Hand-sawing of timber - Guide

IS 4423: Scope Summary

• Scope Definition: IS 4423 covers specifications and testing methods for a particular material/product (typically related to glass or similar materials, as per IS 4423 context).
• Rounding Off: Final test or analysis results must be rounded as per IS 2:1960 rules, retaining the same number of significant digits as specified.
• Normative References: The standard incorporates other Indian Standards (e.g., IS 707 for definitions) which are integral to its application.
• Applicability: Ensures uniformity in testing, evaluation, and compliance verification for materials/products covered under this code.

Key Points:

If you want detailed formulas or tables, please specify the material or test type within IS 4423.

IS 4423 - Clause 2: Normative References Summary

• Normative references are Indian Standards cited in Annex A; these form an integral part of IS 4423.
• Users should refer to the latest editions of these standards for compliance.
• For rounding off test or calculation results, IS 2:1960 applies:
  • Round off values to the same number of significant digits as specified.
• Annex B lists the technical committee responsible for the standard's formulation.

Key points on rounding (IS 2:1960):

Usage:

• Always verify referenced standards in Annex A.
• Apply IS 2 rounding rules to maintain consistency in reporting results.

flowchart TD
    A[IS 4423 Standard] --> B[Annex A: Normative References]
    A --> C[IS 2:1960 for Rounding]
    B --> D[Latest Editions of Standards]
    C --> E[Round off numerical values]

This ensures clarity and uniformity in structural testing and analysis per IS 4423.

IS 4423: Terminology and Definitions - Key Points

• Reference Standards:

  • Definitions primarily refer to IS 707 (Timber Terminology).
  • Rounding off numerical values follows IS 2:1960 rules.

• Saw Specifications (Clause 3.15 & Table 4.1.2):

• Key Terminology:
  • Triangular Tooth: Defined in Clause 3.8, typical saw teeth shape.
  • Cutters: Teeth that cut fibers.
  • Raker: Removes cut fibers, acting like a chisel.
  • Sharpening: Filing teeth to maintain cutting efficiency.

Summary Diagram of Saw Components

graph LR
A[Triangular Tooth] --> B[Cutters (fiber-cutting)]
B --> C[Raker (chisel-like)]
C --> D[Sharpening (file teeth)]

This table and definitions help select appropriate saw length based on log diameter for efficient cutting as per IS 4423.

IS 4423: Types of Saws and Their Recommended Uses

Key Table: Saw Length vs Log Diameter (Clause 3.15)

Definitions:

• Set of Saw Teeth (3.14): Teeth bent alternately to widen the cut.
• Triangular Tooth (3.15): Standard tooth shape for cutting wood fibers.
• Raker Tooth: Acts like a chisel to remove cut fibers and clear the kerf.

Sharpening (Clause 6.6 & 10.1.2):

• Use only the recommended file type for sharpening.
• Filing improves cutting efficiency by restoring tooth shape and sharpness.

Summary:

• Choose saw length based on log diameter.
• Tooth types (cutters, rakers) have distinct roles.
• Proper sharpening with correct files is essential for performance.

flowchart TD
    A[Log Diameter] -->|200-300 mm| B[1300 mm Saw with Cutter Teeth]
    A -->|301-600 mm| C[1500 mm Raker Saw]
    A -->|601-1000 mm| D[1800 mm Larger Raker Saw]
    A -->|1001-1400 mm| E[2400 mm Saw (Sharpening)]
    A -->|>1400 mm| F[3000 mm Large Saw]
    B --> G[Cut Fibers]
    C --> H[Chisel action - Fiber removal]
    D --> H

Key Specifications & Formulas for Action of Saws (IS 4423)

1. Saw Length vs Log Diameter (Clause 3.15 & Table 4.1.2)

2. Tooth Setting (Clause 6.6.4.1)

• Setting Tools: Peg-tooth saws use a setting key; raker-tooth saws use hammer and anvil.
• All teeth must have uniform set for smooth cutting.

