Tooth geometry determines how much hair a thinning shear removes, but the edge grind dictates how it feels and which techniques remain safe. Convex and bevel edges behave differently under pressure, respond to maintenance in unique ways, and suit different service menus. This guide explains the differences so you can match the edge to your Australian clientele and choose the right sharpening schedule.
1. Edge anatomy in brief
- Convex edge (Hamaguri-ba): curved grind that tapers from spine to edge, polished for a razor-like finish.
- Bevel edge: flat bevel at the cutting line; often paired with micro-serrations on the straight blade for grip.
- Hybrid edges: some shears combine a convex edge with micro-serrations or a semi-convex (a softened bevel) for durability.
The straight blade’s finish (polished vs serrated) and the toothed blade’s edge type work together to create the feel of the shear.
2. Convex edges — characteristics
| Attribute | Details |
|---|---|
| Feel | Smooth, silent cut with minimal push; ideal for slide work and precise finishing. |
| Steel | Often higher hardness (60–62 HRC, e.g., VG10, ATS-314) to hold the keen edge. |
| Techniques | Slide thinning, dry detailing, curl polishing, advanced texturizing. |
| Pros | Superior glide, less effort, cleaner finish. |
| Cons | Edge rolls if dropped; requires specialist sharpening every 3–6 months in busy salons. |
Convex blades pair naturally with stepped teeth or U-grooves for soft results. Many premium Japanese models (Yasaka, Joewell, Hikari) use convex edges on thinning shears.
3. Bevel edges — characteristics
| Attribute | Details |
|---|---|
| Feel | Slightly more resistance; excellent grip, especially when paired with micro-serrations. |
| Steel | Often mid-range hardness (56–59 HRC, e.g., German chromium steel, 440C) to balance durability and service ease. |
| Techniques | Shear-over-comb blending, heavy-duty salon environments, apprentice training. |
| Pros | Robust, forgiving, tolerant of minor knocks; slower wear; more affordable. |
| Cons | Not suitable for slide thinning or delicate curl work; rougher finish if overused. |
Bevel edges shine when you need reliability and durability, especially in high-volume barbershops where tools may be knocked or shared.
4. Straight blade micro-serrations
Many bevel-edged thinning shears add micro-serrations to the straight blade. Benefits include:
- Better grip during shear-over-comb (particularly for men’s fades).
- Prevents hair from slipping on fine or oily textures.
- Slightly noisier action and not suited to slide thinning.
If you frequently blend fades, keep at least one micro-serrated straight blade in your kit.
5. Match edge to technique and clientele
| Technique / Service | Recommended edge | Notes |
|---|---|---|
| Slide thinning / curl detailing | Convex | Needs smooth glide and minimal resistance; bevel can snag. |
| Shear-over-comb fades | Bevel with micro-serration | Grip keeps sections controlled; pair with 35–40 tooth V-groove. |
| Dry finishing (face frames, fringes) | Convex | Delivers whisper-soft results on fine hair. |
| High-volume salon, apprentice training | Bevel / semi-convex | Durable, easier to service, cost-effective. |
| Chemical-treated hair | Convex preferred | Lighter pressure reduces risk of cuticle damage. |
Use the guide alongside our shear-over-comb tutorial and advanced slide thinning guide when planning education sessions.
6. Maintenance & sharpening
| Edge | Sharpening frequency | Technician requirements |
|---|---|---|
| Convex | Every 3–6 months (busy salons) | Specialist with Japanese-style equipment; ensure they polish the ride line. |
| Bevel | Every 6–9 months (depending on use) | Many service providers can maintain bevel edges. |
| Micro-serrated | Replace serrations only with manufacturer-approved technicians; improper servicing removes serrations. |
Document service history in your salon SOP. Convex edges dull quietly—schedule maintenance proactively rather than waiting for tugging.
7. Buying checklist
- Audit service mix – if your menu is heavy on fades, keep at least one bevel/micro-serrated tool. For curl-focused work, invest in convex edges.
- Ask about sharpening – confirm your preferred technician can service the edge type before purchase.
- Test the glide – perform dry passes on mannequin hair; feel for push or resistance.
- Consider backup tools – keep a convex set for precision tasks and a bevel set for daily blending.
- Review warranty – premium convex shears often include service packages or discounted sharpening through distributors like Japan Scissors.
8. FAQ
Can I slide thin with bevel-edged thinning shears?
Not recommended. Bevel edges with micro-serrations are likely to snag. Switch to a convex-edge shear for slide work.
Do convex edges always cost more?
Generally yes, due to higher-grade steel and specialised manufacturing. However, the smoother finish and reduced fatigue often justify the investment for senior stylists.
Should apprentices start with convex edges?
Only once they have consistent technique. Bevel edges withstand learning mishaps better.
9. Next steps
- Review your current shear set and label each edge type for easy identification.
- Align sharpening schedules with the maintenance checklist to keep edges performing.
- Share this guide during team meetings to reinforce tool selection logic.
- Update the knowledge base with any brand-specific edge details you discover through supplier training.
Understanding edge geometry ensures every thinning shear in your kit delivers the feel and control you expect. Combine these insights with tooth geometry knowledge to fine-tune your cutting arsenal.