DIFFERENCES BETWEEN HSS, HSS-R, HSS-G, HSS-CO, TIN AND DIN 338 DRILLS: COMPLETE GUIDE
Differences between HSS, HSS-R, HSS-G, HSS-Co, titanium, and DIN 338 drill bits: a complete guide
HSS drill bits are essential for drilling metals, plastics, and engineering materials. But not all HSS drill bits are created equal: there are rolled, ground, cobalt, titanium-coated variants, and they all comply with specific DIN standards. This guide helps you choose the right drill bit for every application, avoiding errors and improving precision, durability, and safety.
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What does HSS mean?
HSS stands for High Speed Steel . It is designed to withstand the high temperatures generated during drilling, maintaining its cutting edge even under stress.
HSS drill bits are suitable for:
- mild steel
- iron
- aluminum
- copper and brass
- hard plastics
HSS-R drills: rolled
HSS-R drill bits are produced by cold rolling. They are economical, flexible, and suitable for standard drilling.
Characteristics
- good elasticity
- less precise tolerances
- average thermal resistance
- ideal for non-precision holes
Recommended materials
- mild steel
- iron
- aluminum
- plastic
HSS-G tips: ground
HSS-G tips are ground, making them more precise and aggressive in cutting.
Characteristics
- high precision
- less friction
- faster progress
- longer life than HSS-R
Recommended materials
- steel
- aluminum
- brass
- technical materials
HSS-Co drill bits: cobalt
HSS-Co drills contain a percentage of cobalt (5% or 8%), which increases hardness and heat resistance.
Characteristics
- very high heat resistance
- longer lifespan
- ideal for hard and abrasive materials
Recommended materials
- stainless steel
- alloy steels
- cast iron
- bronze
Titanium (TiN) HSS drill bits
Titanium nitride (TiN) coated bits are recognizable by their gold color. The coating reduces friction and increases durability.
Characteristics
- smoother scrolling
- less overheating
- longer life than standard HSS
Recommended materials
- steel
- aluminum
- hard plastics
What does DIN 338 mean?
DIN 338 defines:
- total length
- helix length
- tip angle (118°)
- dimensional tolerances
A DIN 338 compliant tip ensures consistent standards and professional compatibility.
Advanced comparison table
| Tip type | Production process | Precision | Heat resistance | Duration | Ideal materials | Recommended use |
|---|---|---|---|---|---|---|
| HSS-R | Rolling | Low | Average | Average | Mild steel, iron, plastic | Maintenance, standard holes |
| HSS-G | Correction | High | Good | High | Steel, aluminum, brass | Precise holes, professional use |
| HSS-Co | Steel + Cobalt | High | Very high | Very high | Stainless steel, cast iron, alloy steels | Hard materials, intensive use |
| HSS TiN | Titanium coating | High | High | High | Steel, aluminum, plastics | Repeated drilling, production |
| DIN 338 | Regulatory standard | Constant | Variable | Variable | All compatible materials | Professional applications |
Expert advice
Expert advice from Dinamitek
- For stainless steel, use only HSS-Co : other bits burn out in seconds.
- Always lubricate when drilling hard metals: it reduces heat and prolongs the life of the bit.
- Do not use high speeds on hard materials: you risk overheating the bit.
- Always clamp the piece : avoids vibrations and improves precision.
- If you have to make many repeated holes , choose TiN or HSS-G drill bits.
- For deep holes , use DIN 338 or DIN 340 (long) drill bits.
Common Mistake → Solution
Common mistakes and how to avoid them
Error: Using HSS-R bits to drill stainless steel.
Solution: Use only HSS-Co bits (5% or 8% cobalt).
Error: Drilling hard metals at high speed.
Solution: Set a low speed and use cutting lubricant.
Error: Do not clamp the workpiece to be drilled.
Solution: Use clamps or a vise to avoid vibrations.
Error: Continue using worn tips.
Solution: Replace the tip or sharpen it with appropriate equipment.
Mistake: Using TiN tips thinking they are good for stainless steel.
Solution: TiN improves sliding and durability, but is not a replacement for HSS-Co.
You may also be interested in
HM or HSS cutter? A selection guide for professional metal drilling.
Technical Glossary
- HSS – High-speed steel, heat-resistant.
- HSS-R – Rolled drill bits, economical and versatile.
- HSS-G – Ground, precise and professional tips.
- HSS-Co – Cobalt drill bits, ideal for stainless steel and hard materials.
- TiN – Titanium nitride coating, gold color.
- DIN 338 – Technical standard defining dimensions and angles.
- Tip Angle – Affects aggression and accuracy.
- Helix – The spiral that evacuates the chip.
- Cutting Lubricant – Reduces friction and heat.
- Alloy steel – Steel with additional elements that increase its hardness.
HSS drill bits aren't all the same: rolled, ground, cobalt-coated, titanium-coated, or DIN 338-compliant, each is designed for a specific purpose. Choosing the right drill bit means working better, faster, and with greater precision.
Do you want to buy professional HSS drill bits?
Visit the Dinamitek selection
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