timber half-wrought for sporting rifles

IS 7549: Scope - Key Specifications & Tables

• Scope: Covers dimensions, tolerances, and definitions related to half-wrought steel products.

• Rounding off (Clause 0.4):
  Final test/analysis values must be rounded per IS 2-1960, matching the decimal places of the specified value.

• Definitions (Clause 2.1):
  Uses definitions from IS 707-1968 plus additional ones specific to this standard.

• Dimensions & Tolerances (Clause 5.2):
  Permissible tolerances for half wrought steel products:

Summary

• Use IS 2-1960 for rounding off results.
• Follow IS 707-1968 for definitions.
• Apply tolerances as per Table 5.2 for manufacturing and quality control.

flowchart TD
    A[Start: Product Measurement] --> B{Check Dimension}
    B -->|Length| C[Apply +50 mm tolerance]
    B -->|Thickness| D[Apply +13 mm tolerance]
    B -->|Width| E[Apply +25 mm tolerance]
    C & D & E --> F[Round off per IS 2-1960]
    F --> G[Verify compliance with IS 7549]

This ensures dimensional accuracy and standard compliance for half wrought steel products.

IS 7549 - Definitions Summary

• The standard refers to definitions in IS 707:1968 for foundational terms related to the subject.
• Rounding of test or analysis results must follow IS 2:1960, maintaining the same number of significant figures as specified values.
• No direct formulas or tables are given under "Definitions" in IS 7549; refer to IS 707 for detailed definitions.
• Contact details and branch offices of BIS are provided for further reference or clarifications.

Key Points:

Important Reference:

• IS 707:1968 — For detailed definitions related to this standard.
• IS 2:1960 — For rules on rounding off numerical values.

If you need specific definitions or formulas, please refer to IS 707 or specify the term for detailed explanation.

IS 7549: Material Requirements Summary

1. Timber Species (Clause 3.1, Table 1)

Half-wrought wooden members (butt and fore-ends) shall be from the following species:

2. Dimensions & Tolerances (Clause 5.1 & 5.2, Table 5)

• All dimensions are in millimeters.
• Grain direction is parallel to the specified edge.

3. Rounding Off (Clause 0.4)

• Test results or calculations shall be rounded as per IS 2-1960.
• Retain the same number of significant figures as the specified value.

flowchart LR
    A[Material: Timber Species] --> B[Manufacture Half Wroughts]
    B --> C[Check Dimensions]
    C --> D{Within Tolerances?}
    D -->|Yes| E[Accept Material]
    D -->|No| F[Reject / Rework]

This ensures compliance with IS 7549 material specifications and quality control.

IS 7549 – Quality and Defects: Key Points

1. Tolerances (Clause 5.2)

• No negative tolerance is allowed (Clause 5.3).

2. Quality Specifications (Clause 4.1)

• Moisture content ≤ 20%.
• Grain slope ≤ 1 in 15.
• Free from:
  • Centre-heart (pith)
  • Decay (rot)
  • Dead/live knots
  • Checks, shakes, splits
  • Borer holes
  • Warp or any other defects except those permitted.
• Plugging defects is not allowed.

3. Permissible Defects (Clause 6.1)

• Only defects explicitly permitted under Clause 6.1 are allowed; others must be absent.

4. Rounding Off (Clause 0.4)

• Follow IS 2-1960 for rounding test results.
• Retain the same significant figures as specified.

flowchart LR
  A[Half Wroughts] --> B[Moisture ≤ 20%]
  A --> C[Grain slope ≤ 1:15]
  A --> D[No defects except permitted]
  D --> E[No plugging allowed]
  F[Tolerances] --> G[Length +50mm]
  F --> H[Thickness +13mm]
  F --> I[Width +25mm]

This ensures material quality and dimensional accuracy per IS 7549.

IS 7549: Dimensions and Tolerances for Half Wroughts

1. Dimensions (Clause 5.1)

• Half wroughts must conform to dimensions shown in Figures 1 to 3 (grain parallel to specified edge).
• All dimensions are in millimetres.
• Both broader faces shall be planed (Clause 4.3).

2. Tolerances (Clause 5.2)

3. Rounding Off (Clause 0.4)

• Final measured values must be rounded according to IS 2-1960.
• Retain the same significant figures as specified values.

Summary Table

This ensures dimensional accuracy and uniformity in half wrought products per IS 7549.

IS 7549: Permissible Defects and Treatments for Half Wrought Timber

Key Points from IS 7549:

• No negative tolerance allowed (Clause 5.3).
• Tolerances permitted (Clause 5.2):

• Defect Restrictions (Clause 4.1):

  • Moisture content ≤ 20%.
  • Grain slope ≤ 1 in 15.
  • No center-heart (pith), decay, dead/live knots, checks, shakes, splits, borer holes, warp.
  • Plugging of defects is not allowed.

