Influencing factors and selection of the correct indexable insert

When selecting the most suitable peeling insert, the following criteria should be taken into account:

  • Composition and properties of the material to be machined
  • Hardness of the material
  • Diameter
  • Cutting depth
  • Required surface quality

The most important criterion for selecting the right peeling insert and its carbide quality is the material to be machined and its degree of refinement and hardness. However, sometimes major differences in material compositions mean that it is necessary to deviate from the listed recommendations - a practical test is a useful and supportive option here. Various cutting edge geometries and carbide qualities have been developed for different applications, which can be combined with different support chamfers.

A detailed description of the support chamfers and their selection criteria can be found on the following pages. An additional criterion is the diameter to be machined in conjunction with the cutting depth. The manufacturing process for the bars plays a significant role here: drawn and rolled bars with a diameter range of up to 150 mm usually have a better surface quality on the blank, in contrast to forged bars with diameters above 150 mm. In addition to an irregular surface structure, these may also exhibit cracks, cavities and material chipping.

→ Increased material removal and larger cutting depths are the consequence.

Other key influencing factors

In addition to the five selection criteria listed above, other influencing factors are also key when choosing the correct cutting insert:

  • Condition and properties of the peeling machine (maintenance)
  • Condition and accuracy of the tool holders and cartridges (seat insert and insert clamping)
  • Condition and setting of the guide elements (central supply, application of pressure, wear of rollers and sliding elements), etc.
  • Condition and properties of the raw bar (roundness, deflection, bar end hardening, chamfers, surface damage such as cracks, flat areas and chipping).
  • Sufficient cooling in the correct concentration, at sufficient pressure and volume directly on the cutting edge.
  • Optimum chip clearance - no chip jams in the peeling head

Important angles on the peeling indexable insert

  1. Secondary cutting edge
  2. Main cutting edge
  3. Setting angle
  4. Negative chamfer angle
  5. Cutting edge rounding
  6. Support chamfer angle
  7. Rake angle
  8. Angle of inclination

Support chamfer angle

Support chamfer type "S42"

(Support chamfer angle 4°)

Clearance angle on the support chamfer plus

Smooth cutting condition
"Positive insert"

Support chamfer type "S50"

(Support chamfer angle 5°)

Clearance angle on the support chamfer +/– 0°

Neutral condition 
"Insert engages positively with the bar"

* 5° support chamfer angle & 5° angle of inclination

Support chamfer type "S60"

(Support chamfer angle 6°)

Clearance angle on the support chamfer minus

Stable condition
"Negative insert"

Angle of inclination of the indexable insert in the cartridge is usually 5°

  1. Cartridge
  2. Indexable insert
  3. Shim
  4. Tool slide
  5. 5° angle of inclination

Different support chamfer finishes

Support chamfer type "S" (chamfer only on the secondary cutting edge)

  1. Insert thickness s
  2. Length of the secondary cutting edge Ln
  3. Setting angle k
  4. Depth of cut ap
  5. Main cutting edge
  6. Secondary cutting edge

Support chamfer type "P" (chamfer on the main and secondary cutting edge)

  1. Insert thickness s
  2. Length of the secondary cutting edge Ln
  3. Setting angle k
  4. Depth of cut ap
  5. Main cutting edge
  6. Secondary cutting edge

Overview of support chamfers

Chamfer Description Application area Tensile strength (Brinell hardness)
P60 Main and secondary cutting edge
Chamfer angle 6°
< Annealed >
E.g. structural steel, tool steel, main application for vibration-prone materials and unstable machine conditions
300–700 N/mm2
(90–210 HB)
S60 Secondary cutting edge
Chamfer angle 6°
< Annealed >
E.g. structural steel, tool steel
500–850 N/mm2
(150–250 HB)
P50 Main and secondary cutting edge
Chamfer angle 5°
< Hard rolled >
E.g. structural steel, tool steel, stainless steel (austenites)
450–800 N/mm2
(135–240 HB)
S50 Secondary cutting edge
Chamfer angle 5°
< Hard rolled >
E.g. structural steel, tool steel, stainless steel (austenites)
550–950 N/mm2
(160–280 HB)
P40 Main and secondary cutting edge
Chamfer angle 4°
< Hard rolled >
High temperature alloys
700–1100 N/mm2
(210–235 HB)
S42 Secondary cutting edge
Chamfer angle 4°
< Tempered >
E.g. tempering steel, tool steel, stainless steel (Duplex), Ni-based alloys
750–1200 N/mm2
(220–350 HB)
P30 Main and secondary cutting edge
Chamfer angle 3°
< Tempered >
E.g. tempering steel, tool steel, stainless steel (Duplex), Ni-based alloys
850–1350 N/mm2
(250–400 HB)
S30 Secondary cutting edge
Chamfer angle 3°
< Tempered >
E.g. tempering steel, tool steel
900–1500 N/mm2
(280–470 HB)

Recommended application area of the support chamfers based on the tensile strength of the steel material (N/mm2)

Recommended application area of the support chamfers based on the BRINELL hardness of the steel material (HB)