Buy Tool Steels Online in Australia
AIMS Industrial stocks two families of tool steel for Australian toolrooms, workshops and maintenance teams: high-speed steel (HSS) blanks — M2 general-purpose and M42 cobalt — in round and square bar for grinding custom cutting tools, and Erasteel silver steel round bar, a precision-ground high-carbon tool steel used for punches, pins, dies and gauges. Both are supplied in metric and imperial sizing so you're not forced to convert to fit an older machine or an imperial drawing. Not sure which one suits your job? Our Steel Grades Comparison Chart: Carbon, Alloy & Tool Steels covers selection in detail.
Tool steel selection matters because the wrong grade in the wrong job means a tool that dulls too fast, a punch that chips, or a ground component that won't hold its diameter after hardening. This page covers the two grade families AIMS stocks, how they differ, and where each earns its place in a toolroom — plus what to do if your job calls for a dedicated die or mould steel we don't carry as standard bar stock.
Tool Steel Quick Reference
| Grade | Type | Typical Hardness | Primary Application |
|---|---|---|---|
| M2 (HSS) | General-purpose high-speed steel | ~63–65 HRC (heat-treated) | Boring bars, fly cutters, form tools and general-purpose custom cutting tools ground in the toolroom |
| M42 (HSS-Co) | Cobalt high-speed steel (~8% Co) | ~66–68 HRC (heat-treated) | Cutting tools for stainless, work-hardening and harder alloys where standard M2 dulls quickly |
| Silver Steel | High-carbon water-hardening tool steel | Ground bar — hardened by the toolmaker as required | Punches, pins, dowels, gauges and small dies needing close diameter tolerance |
Hardness figures above are typical published values for these grade families after heat treatment, given as a reference point — not a certified spec for a specific batch. Confirm supply condition and exact tolerances with our team before finalising a design.
The tool steel grades we stock
M2 high-speed steel (HSS)
M2 is the standard general-purpose high-speed steel grade used across Australian toolrooms. It holds a cutting edge at the elevated temperatures generated at the tool tip during machining — the "red hardness" that separates HSS from plain high-carbon tool steel — and is ground and reground many times over its working life. AIMS stocks M2 as round and square bar blanks, the starting material for grinding boring bars, fly cutter bits, form tools, thread chasers and other special-purpose lathe and mill tooling not available off the shelf. M2 suits general turning and milling of mild steel, aluminium and other non-ferrous metals.
M42 cobalt high-speed steel (HSS-Co)
M42 is a cobalt-enriched high-speed steel — cobalt is typically added at around 8% — which increases hot hardness and wear resistance beyond standard M2. Where M2 dulls quickly against stainless steel, work-hardening alloys or other harder materials, M42 holds its edge longer. AIMS stocks M42 as round and square blanks (marketed as "HSS Co" or "Cobalt" tool steel), so a toolmaker grinding a custom cutting tool for a harder material can select the cobalt grade without switching to carbide.
Erasteel silver steel round bar
Silver steel is a high-carbon, water-hardening tool steel supplied as precision-ground round bar with a bright ("silver") finish and tight diameter tolerance — the standard toolroom material wherever an accurate, hardenable round section is needed without a separate turning operation. AIMS stocks Erasteel silver steel, a specialty steel manufacturer, in both metric and imperial diameters. It's the go-to stock for punches, pins, dowels, gauges and small dies, and for any component where close diameter tolerance eliminates the need to turn to size before hardening. As a water-hardening grade it can be hardened by water quench and tempered to the hardness the application requires — confirm the as-supplied condition (soft or pre-hardened) with our team when ordering, since this can vary by size and batch.
How to choose: HSS or silver steel?
The decision comes down to what the finished part actually does. If it's a cutting edge — a boring bar, a form tool, a custom lathe or mill cutter — you need a grade with red hardness, which means HSS. Choose M2 as the default general-purpose grade; step up to M42 cobalt when the tool will be cutting stainless steel, work-hardening alloys, or other material that dulls a standard M2 edge quickly.
If the finished part is a punch, pin, dowel, gauge or small die rather than a cutting edge, silver steel is the better starting stock — its value is dimensional accuracy and hardenability, not red hardness. A ground silver steel bar close to finished diameter also saves a turning operation that a rougher HSS blank or general bar stock would require.
Round versus square section follows the tool geometry: round stock for boring bars and turned components, square stock for lathe toolpost tools, form tools and grooving/threading blanks ground on multiple faces. Metric or imperial sizing should match the toolholder or drawing you're working to — AIMS stocks both so the job dictates the choice, not the shelf.
