Null                                        (close window)

In certain cases, a particular code letter or number in an insert designation is not relevant to defining the type, shape and size of the insert. In those instances, the code letter or number is often omitted, and the next code letter or number fills the next position in the designation.

Example 1: In the case of an insert that does not have a hole or a chipformer, no code letter is needed to define the Hole/Chipformer type in the fourth position of the designation. A value of 'N' can also be used to define no hole or chipformer, so it may be used to fill the fourth position at the manufacturer's discretion. Here are two designations that define the exact same insert:

TPG432 ('null' is used in the Hole/Chipformer fourth position to define no hole and no chipformer)
TPGN432 ('N' is used in the Hole/Chipformer fourth position to define no hole and no chipformer)

(Note: ANSI designations usually use the 'null' value; ISO designations usually use the 'N' value)

Example 2: In the case of a milling insert that has a wiper flat on each cutting edge instead of a cutting edge corner radius, no code number is needed to define the Radius value in the seventh position of the designation. In such an instance, no Radius value is stated in the insert designation, and the code number for the Wiper Lead Angle will immediately follow the Thickness code number in the designation. For example:

SEKN42AFTN (S=square, E=clearance angle, K=tolerance, N=hole/chipformer, 4=size, 2=thickness, no radius code number is stated, A=wiper lead angle, etc.)