3. Sharpening

• Required when saw becomes blunt.
• Filing teeth improves cutting efficiency (Clause 3.18).

flowchart LR
    A[Log Diameter] --> B{Select Saw Length}
    B -->|200-300 mm| C[1300 mm Saw]
    B -->|301-600 mm| D[1500 mm Saw]
    B -->|601-1000 mm| E[1800 mm Saw]
    B -->|1001-1400 mm| F[2400 mm Saw (Sharpening)]
    B -->|>1400 mm| G[3000 mm Saw (Sharpening)]
    
    C & D & E --> H[Cut Fibers & Remove Chips]
    F & G --> I[Sharpen Teeth]
    
    I --> J[

IS 4423: Maintenance of Two-Men Cross Cut Saws (Peg-Toothed Type)

Key Requirements (Clause 6.5 & 6.6)

• Keep cutting edges clean, rust-free, and well-sharpened (6.1).
• Use specified tools for maintenance and sharpening (6.5.2.1).

Tools Required (Table 6.5.2.1)

Recommended Maintenance Practices (Clause 6.6)

• Use the wooden vice to hold the saw steady.
• Employ the wooden jointer to ensure uniform tooth height.
• Sharpen teeth with the flat file, maintaining the original tooth profile.
• Regularly clean teeth to remove rust and debris.

flowchart LR
    A[Saw Maintenance] --> B[Clean Teeth]
    A --> C[Sharpen Teeth]
    C --> D[Use Wooden Filing Vice]
    C --> E[Use Wooden Jointer]
    C --> F[Use Flat File (200mm, 21mm wide)]

This ensures efficient cutting performance and prolongs saw life.

IS 4423: Sawing Techniques and Procedures - Key Points

Sawing Equipment (Clause 8.1.4)

• Saw type affects finish quality and percentage out-turn (yield).
• Selection depends on log diameter and saw tooth type.

Saw Length vs. Log Diameter (Clause 3.15, Table summary)

Tooth Setting for Sharpening (Clause 6.6.4.1)

• Peg-toothed saws: Use a setting key.
• Raker-toothed saws: Use hammer and anvil.
• Uniform set for all teeth is essential.

Summary Diagram: Saw Selection Process

flowchart TD
    A[Determine Log Diameter] --> B{Diameter Range}
    B -->|200-300 mm| C[Use 1300 mm Cutter Saw]
    B -->|301-600 mm| D[Use 1500 mm Raker Saw]
    B -->|601-1000 mm| E[Use 1800 mm Raker Saw]
    B -->|1001-1400 mm| F[Use 2400 mm Raker Saw]
    B -->|Above 1400 mm| G[Use 3000 mm Raker Saw]

Note: Proper sharpening and tooth setting are critical for efficient sawing and maximizing timber yield.

IS 4423 - Timber Yield and Out Turn Key Points

1. Percentage Out Turn of Sawn Timber (Clause 8.1.6.1)

2. Factors Influencing Out Turn (Clause 8.1 & 7.3)

• Defects: knots, flutes, twist, uneven surfaces, borer holes, splits.
• Log quality: size, shape, and defects reduce yield.
• Sawing method: affects precision and waste.
• Moisture content: affects shrinkage and conversion losses.

3. Important Notes

• Out turn % = (Volume of usable sawn timber / Volume of original log or sleeper) × 100
• Higher defects → lower out turn.
• Conversion to scantlings generally yields more usable timber than planks due to less thickness.

flowchart LR
    A[Log or Sleeper] --> B{Conversion Type}
    B --> C[Planks]
    B --> D[Scantlings]
    C --> E[Lower % Out Turn]
    D --> F[Higher % Out Turn]

This summary aids in estimating timber yield during conversion per IS 4423.

Common Sawing Defects and Their Causes (IS 4423)

1. Saw Cuts Crookedly (Clause 9.4)

Causes:

• Large setting on one side of the blade.
• Incorrect jointing or filing causing uneven tooth height.
• Unequal tooth point angle and bevel width.
• Low blade tension (especially in bow saws).
• Excessive pressure applied during sawing.

2. Saw Cuts Roughly and Jumps in a Kerf (Clause 9.3)

Causes:

• Occasional teeth are too high.
• Uneven setting of teeth.
• In raker-toothed saws, rakers are too high.

