The tooth geometry inside a thinning or texturizing shear determines how much hair you remove, how cleanly the cut finishes, and which techniques feel predictable. Tooth count alone never tells the whole story—spacing, notch depth, and edge finish all contribute to the result. Use this guide to decode the most common tooth profiles, estimate cut rates, and match geometry to Australian hair types and climates.
1. Quick comparison
| Profile | Typical spacing | Notch depth | Cut rate (guideline) | Finish | Best for |
|---|---|---|---|---|---|
| U-groove blender | 0.8–1.2 mm | Shallow | 10–20% | Soft, diffused | Fine hair polish, curl refinement |
| V-groove blender | 1.0–1.4 mm | Medium | 20–30% | Crisp grip | Everyday blending, men’s fades |
| Flat-top (grooveless) | 0.6–0.9 mm | Minimal | 5–12% | Ultra-soft | Fringe detailing, micro polishing |
| Stepped / tiered texturizer | 1.4–1.8 mm | Multi-level | 25–40% | Varied separation | Lived-in texture, curly interiors |
| Chunker (deep V) | 2.0–2.5 mm | Deep | 40–60% | Bold separation | Debulking dense straight hair |
Cut rate ranges reflect medium tension on dry hair. Larger sections, wetter hair, or additional pressure raise removal percentages. Always test on a small subsection before committing to a full panel.
2. Anatomy refresher
Each tooth includes:
- Tip – engages the hair first; sharper tips create crisp entry for precise weight removal.
- Spacing – the gap between teeth. Wider spacing captures more hair and leaves visible texture.
- Notch depth – how far the tooth scoops toward the straight blade. Deeper notches hold more hair and produce stronger removal.
- Micro-steps/grooves – stepped teeth break the contact point into multiple ledges, softening the release.
On the opposing blade, micro-serrations or polished convex edges either grip or glide the hair. Pair geometry with the right straight blade finish: micro-serrated for fade control, high-polish for slide work.
3. Tooth profiles in detail
U-groove blenders
- Rounded channel that guides hair gently toward the straight blade.
- Lower cut rate and whisper-soft finish, ideal for fine or fragile hair.
- Works well for face frames, fringes, and curl polishing where harsh lines must be avoided.
V-groove blenders
- Sharper channel holds hair firmly, giving you grip on straight or dense textures.
- Predictable for scissor-over-comb blending and clean-up passes in men’s grooming.
- Pair with vertical insertion to avoid horizontal lines.
Flat-top (grooveless) teeth
- Minimal notch depth means only a small ribbon of hair enters each tooth.
- Perfect for finishing work on camera-ready looks or smoothing perimeter inconsistencies.
- Requires immaculate tension balance—any slack and the blades may push hair instead of cutting.
Stepped or tiered texturizers
- Multiple ledges across each tooth stagger hair removal for airy, lived-in results.
- Choose stepped designs for curly or wavy hair where you need movement without frizz.
- Limit passes to avoid removing too much in one area; three controlled passes max is a safe rule.
Deep V chunkers
- Aggressive geometry that removes a large volume quickly.
- Reserve for internal debulking on dense, straight hair or corrective work after chemical services.
- Keep at least 4 cm from the perimeter to protect outline strength.
4. Spacing, notch depth, and cut rate estimation
A practical way to predict removal is the S-N-R framework:
- Spacing – measure the gap at the widest point. Sub-1 mm gaps are blending territory; 1.5 mm+ indicates texturizing.
- Notch depth – deeper channels hold greater bundles. Compare teeth side-on under strong light.
- Result – combine with section size to forecast removal. For example:
- 1.0 mm spacing + shallow notch + 2 cm section ≈ 15% removal.
- 1.6 mm spacing + stepped notch + 3 cm section ≈ 35% removal.
Keep a reference card at the cutting station with your most-used shears. Record real-world observations (hair type, passes, visible outcome) to fine-tune predictions.
5. Match geometry to Australian hair types & techniques
| Hair type | Preferred profile | Technique notes |
|---|---|---|
| Fine/fragile | Flat-top or 40-tooth U-groove | Work mid-shaft to ends; single pass prevents collapse. |
| Medium straight | 30–32 tooth V-groove | Vertical insertion, progressive closing for seamless blends. |
| Dense coarse | 24–28 tooth stepped | Elevate sections to 70°+ and distribute passes to avoid heavy panels. |
| Curly/wavy | Stepped U/V hybrid | Focus on mid-lengths; keep 5–7 cm off the scalp to preserve curl spring. |
| Men’s fade | 35–40 tooth V-groove with micro-serrated straight blade | Use reverse orientation (Gyakuba) against the comb for clean transitions. |
Factor in climate. Humidity in Queensland and New South Wales inflates cuticle width, so lean toward softer profiles and lighter pressure. Dry climates in South Australia and Western Australia tolerate a firmer bite but watch for static—comb with anti-static sprays before blending.
6. Maintenance considerations
Different teeth need different servicing approaches:
- U- and flat-top teeth: any burr shows immediately. Schedule specialist sharpening every 3–4 months in busy salons.
- Stepped teeth: demand a technician who can preserve each ledge. Confirm experience before sending tools away.
- Chunkers: inspect for bent tips after each service; even minor knocks cause snagging.
Revisit our thinning shears maintenance checklist for daily oiling and tension routines that keep geometry performing as designed.
7. Buying checklist & tool audit
- Identify gaps – list tooth profiles in your drawer, note where results fall short.
- Test before buying – request demo tools from trusted suppliers (Japan Scissors, Excellent Edges) and trial on mannequins.
- Record cut rates – log expected vs. actual removal in the client record to build a salon-specific database.
- Balance ergonomics – lighter handles and offset grips reduce fatigue during repeated blending passes.
- Plan for servicing – set calendar reminders for sharpening based on tool usage rather than waiting for performance drops.
8. FAQ
Do more teeth always mean a softer result?
Generally yes, but spacing and notch depth influence removal just as much. A 30-tooth blender with wide spacing can cut more than a 24-tooth stepped texturizer depending on geometry.
Can I slide thin with V-groove teeth?
Only if the straight blade has a polished convex edge and the shear is freshly serviced. Otherwise, use stepped or U-groove teeth to avoid snagging.
How do I explain geometry to clients?
Keep it simple: describe whether you’re “softening” or “creating movement”, and show the tool briefly so clients understand the plan.
9. Next steps
- Audit your existing shears using the S-N-R framework and fill any profile gaps.
- Update your salon SOP with geometry notes alongside the training pathway and slide thinning guides.
- Share this article with apprentices before advanced cutting blocks so they learn consistent terminology.
- Capture before/after images of different tooth profiles for internal training decks and future case studies.
Understanding tooth geometry transforms thinning from guesswork into repeatable craft. Combine these insights with the rest of our technique library to deliver consistent, confidence-building results across every Australian salon chair.