D8: The cutting diameter (flute diameter) is exactly 8 mm.
60: The total overall length (OAL) of the tool from tip to shank end is 60 mm.
4T: Indicates a 4-Flute configuration (4 teeth/cutting edges).
Note on Shank: For an 8 mm cutting diameter (D8), the shank diameter is almost always 8 mm as well (straight shank).
Key Applications of 4-Flute 8mm End Mills
Finishing Operations: A 4-flute configuration offers a slower chip clearance area but provides an incredibly smooth surface finish compared to 2-flute varieties.
Side Milling & Slotting: Ideal for profile milling, contouring, and shallow slotting.
Material Suitability: Depending on the coating, it is used to mill Steels (up to 45/55/65 HRC), Stainless Steel, Cast Iron, and exotic alloys.
Common Variants Based on Material Hardness (HRC)
When purchasing, you will need to choose the tool's hardness rating to match your job piece:
45 HRC (Uncoated / AlTiN): Best for soft steels, structural metals, and aluminium.
55 HRC (Tisin / AlTiN Coated): Standard industrial grade for die steel, alloy steel, and carbon steel.
65 HRC (NaCo / Blue Coated): Premium micro-grain carbide for hardened mold steels and heavy industrial milling.