Technical Performance Criteria Under The Sharpener Standard™

Acceptable sharpening outcomes are governed by measurable technical criteria, not subjective opinion or method preference.

This page defines the technical principles, measurement standards, and performance expectations that govern work under The Sharpener Standard™.

Core Technical Principles

Principle 1: Geometry Preservation

Acceptable outcomes maintain or restore the tool's intended edge geometry without uncontrolled material removal or structural compromise.

What this governs:

  • Edge angle consistency along the cutting surface

  • Convex profile integrity (where applicable)

  • Apex centralization and alignment

  • Blade set and tension relationships

Measurement standards:

  • Angle deviation: ±2° maximum across blade length

  • Profile consistency: Measurable through comparative inspection

  • Alignment verification: Visual and functional testing

Failure indicators:

  • Flattening of intentional convex profiles

  • Uneven bevels or geometry drift

  • Loss of blade set or tension

  • Asymmetric grinding patterns

Principle 2: Thermal Integrity

Acceptable outcomes preserve the tool's factory heat treatment without thermal damage from sharpening processes.

What this governs:

  • Prevention of heat-induced hardness loss

  • Maintenance of steel temper specifications

  • Avoidance of microstructure degradation

Thermal limits:

  • Steel surface temperature must not exceed tempering threshold (typically 120-150°F depending on alloy)

  • No visible heat discoloration (bluing, tinting, or oxidation patterns)

  • No spark generation as standard practice

Failure indicators:

  • Heat tinting or discoloration on cutting edge

  • Softening evidenced by rapid edge degradation

  • Sparking during sharpening process

  • Premature edge failure in use

Principle 3: Surface Integrity

Acceptable outcomes produce edge surfaces appropriate for intended use without microscopic damage that compromises performance or longevity.

What this governs:

  • Surface finish quality relative to tool application

  • Absence of grinding artifacts that create failure points

  • Edge durability under normal use conditions

Evaluation criteria:

  • Visual inspection under magnification (minimum 10x)

  • Tactile assessment of edge consistency

  • Performance testing under documented conditions

Failure indicators:

  • Visible grinding scratches perpendicular to edge

  • Micro-chipping or edge fracturing

  • Rough or inconsistent surface texture

  • Wire edge or burr remnants

Principle 4: Functional Performance

Acceptable outcomes restore reliable cutting function under normal use conditions without requiring excessive force or creating user safety risks.

What this governs:

  • Cutting efficiency appropriate to tool type

  • User ergonomics and force requirements

  • Stability and control during operation

Performance standards:

  • Tool completes intended work without excessive force

  • No pulling, catching, or instability during use

  • User can maintain natural posture and grip

  • Cutting action is consistent along blade length

Failure indicators:

  • Requires compensatory force or technique

  • Creates hand fatigue or repetitive strain

  • Catches, pulls, or deflects during normal use

  • Inconsistent cutting performance

Documentation Requirements

All work governed by the Standard requires documentation sufficient to demonstrate compliance with technical criteria.

Pre-Work Documentation

Before beginning work, document:

  • Tool condition assessment (geometry, damage, wear patterns)

  • Identified issues requiring correction

  • Limitations or constraints on work to be performed

  • Refusal of work that cannot meet Standard criteria

Post-Work Documentation

After completing work, document:

  • Work performed and methods used

  • Measurements or tests confirming acceptable outcomes

  • Any remaining limitations or recommended follow-up

  • Warranty or guarantee terms (if applicable)

Failure Documentation

When outcomes fail to meet criteria, document:

  • Nature of failure and root cause

  • Remediation attempted or refused

  • Customer notification and resolution

  • Withdrawal of work from service if necessary

Measurement & Verification Methods

Technical criteria may be verified through multiple methods. Specific tools and techniques may vary based on context and available equipment.

Thermal verification:

  • Surface thermometers (contact or infrared)

  • Visual inspection for heat indicators

  • Comparative hardness testing (when appropriate)

Surface quality verification:

  • Magnification (minimum 10x recommended)

  • Tactile assessment by experienced practitioner

  • Performance testing under controlled conditions

Functional verification:

  • Standardized cutting tests (paper, hair, tissue)

  • User feedback under supervised conditions

  • Force measurement (when equipment available)

  • Documented field performance

Geometric verification:

  • Angle gauges and protractors

  • Comparative visual inspection

  • Digital photography with reference standards

  • Specialized edge geometry tools

Common Technical Failures & Root Causes

Technical criteria may be verified through multiple methods. Specific tools and techniques may vary based on context and available equipment.

