High-performance turning insert for demanding stainless steel applications
The positive DCMT...-MM RT255M indexable insert is a well-thought-out solution for longitudinal and contour turning in medium machining applications. Equipped with the specialized RT255M grade, which relies on a PVD-coated M20-M30 carbide substrate, this tool provides excellent thermal stability and reliable wear resistance. This combination creates great conditions for consistent and predictable workflows, even under slightly interrupted cutting conditions. With its 55° basic shape and the -MM chipbreaker tailored for stainless steels, the insert ensures secure process control and meets the high standards of industrial manufacturing.
Suitable materials

Technical data
- Insert shape: DCMT
- Application range: Medium machining
- Cutting conditions: Continuous and light interrupted cut
- Material suitability: Stainless steel
- Coating: RT255M (PVD-coated M20-M30 solid carbide)
- Packaging unit: 10 pieces
Dimensions of DCMT...-MM RT255M
| |
Item Nr. |
r |
L |
I.C. |
S |
d |
| DCMT 070204-MM RT255M |
1777341 |
0,4 |
7,8 |
6,35 |
2,38 |
2,8 |
| DCMT 070208-MM RT255M |
1777342 |
0,8 |
7,8 |
6,35 |
2,38 |
2,8 |
| DCMT 11T304-MM RT255M |
1777343 |
0,4 |
11,6 |
9,525 |
3,97 |
4,4 |
| DCMT 11T308-MM RT255M |
1777344 |
0,8 |
11,6 |
9,525 |
3,97 |
4,4 |
Cutting data
|
Stainless Steel |
|
Vc (m/min) |
fz (mm) |
ap (mm) |
DCMT 070204-MM RT255M
|
100-200 |
0,06-0,17 |
0,2-1,5 |
| DCMT 070208-MM RT255M |
100-200 |
0,08-0,2 |
0,5-1,5 |
| DCMT 11T304-MM RT255M |
100-200 |
0,08-0,27 |
0,25-3 |
| DCMT 11T308-MM RT255M |
100-200 |
0,08-0,27 |
0,3-3 |
Applications
The DCMT...-MM insert is exceptionally suited for universal turning tasks in general mechanical engineering, as well as in specialized plant and stainless steel construction. It is explicitly designed for medium-duty machining processes in stainless steels, delivering constant results across both continuous and slightly interrupted turning operations. Thanks to the compact diamond shape, the tool holder can be flexibly positioned along complex workpiece contours.
Special features
The PVD coating of the M20-M30 micro-grain carbide effectively shields the cutting edge against rapid wear and thermal stress, which proves to be a decisive advantage when working with tough stainless steels. The -MM chipbreaker is deliberately optimized to break chips in a controlled manner at medium depths of cut, aiding in smooth chip evacuation. The availability of four different variants also makes it possible to match the tool exactly to the specific demands regarding surface finish and edge stability.