W: Indicates a Trigon shape (an 80-degree three-sided polygon), giving the insert 3 strong, indexable cutting edges.
C: Denotes a 7-degree positive clearance angle, which reduces cutting friction and heat buildup.
M: Specifies standard manufacturing tolerances for the insert's height and thickness.
T: Represents a countersunk clamping hole with a single-sided chipbreaker geometry.
08: The nominal cutting edge length is roughly 8.7 mm.
04: The thickness of the insert is exactly 4.76 mm.
12: The corner radius (nose radius) is 1.2 mm. A thicker 1.2 mm radius provides immense edge strength to prevent chipping during rough drilling operations.
Grade Meaning (AP35)
AP35 is a PVD (Physical Vapor Deposition) coated carbide grade.
It is engineered as a general-purpose to heavy-interrupted cutting grade.
It performs exceptionally well at handling moderate-to-low cutting speeds with high feed rates. The tough substrate absorbs the severe impact shocks experienced when a U-drill first punches into hard metal components.
Primary Material Applications (ISO Class)
This specific grade and radius configuration is ideal for drilling:
P-Class (Steels): Carbon steels, alloy steels, and structural steel blocks.
M-Class (Stainless Steel): Highly effective against sticky materials like 304 or 316 stainless steel.
K-Class (Cast Iron): Can be used on ductile and grey iron profiles.