Available sizes and formats
HSS and HSS-Co blanks are stocked in round and square section, in both metric (millimetre) and imperial (fractional inch) sizing, across a practical range of small-to-medium toolroom diameters and section sizes suited to boring bars, fly cutters and custom lathe tooling. Erasteel silver steel round bar is stocked in metric diameters and imperial (fractional inch) diameters, precision-ground to close tolerance and supplied in standard bar lengths. Exact sizes, lengths and current stock levels are listed on each product page — variant availability changes with stock, so check the product page or contact us for a size not currently listed.
Where these tool steels earn their place
- Toolroom manufacture of boring bars, fly cutter bits and special-purpose turning tools
- Grinding custom form tools, grooving tools and profile cutters for lathe work
- Thread chasers and other custom threading tools ground to a specific profile
- Punch, pin, dowel and gauge manufacture from silver steel round bar
- Small dies and toolroom fixtures requiring close diameter tolerance before hardening
- Cutting tools for harder alloys and stainless steel where M42 cobalt HSS outlasts standard M2
Looking for a different tool steel grade?
AIMS's stocked tool steel range is focused on HSS toolroom blanks (M2 and M42 cobalt) and Erasteel silver steel round bar — it does not currently include dedicated cold-work die steels (such as O1, A2 or D2), hot-work steels (such as H13), or pre-hardened mould steels (such as P20) as standard bar stock. If your job calls for one of these grades, contact our team or call (02) 9773 0122 — we can advise on sourcing options and point you to a suitable alternative from what we do stock.
Companion ranges at AIMS
Tool steel sits alongside AIMS's broader engineering material and toolmaking range. For related stock, see key steel for keyway stock, shims & shim stocks for precision shimming, bronze bar stock for bearing applications, and the full raw materials range for other engineering metal stock. For finished cutting tools rather than blanks, see Sutton Tools, carbide drill bits, cobalt drill bits, end mills & milling cutters and milling inserts. For measuring and gauging equipment to check your finished tools, see measuring tools.
For background on choosing between HSS and carbide for a cutting application, see our HSS vs carbide guide and cutting speeds & feeds chart for HSS, cobalt and carbide.
For tool steel grade selection, sizing or a grade not listed here, call (02) 9773 0122 or contact our team — we're happy to talk through the application before you order.
Tool Steel FAQs
What tool steel grades does AIMS Industrial stock?
AIMS stocks high-speed steel (HSS) tool steel blanks — M2 general-purpose and M42 cobalt — in round and square bar, metric and imperial sizes, plus Erasteel silver steel precision-ground round bar in metric and imperial diameters. These are the toolroom staples for grinding custom cutting tools and for punch, pin and gauge manufacture.
What's the difference between M2 and M42 HSS?
M2 is the standard general-purpose high-speed steel grade, suited to grinding cutting tools for mild steel, aluminium and general machining work. M42 is a cobalt-enriched HSS grade (typically around 8% cobalt) with higher hot hardness, better suited to grinding tools for harder alloys, stainless steel and work-hardening materials where M2 dulls quickly.
What is silver steel and what's it used for?
Silver steel is a high-carbon, water-hardening tool steel supplied as precision-ground round bar with a bright ground finish and tight diameter tolerance. It's the standard toolroom material for punches, pins, dowels, gauges and small dies where diameter accuracy matters and the finished part will be hardened after machining.
Do I need to heat-treat these tool steels myself?
HSS blanks are conventionally supplied already hardened, ready to grind directly into a finished tool — HSS requires high-temperature furnace treatment with controlled atmosphere well beyond general workshop capability, so it's ordered hardened as standard trade practice. Silver steel is a water-hardening grade; confirm the as-supplied condition (soft or pre-hardened) with our team when ordering, and use a qualified heat-treatment provider if you need to harden it after machining.
What sizes are these tool steels available in?
HSS and HSS-Co bar is stocked in round and square section, in both metric and imperial (fractional inch) sizing, across a range of toolroom diameters and section sizes. Silver steel round bar is stocked in metric and imperial diameters. Exact sizes and current stock are shown on each product page — for a size not listed, contact our team.
Can I get O1, D2, A2, H13 or other dedicated die and mould steels from AIMS?
Not as standard stocked bar in this range — our tool steel range is focused on HSS toolroom blanks and Erasteel silver steel round bar. If your job calls for a dedicated cold-work, hot-work or mould steel grade, contact our team — we can advise on sourcing options.
What's the difference between HSS and silver steel for toolroom work?
HSS is chosen for cutting tools that need to hold a sharp edge at elevated temperature — the red hardness that lets a tool keep cutting as friction heats the tip. Silver steel is a high-carbon steel chosen for dimensional accuracy and hardenability, better suited to punches, pins, gauges and dies than to cutting-edge tools.
How do I choose between metric and imperial stock?
Match the stock size to your machine's toolholder or the finished component's design standard — Australian workshops commonly work in both systems depending on the job and the age of the equipment. AIMS stocks both metric and imperial HSS and silver steel bar so you're not forced to convert.