Carbide Drill Bits

Solid Carbide Drill Bits — Hardened Steel, Stainless & Composite Drilling

Solid carbide drill bits are the correct tool for drilling hardened steel, abrasive materials, stainless steel, cast iron and composites where high-speed steel (HSS) drills would rapidly dull or fail. The tungsten carbide substrate is significantly harder and more heat-resistant than HSS, allowing higher cutting speeds and longer tool life in difficult materials. AIMS Industrial supplies solid carbide drills for engineering workshops, toolrooms and machining operations across Australia.

Browse drill bit options at AIMS:

• Solid carbide drill bits — this page — for hardened, abrasive and stainless materials
• Cobalt drill bits (M35, M42) — bridge between HSS and carbide for stainless and tough alloys
• Standard HSS jobber drills — the general workshop drill for mild steel, aluminium, plastics
• Centre drills — spotting and starter holes
• Browse the full drilling range

When to use carbide vs HSS

HSS drills are the right choice for the majority of drilling tasks — mild steel, aluminium, copper, brass and most engineering plastics. Carbide becomes the correct specification when:

• Drilling hardened steel or tool steel above 40 HRC
• Drilling abrasive materials including graphite, fibreglass and carbon fibre composites
• Drilling cast iron, which contains hard abrasive phases that rapidly dull HSS
• High-production drilling where tool-change frequency must be minimised
• Drilling stainless steel in production quantities where HSS tool life is insufficient

For tougher-than-HSS but not-yet-carbide work — particularly stainless and work-hardening alloys in lower volume — cobalt drill bits bridge the cost/performance gap. Cobalt drills handle stainless and tough alloys at HSS prices.

Carbide drills should not be used in hand drills or non-rigid setups — they are brittle and will snap if subjected to the flex and run-out of a hand-held drill. They require a rigid machine (drill press, CNC machining centre or lathe) for safe and effective use.

Coatings & grades

AIMS stocks solid carbide drills in uncoated, TiN (titanium nitride) and TiAlN (titanium aluminium nitride) coatings. Uncoated carbide is the default for non-ferrous and lower-temperature applications. TiN extends life by 2-3× in steel applications. TiAlN handles the highest cutting temperatures and is the standard coating for high-speed dry drilling of hardened steel and stainless. The carbide grade itself (micrograin sizes typically 0.5-1.0 micron) affects toughness vs wear resistance — finer grains for harder materials, coarser for tougher work.

Drill bit sizing & tap drill calculations

For complete drill bit size reference (metric and imperial cross-reference, fractional vs decimal equivalents, drill point geometry), see our drill bit size chart — one of the most-used reference articles on the site. For tap drill sizing (the drill diameter required before threading), see the threading tap size chart.

Companion ranges at AIMS

Solid carbide drills sit within our broader drilling range. For drill chucks, adaptors and accessories, see drill chucks and drill accessories and adaptors. For step drilling, see step drill bits. Reduced-shank carbide drills for larger diameters in standard chucks are catalogued under reduced shank drill bits.

For help selecting the right carbide drill grade, coating and geometry for your material and machine, call (02) 9773 0122 or contact our team.