Step Drill 4-30mm HSS — Professional-Grade Multi-Stage Drilling

This is the workhorse step drill for any professional shop. The 4-30mm range covers the majority of standard hole sizes in automotive, pneumatic, and general assembly work. The dual relief angle geometry is the key differentiator here—it's not just a cosmetic feature, it's a design that meaningfully extends tool life and improves cutting performance.

If you're stocking single bits, consider adding a complete step drill set with multiple bit sizes or exploring TiN-coated spiral groove alternatives for shops that demand maximum durability in high-volume production.

Key Features

• Dual Relief Angle Design: First relief angle provides positive cutting action; second relief creates clearance space for efficient cooling. This prevents heat buildup that typically causes premature bit wear.
• Multi-Step Conical Head: 4mm to 30mm range in progressive increments. Engraved step markings on the bit flank for quick diameter reference.
• Material-Specific Relief Angles: Multiple relief geometry options allow optimization for soft materials (aluminum, plastics) through hard materials (cast iron, steel). This flexibility reduces breakage and heat generation across application range.
• Straight/Hex Shank Design: Quick compatibility with standard drill chucks and quick-change systems.
• Extended Tool Life: Dual relief system and optimized flute geometry deliver considerably longer service life compared to single-relief step drills of equivalent size.
• Smooth, Low-Heat Operation: Engineered cooling paths prevent thermal stress accumulation during extended drilling runs.

Why This Matters for Your Margins

Tool Longevity = Customer Loyalty. Shops that experience dramatic tool life improvements will return. This step drill's dual relief design is a genuine engineering advantage—not marketing language. When a customer's production rate stays consistent longer with fewer bit replacements, they remember the supplier who recommended it.

Range Coverage: A single 4-30mm bit eliminates the need to stock multiple smaller step drills for common applications. Lower inventory complexity, higher per-unit sales volume.

Reputation Build: Distributing a tool with visibly superior cooling performance positions your shop as knowledgeable and quality-focused.

Technical Specifications

Specification	Detail
Diameter Range	4mm to 30mm (progressive steps)
Material	High-Speed Steel (HSS)
Relief Design	Dual-angle: positive cutting relief + clearance cooling relief
Flute Type	Straight or spiral available (depends on material need)
Shank Type	Straight/hex, standard chuck-compatible
Cutting Edge	Sharp machined edges between each step
Surface Finish	Metallic, precision-ground
Heat Management	Optimized coolant pathways reduce operating temperature

Bottom Line

Stock this bit. It's a straightforward, high-performing tool that resellers can confidently recommend without reservation. The dual relief angle isn't theoretical—it's measurable performance that shops will notice immediately. For bulk orders, consider pairing with complementary step drill sets to round out customer options.