SEMT 12T3 Milling Inserts
Compare suitable materials and applications, then choose a brand to view the exact SKUs.
- ISO Code
- SEMT12T3
- Insert Size
- 12T3
- Shape
- S — Square
- Radius
- 1.5 mm
- Thickness
- 3.97 mm
- d / IC
- 13.4 mm
- Relief Angle
- 20°
Find the Right Option
Select the workpiece material and application. Brand remains optional.
Brands
All available options for this parent model.
This page covers every SEMT 12T3 insert we can supply — 15 variants across Achteck, published for Steel, Stainless steel, Cast iron, Heat-resistant alloys. The square 90° geometry gives it 8 cutting edges and makes it suitable for heavy roughing, square shoulders and interrupted cuts.
Milling inserts are chosen to match the cutter body — lead angle, number of teeth and the geometry designated by the manufacturer. The milling insert selection guide walks through that; this page lists what we actually hold in SEMT 12T3.
Geometry and dimensions
| Insert family | SEMT |
|---|---|
| Category | Milling Inserts |
| Shape | square 90° (S) |
| Usable cutting edges | 8 |
| Inscribed circle (IC) | 13.4 mm |
| Thickness (S) | 3.97 mm |
| Nose radius (RE) | 1.5 mm |
| Cutting edge length (L) | 8.8–9 mm (typically 8.8 mm) |
| Fixing hole diameter (D1) | 4.1 mm |
| Hand | Neutral |
| Variants in stock | 15 |
| Brands | Achteck |
Cutting data
The 15 variants of SEMT 12T3 listed here are supplied without a full published cutting-data set, so we do not publish one. Ask us for the specific grade and chipbreaker you are considering and we will send the manufacturer's window for it.
Carbide grades available
15 variants of SEMT 12T3 are stocked in these grades: AC151K, AP251K, AP403M, AP251U, AP351M, AP403S, AC251P.
Across this range the grades specified most often are AC151K, AP251K, AP403M, AP251U, AP351M. Within one brand's range, a higher middle digit usually means a tougher grade — better on interrupted cuts, slightly less wear resistant. See carbide grades explained for how to read the names.
Chipbreaker geometries
Chipbreakers stocked for SEMT 12T3: MM3, MM4, MR6.
For milling, the geometry code marks the intended duty — sharper for light cuts and better finish, stronger for scale and interruption. Milling insert selection guide.
Typical applications
- Face milling
For more on cutting steel, see our material-specific guide.