HSS Center Drills DIN 333 Type A & Type B – M35 Cobalt & M2, Full Ground, Bright & TiN Coated

Specification:
Material: HSS M2 / HSS-E M35 (5% Cobalt)
Standard: DIN 333
Type: Type A (60° chamfer only)
Type B (60° chamfer + 120° protection chamfer)
Manufacturing: 100% Full Ground
Surface Finish: Bright (Uncoated) / TiN Coated (Gold)
Shank Type: Straight Shank
Body Tolerance: H7
Size Range: 1-10mm
Application: Centre hole drilling on lathes and machining centers; suitable for steel, cast iron, aluminum, and non-ferrous metals

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Introduction

★ What is a DIN 333 Center Drill?
A center drill (also known as a combined drill and countersink) is a precision tool used to create a 60° conical center hole at the end of a workpiece before turning between centers on a lathe. The center hole provides a stable, accurate seating point for the tailstock center, ensuring concentricity throughout subsequent machining operations. DIN 333 is the internationally recognized German standard governing the geometry, dimensions, and tolerances of 60° center drills.

★ Type A vs. Type B — Which one do you need?
DIN 333 Type A features a single 60° chamfer. It is the standard choice for general-purpose centering where the workpiece will be machined immediately after centering. The open geometry makes it fast to use and easy to inspect.
DIN 333 Type B adds a 120° protective countersink at the entry of the hole. This protects the 60° seating surface from burrs, chips, and accidental damage during handling or between machining stages. Type B is preferred when workpieces need to be re-chucked multiple times, stored between operations, or held to tighter positional accuracy.

★ Material Options
M2 HSS (High Speed Steel) is the standard grade for center drills used in general machining environments. It offers good toughness, easy re-sharpening, and reliable performance on mild steel, aluminum, and non-ferrous metals.
M35 HSS-Co (Cobalt High Speed Steel, 5% Co) delivers significantly higher hot hardness and wear resistance compared to standard M2. It is the preferred choice for stainless steel, alloy steel, cast iron, and other difficult-to-machine materials, or in high-cycle production environments where tool life is critical.

★ Manufacturing Process — Full Ground
All center drills in this range are 100% full ground from solid bar stock. The grinding process is applied across the entire tool — body, pilot, and cutting geometry — rather than only the cutting end. Full ground production ensures superior dimensional accuracy, tighter runout tolerance, and a consistent surface finish on the 60° cone. This translates directly into better centering repeatability and longer tool life compared to milled or partially ground alternatives.

★ Surface Finish Options
Bright (uncoated) finish is the standard offering. The bare HSS surface provides a low-friction, easy-to-inspect condition suitable for most general machining applications.
TiN (Titanium Nitride) coating adds a hard, gold-colored ceramic layer to the cutting surfaces. TiN increases surface hardness to approximately HV 2300, reduces friction between the tool and workpiece, and extends tool life in moderate-to-high volume production. TiN-coated center drills are particularly effective when machining abrasive or gummy materials.

★ Typical Applications
• Lathe centering prior to turning between centers
• Spotting and start-hole preparation on machining centers
• Countersinking for mounting screws and fasteners
• Shaft end preparation in automotive, aerospace, and general engineering

★ Custom Sizes and OEM Supply
All items are available for OEM supply with custom packaging, size ranges, and coating options. Contact us for bulk pricing and lead times.