19
2025
-
12
How to Choose the Right HSS Drill Bit
How to Choose the Right HSS Drill Bit
Selecting the correct HSS drill bit depends on three key factors: the material you’re drilling, your drilling tool, and the desired hole precision. Follow this step-by-step guide:
Step 1: Match the Bit to the Drilling Material
Wood/Plastic: Standard HSS-G bits (uncoated or black oxide) work best. They drill cleanly without damaging soft materials.
Aluminum/Brass/Copper: HSS-G bits with spiral flutes for efficient chip evacuation. Use cutting oil to prevent material buildup on the bit.
Mild Steel/Alloy Steel: HSS-G bits (135° point angle) for general use; upgrade to HSS-Co for thicker or harder steel.
Stainless Steel/High-Strength Metal: HSS-Co bits with TiN coating are mandatory. The cobalt enhances hardness, and the coating reduces friction.
Step 2: Choose the Right Shank Type
The shank (the part that fits into the drill chuck) must match your tool:
Straight Shank: Compatible with most handheld electric drills and impact drivers. Ideal for DIY users and small workshops due to its low cost and easy replacement.
Taper Shank: Designed for drill presses and milling machines. It provides better rigidity and stability for high-precision, high-volume drilling (e.g., factory production lines).
Step 3: Consider Drill Bit Geometry
Key geometric features affect drilling performance:
Point Angle: 135° is best for metal (self-centering, fast drilling); 118° is common for wood/plastic (sharp cutting edge).
Spiral Angle: Higher spiral angles (30-40°) are good for soft materials (fast chip removal); lower angles (15-25°) work better for hard metals (stable cutting).
Flute Design: Spiral flutes are standard for most materials; straight flutes are used for brittle materials like cast iron.