Approximate Percentage Outturn of Sawn Timber (Clause 8.1.6.1)

Notes:

• Defects like knots, flutes, twist, uneven surface, borer holes, and splits reduce outturn.
• Proper blade maintenance (jointing, filing, tension) is critical for quality cuts.

flowchart TD
    A[Sawing Defects] --> B[Crooked Cuts]
    A --> C[Rough Cuts & Jumps]
    B --> B1[Uneven Tooth Setting]
    B --> B2[Incorrect Filing]
    B --> B3[Unequal Tooth Angles]
    B --> B4[Low Blade Tension]
    B --> B5[Excessive Pressure]
    C --> C1[High Teeth]
    C --> C2[Uneven Setting]
    C --> C3[High Rakers]

This summary helps identify causes and expected yield to optimize sawing operations per IS 4423.

IS 4423: General Instructions on Use and Care of Files

Key Tools & Specifications (Clauses 6.5.2, 5.5, 6.5.2.1)

Care of Files (Clause 10.2)

• Keep files clean using a file cleaner.
• Avoid clogging by removing filings frequently.
• Use proper file handles to prevent injury.
• Store files dry and oil lightly to prevent rust.
• Use appropriate files for specific tasks to avoid damage.

Summary Table: Flat File for Shar

IS 4423: Care of Saws – Key Points

1. Maintenance of Saws (Clause 6.5)

• Regular cleaning and inspection.
• Remove oil, grease, or fatty materials using chalk/charcoal and wire brush (Clause 10.2.2).
• Store saws in dry places to prevent rust.

2. Sharpening Practices (Clause 6.6)

• Sharpen teeth to restore cutting efficiency.
• Use proper files; avoid contamination with oil/fatty substances.
• Maintain correct tooth shape (triangular or raker) per saw type.

3. Saw Length & Log Diameter (Clause 3.15, Table 4.1.2)

• Cutters: Cut fibers only.
• Raker: Chisel action, removes fibers and sawdust.

Summary Diagram: Saw Tooth Function

graph LR
A[Cutters] -->|Cut fibers| B[Wood fibers]
C[Raker] -->|Chisel & remove fibers| B

Keep saws clean, sharp, and matched to log size for efficient cutting.

IS 4423 references several Indian Standards (IS) essential for timber and structural engineering. While Annex A of IS 4423 lists these, key related IS codes typically include:

• IS 302: Part 1 — Methods of Test for Timber: Physical and Mechanical Properties
• IS 883 — Code of Practice for Design of Structural Timber in Buildings
• IS 2878 — Specification for Plywood
• IS 1708 — Methods of Test for Timber: Determination of Moisture Content
• IS 3087 — Code of Practice for Structural Use of Timber

Important Notes:

• Always check the latest edition of these standards.
• Rounding off test values must follow IS 2:1960 rules.
• These standards collectively govern timber testing, design, and use in structures.

Summary Table Example

For detailed provisions, consult Annex A of IS 4423 and the latest versions of these IS codes.

IS 4423: Committee Composition - Key Details

Source: Annex B (Foreword) of IS 4423

Composition of Technical Committee (Timber Sectional Committee, CED 9)

• Each member often has an alternate to ensure continuous representation.
• The committee includes technical experts, government officials, industry representatives, and research institute members.

Summary

• The committee is multi-disciplinary, ensuring comprehensive coverage of timber technology.
• No explicit formulas or tables are provided for committee composition.
• The committee structure supports standard formulation, review, and updates.

flowchart TD
    A[Chairman] --> B[Institute of Wood Science]
    A --> C[Ministry of Defence]
    A --> D[Wimco Ltd]
    A --> E[Indian Plywood Institute]
    A --> F[Forest Departments]
    A --> G[Directorate General Technical Dev.]
    A --> H[Ministry of Railways]
    A --> I[Naval Headquarters]
    A --> J[Research Institutes]
    A --> K[Ministry of Environment & Forests]
    A --> L[Supplies & Disposal]
    A --> M[National Test House]