | 10 pcs |
| TPMX 0902 / 1403 / 1704 | deep-hole, gun-drill heads | $0.65 – 1.52 | 10 pcs |
| R424.9-13T308-23 | deep-hole drilling insert, CVD/PVD | $1.90 | 10 pcs |
| PCBN (hardened steel above 45 HRC) | high-CBN content, coated | $3.00 – 15.00 | 10 pcs |
| Cermet | finishing steel with high surface finish | from $2.00 | 10 pcs |
The first letter of the ISO code tells you the workpiece group, and it tells you the cost almost as well. The order below is consistent across every Chinese plant we quote: P is the commodity, S and H are the specialists.
| ISO class | Workpiece | Relative price | Why |
|---|---|---|---|
| P | Carbon and alloy steel | commodity — the cheapest class | Highest volume, most plants, most competition. This is where price shopping works. |
| M | Stainless and cast steel | commodity, slightly above P | Needs tougher substrate and a coating that resists built-up edge. |
| K | Cast iron, non-ferrous, non-metals | moderate | Simple WC–Co substrate, no expensive cubic carbides. Coating is often just TiN or CVD Al2O3. |
| N | Aluminium, copper, non-ferrous | moderate | High rake, polished surfaces, sometimes PCD or diamond coating. |
| S | Superalloys and titanium | the most expensive class | Heat-resistant substrate plus PVD AlTiN/AlCrN, often with a post-coat treatment. Low volume, high scrap. |
| H | Hardened steel and chilled cast iron | the most expensive class | Ultrafine substrate, very hard coating, negative geometry, additional edge prep. |
Practical consequence: if you are machining steel and stainless, you are in the most competitive part of the market and should be price-shopping hard. If you are machining titanium or hardened steel, you are paying for substrate and coating chemistry, and the cheapest quote is far more likely to be the wrong one. See the full ISO 513 grade reference →
Insert MOQ is almost always 10 pieces. That is deliberate — it is small enough to be a real test and large enough for the plant to recover its coating-furnace set-up. Our standard route:
We do not ask for a case study, a testimonial, or a commitment in exchange for the trial. Tool life is decided on your machine, on your material, with your operators. Nobody can predict it from a catalogue.
We will quote two grades against your current tool life, and measure substrate composition and coating thickness on the delivered batch so you are not comparing claims to claims.