Thermal Damage

Common causes:

  • Excessive pressure on grinding surface

  • Insufficient cooling or lubrication

  • High-speed power equipment without thermal control

  • Prolonged contact in single location

Prevention: Monitor surface temperature, use appropriate cooling methods, limit contact time, avoid excessive pressure

Over-Sharpening

Description: Excessive material removal creating fragile or unstable edge

Common causes:

  • Misunderstanding of "sharp" vs. "durable"

  • Chasing perfection beyond functional requirements

  • Attempting to correct previous poor work

  • Lack of stopping criteria

Prevention: Define acceptable outcome before beginning, measure material removal, prioritize durability over maximum sharpness

Edge Instability

Description: Edge that fails quickly under normal use despite appearing sharp

Common causes:

  • Over-thinning without structural support

  • Improper apex geometry (too acute for application)

  • Surface damage from aggressive abrasives

  • Thermal damage weakening steel structure

Prevention: Match edge geometry to use case, maintain appropriate apex angle, preserve steel integrity

Convex (Hamaguri) Shears

Critical criteria:

  • Preserve convex profile without flattening

  • Maintain ride line integrity

  • Verify cutting action along full blade length

  • Ensure proper blade set and tension

Common failures:

  • Flattening convex to flat bevel

  • Removing ride line contact surface

  • Creating uneven convex radius

  • Over-tightening or loosening tension

Tool-Specific Considerations

Different tool types have specific technical requirements that govern acceptable outcomes.

Beveled Shears

Critical criteria:

  • Maintain consistent bevel angle

  • Preserve blade set relationship

  • Ensure clean apex formation

  • Verify tip alignment and function

Common failures:

  • Angle inconsistency along blade

  • Rounding of intended flat bevels

  • Tip damage or misalignment

  • Burr or wire edge at apex

Clipper Blades

Critical criteria:

  • Maintain hollow cutting surface geometry

  • Preserve tooth geometry and spacing

  • Ensure proper tension and alignment

  • Verify smooth cutting action

Common failures:

  • Creating crowned or uneven surfaces

  • Damaging tooth geometry

  • Improper tension adjustment

  • Heat damage from high-speed grinding

Geometry Drift

Description: Unintended change in edge angle or profile during sharpening

Common causes:

  • Inconsistent hand pressure or technique

  • Improper tool positioning or setup

  • Excessive material removal

  • Lack of reference measurements

Prevention: Establish geometry baselines before work, measure frequently during process, use consistent technique

When Technical Standards Cannot Be Met

Not all tools can be restored to acceptable standards. Recognition of unrecoverable conditions is part of technical competence.

Refusal Criteria

Work should be refused when:

  • Structural damage prevents safe geometry restoration

  • Previous poor work has compromised steel integrity

  • Tool design or manufacture prevents acceptable outcomes

  • Customer expectations exceed technically achievable results

  • Required work would violate thermal or structural principles

Disclosure Requirements

When limitations exist, practitioners must:

  • Document why acceptable outcomes cannot be achieved

  • Explain technical constraints to customer

  • Offer alternative solutions (replacement, different approach)

  • Refuse to perform work that will fail Standard criteria

Continuing Technical Education

Technical knowledge evolves. Accredited practitioners are expected to maintain current understanding of:

  • Steel metallurgy and heat treatment principles

  • Edge geometry and cutting mechanics

  • Tool-specific design and manufacturing variations

  • Measurement and verification techniques

  • Failure analysis and root cause investigation

The Standard does not prescribe specific training sources but expects documented technical competence appropriate to work performed.

DOCUMENT REF: TSS-TECH-PERF-2.0-2026
GOVERNED BY: The Sharpener Standard™ (Independent Framework)
TECHNICAL FRAMEWORK DEVELOPED BY: Battle Born Blade Sharpening Institute | Nevada City, CA
STATUS: Frozen upon publish — amendments by formal review only