Understanding HSS and Carbide
The choice between High Speed Steel (HSS) and Carbide is one of the most important decisions when selecting a rotary file, bur, or countersink. Both materials have distinct advantages, and the right choice depends on your workpiece material, production volume, and budget.
Severance offers most product lines in both HSS and Carbide, so you can choose the optimal tool material for each specific application. Here is what you need to know to make the right call.
Quick Answer
Choose HSS for general-purpose work, lower budgets, and materials under Rc 45.
Choose Carbide for hardened materials, high production, and when tool life is critical.
Material Properties Comparison
| Property | HSS (M2 High Speed Steel) | Carbide (Tungsten Carbide) | Winner |
|---|---|---|---|
| Hardness | Rc 63–65 | Rc 89–93 (HRA) | Carbide — significantly harder |
| Toughness | High — resists chipping and breakage | Moderate — harder but more brittle | HSS — better shock resistance |
| Heat Resistance | Maintains hardness to ~1,100°F | Maintains hardness to ~1,400°F | Carbide — handles higher temperatures |
| Wear Resistance | Good | Excellent — 10–20× longer life | Carbide — dramatically longer life |
| Cutting Speed | 150–300 SFM | 300–600 SFM | Carbide — runs at 2× the speed |
| Initial Cost | Lower (baseline) | 3–5× higher than HSS | HSS — lower upfront cost |
| Cost Per Part | Higher in production | Lower in production (fewer tool changes) | Carbide — in high-volume applications |
| Regrindability | Easy — standard grinding wheels | Requires diamond grinding wheels | HSS — easier and cheaper to regrind |
| Max Workpiece Hardness | Up to Rc 45 | Up to Rc 65+ | Carbide — cuts hardened steel |
When to Choose HSS
Ideal Applications
- General-purpose deburring on mild steel, aluminum, brass, and plastics.
- Low-volume or one-off jobs where tool life is not the primary concern.
- Interrupted cuts such as deburring cross-holes, slots, or keyways where impact loading occurs.
- Tight budgets where initial cost matters more than cost-per-part.
- Hand-held operations where the operator may accidentally impact the tool against the workpiece.
Advantages
- Lower initial purchase price (typically 1/3 to 1/5 the cost of carbide).
- More forgiving of operator error and poor setup conditions.
- Less likely to chip or fracture on impact.
- Easy to resharpen—can be reground on standard grinding wheels.
- Available in the widest range of shapes and sizes.
Severance HSS Products
- HSS Midget Mills (EDP 23000–23237)
- HSS Junior Mills (EDP 22720–22747)
- Lab Mills (HSS only, EDP 22620–22673)
- Chatterless Countersinks
When to Choose Carbide
Ideal Applications
- Hardened materials (tool steel, stainless steel, heat-treated alloys above Rc 45).
- High-production environments where tool changes cost time and money.
- Abrasive materials (cast iron, fiberglass, composites, ceramics) that eat through HSS.
- High-speed applications where faster material removal is needed.
- Extended runs where consistent tool performance over many parts matters.
Advantages
- 10–20× longer tool life compared to HSS on most materials.
- Runs at 2× the surface speed for faster stock removal.
- Maintains sharp cutting edges much longer.
- Handles heat better—less likely to lose temper at high speeds.
- Lower cost per part in production despite higher initial cost.
Severance Carbide Products
- Carbide Midget Mills (EDP 23300–23537)
- Carbide Junior Mills (EDP 22820–22846)
- Carbo-Mills (EDP 22180–22592)
- Sever-Cuts (EDP 23680–23710)
- Carbide Hand Files
Cost Analysis: Initial Price vs. Total Cost Per Part
The sticker price of a tool is only part of the equation. In production environments, the total cost per part is what matters, and that includes tool cost, change time, downtime, and scrap rate.
| Cost Factor | HSS Tool | Carbide Tool |
|---|---|---|
| Initial tool cost (example) | $15 | $60 |
| Parts per tool life | 100 parts | 1,500 parts |
| Tool cost per part | $0.15/part | $0.04/part |
| Tool changes per 1,000 parts | 10 changes | 0.67 changes |
| Downtime cost (@ $2/min, 5 min/change) | $100 | $6.70 |
| Total cost per 1,000 parts | $250 | $46.70 |
Break-Even Point
Carbide typically becomes the more economical choice when you are processing more than 50–100 parts with the same tool. Below that volume, HSS usually wins on total cost.
For one-off or prototype work, HSS is almost always the smarter buy. For production, carbide pays for itself quickly.
Application-Specific Recommendations
| Application | Recommended Material | Why |
|---|---|---|
| General shop deburring (mild steel) | HSS | Cost-effective for everyday maintenance and repair work. |
| Weld blending (structural steel) | HSS or Carbide | HSS for occasional use; Carbide if blending welds all day. |
| Stainless steel deburring | Carbide | Stainless work-hardens and is abrasive. Carbide holds its edge. |
| Cast iron deburring / cleaning | Carbide | Cast iron is extremely abrasive. HSS dulls quickly. |
| Aluminum deburring (production) | Carbide (Sever-Cut) | Sever-Cut chip-breaker pattern prevents aluminum from loading the flutes. |
| Die and mold work (tool steel) | Carbide | Often working on hardened or semi-hardened tool steel. Carbide required. |
| Porting / flow work | HSS or Carbide | HSS for cast aluminum heads; Carbide for cast iron. |
| Fiberglass / composites | Carbide | Fiberglass is extremely abrasive. HSS may last only minutes. |
| Prototype / one-off parts | HSS | Lower initial cost when you only need a few cuts. |
| Dental / jewelry detail work | HSS (Lab Mills) | Lab Mills are only available in HSS. Fine detail at low loads. |
| Cross-hole deburring (interrupted cut) | HSS | HSS toughness handles the intermittent impact without chipping. |
| Production line deburring cell | Carbide | Minimize tool changes and maximize throughput. |
Regrind Considerations
Both HSS and Carbide tools can be reground to restore cutting performance, but there are important differences:
| Factor | HSS Regrind | Carbide Regrind |
|---|---|---|
| Grinding wheel required | Aluminum oxide (standard) | Diamond wheel (specialized) |
| Regrind cost | Lower | Higher (but still less than a new tool) |
| Number of regrinds | 2–4 typical | 2–3 typical |
| Performance after regrind | Near-original when done properly | Near-original when done properly |
Severance offers a professional regrind service for both HSS and Carbide tools. Sending worn tools for regrinding rather than discarding them can save 40–60% compared to buying new, while restoring the original factory geometry and cutting performance.
Regrind Service
Save 40–60% by regrinding your worn Severance tools instead of replacing them.
Learn MoreThe Bottom Line
Choose HSS When:
- Working on soft to medium-hard materials (under Rc 45)
- Doing low-volume or one-off work
- Budget is the primary constraint
- Interrupted cuts or impact loading is expected
- Easy regrindability is important
Choose Carbide When:
- Working on hardened materials (over Rc 45)
- Running production volumes (50+ parts)
- Cutting abrasive materials (cast iron, composites)
- Faster cycle times are needed
- Consistent tool performance over long runs matters