id: lawnmower-blade-reference
type: reference
title: "Illustrative reference data: Lawnmower blade specifications and maintenance parameters"
shortdesc: Illustrative lookup specifications, sample fastener torque limits, blade tolerances, and maintenance wear criteria for rotary lawnmowers.

intro: >
  This reference topic provides illustrative mechanical specifications, representative torque ranges, and sample replacement criteria for rotary mower blades to demonstrate structured authoring lookup tables.
  These figures are illustrative examples for documentation modeling and do not constitute certified engineering values for any specific machine.
  Always consult the certified service manual and operator documentation provided by your equipment manufacturer for the exact specifications applicable to your model.

tables:
  - title: Illustrative fastener torque and mounting specifications (sample data)
    headers:
      - Component
      - Example Specification / Size
      - Illustrative Torque Range
      - Typical Inspection Interval
    rows:
      - - Blade retaining bolt
        - 3/8"-24 UNF or M10x1.25 Grade 8
        - 50–60 N·m (38–45 ft-lb) [illustrative sample]
        - Every blade change / 25 operating hours
      - - Center mounting hole
        - Round 15 mm or 6-point star
        - Direct fit (zero play)
        - Before every mounting
      - - Spindle adapter keyway
        - 3/16" square key or molded pin
        - Flush fit (no shear distortion)
        - Annual deck inspection
      - - Blade tip-to-deck clearance
        - Minimum 10 mm (3/8 in)
        - N/A (geometry constraint)
        - After blade strike or deck contact

  - title: Illustrative blade wear limits and replacement thresholds (sample data)
    headers:
      - Defect Type
      - Illustrative Limit Threshold
      - Severity Rating
      - Prescribed Action
    rows:
      - - Edge nick or gouge
        - Depth > 2.0 mm (0.08 in) [sample threshold]
        - Moderate
        - Grind out or replace blade
      - - Sail erosion (lift wing)
        - Thickness reduction > 30% [sample threshold]
        - Critical
        - Replace blade immediately
      - - Blade warp or deflection
        - Tip variance > 3.0 mm (0.12 in) [sample threshold]
        - Severe
        - Replace blade immediately
      - - Blade balance offset
        - Imbalance > 1.5 grams [sample threshold]
        - High
        - Re-balance using cone or magnetic balancer

properties:
  - name: Blade material
    type: Carbon Steel
    default: AISI 1060 / 1070
    description: Heat-treated spring steel quenched and tempered to 42–48 HRC for impact resistance without brittleness (sample metallurgical specification).
  - name: Cutting edge angle
    type: Angular Degree
    default: 30° to 35°
    description: Illustrative sharpening bevel maintaining edge sharpness while retaining adequate backing metal against stones.
  - name: Lift profile
    type: Geometry Type
    default: Medium to High Lift
    description: Curvature on the trailing sail that creates air suction for bagging, mulching, or side discharge.

sections:
  - title: Balancing procedure criteria
    content: >
      A freshly sharpened or repaired blade must be verified on a static cone balancer or wall-mounted magnetic spindle.
      If one end dips downward, material must be removed exclusively from the blunt trailing sail of the heavier side, **never** by grinding the cutting bevel or reducing blade length.

notes:
  - type: important
    title: Illustrative sample data notice
    content: >
      All mechanical torque ratings, dimensional clearances, and wear thresholds listed in this reference topic are generic illustrative examples provided exclusively for technical documentation and information typing demonstration.
      Never use generic figures for equipment assembly or maintenance: always verify exact values in your lawnmower manufacturer’s official operator manual.
  - type: warning
    content: >
      Blades with bent tips, cracked steel near the center hole, or sail wear exceeding 30% cannot be repaired or welded. 
      Centrifugal forces at 3,000 RPM can cause catastrophic fragmentation.

related:
  - id: replace-lawnmower-blade
    relationship: task
    title: Replace a lawnmower blade
  - id: information-typing-concepts
    relationship: concept
    title: Information typing in technical documentation