• Permissible Defect (Clause 6.2):

  • Sapwood allowed up to 20% surface area if:
    • It is sound.
    • Treated prophylactically by dip in-dip out with 10% copper naphthenate solution in white spirit or suitable organic solvent.

Summary Table for Defects & Treatments

Practical Notes:

• Always ensure moisture content ≤ 20% before use.
• Avoid any form of plugging or repair of defects.
• Use specified chemical treatment for sapwood to prevent decay.

flowchart TD
    A[Half Wrought Timber] --> B{Defects?}
    B -->|No| C[Acceptable]
    B -->|Sapwood ≤ 20%| D[Check Soundness]
    D -->|Sound| E[Treatment: Dip in-dip out with 10% Cu Naphthenate]
    E --> F[Acceptable]
    D -->|Not Sound| G[Reject]
    B -->|Other Defects| G[Reject]

This ensures compliance with IS 7549 for quality and durability of half wrought timber.

IS 7549 - Surface Preparation Key Points

• End Coating (Clause 8.1):
  Immediately after inspection, coat ends of accepted half-wrought timber up to 8 cm with moisture-proof compositions:

  • Resin + lamp black (10:1), melted and applied hot, or
  • Hardened gloss oil (per IS 1141:1973).

• Sapwood Treatment (Clause 6.2):
  Sapwood ≤ 20% surface area allowed if sound and treated prophylactically by dip in-dip out with 10% copper naphthenate solution in white spirit or suitable solvent.

• Rounding Off (Clause 0.4):
  Test results rounded per IS 2:1960, maintaining significant digits as per specified values.

• Dimensions (Clause 5.1):
  Half-wrought timber dimensions as per Figures 1-3 (all in mm), with grain parallel to specified edges.

Summary Table: Surface Coating Composition

flowchart TD
    A[Inspection of Half Wrought] --> B{Accepted?}
    B -- Yes --> C[Coat Ends (8 cm)]
    C --> D[Use Resin + Lamp Black or Hardened Gloss Oil]
    B -- No --> E[Reject or Reprocess]

This ensures moisture protection and durability of timber ends per IS 7549.

Protection of Timber Ends as per IS 7549

Key Specifications:

• Sapwood Limitation (Clause 6.2):

  • Sapwood shall not exceed 20% of surface area.
  • Must be sound and treated prophylactically by dip in-dip out with 10% copper naphthenate solution in white spirit or suitable solvent.

• End Coating (Clause 8.1):

  • Immediately after inspection, coat ends up to 8 cm with moisture-proof compositions:
    • (a) Resin and lamp black (10:1) mixed and applied hot, or
    • (b) Hardened gloss oil (per IS:1141-1973).

Species of Timber (Clause 3.1, Table 1):

Summary Diagram:

flowchart TD
    A[Sapwood ≤ 20%] --> B[Treated with 10% Copper Naphthenate]
    C[Half Wrought Ends] --> D[Coated up to 8 cm]
    D --> E{Coating Material}
    E --> E1[Resin + Lamp Black (10:1) Hot Applied]
    E --> E2[Hardened Gloss Oil (IS:1141-1973)]

This ensures durability and moisture resistance at timber ends, critical for sporting arms manufacturing.

IS 7549 - Marking and Identification of Half Wrought Timber

Key Specifications (Clause 9.1 & 9.1.1):

• Mandatory Markings on Each Accepted Half Wrought:

  • Manufacturer's name or trade-mark
  • Year of manufacture
  • Species of timber (refer IS 7549 Clause 3 for species classification)

• Optional Marking:

  • ISI Certification Mark (subject to ISI licensing and quality control regulations)

Purpose of ISI Mark:

• Assures compliance with IS standards under strict inspection and testing.
• Continuous conformity checks by ISI.

Summary Table for Marking Requirements

Additional Notes:

• Marking must be legible and indelible.
• ISI Mark usage governed by Indian Standards Institution Certification Marks Act.
• For ISI license details, contact ISI offices (refer Clause 30.00 addresses).

flowchart LR
    A[Half Wrought Timber] --> B{Marking Requirements}
    B --> C[Manufacturer's Name/Trade-mark]
    B --> D[Year of Manufacture]
    B --> E[Species of Timber]
    B --> F[ISI Certification Mark (Optional)]

For detailed species codes and timber classification, refer to Clause 3 of IS 7549.

IS 7549: Inspection and Acceptance Key Points

1. Tolerances on Dimensions (Clause 5.2)

• No negative tolerance is allowed (Clause 5.3).

2. Rounding of Test Results (Clause 0.4)

• Final test values must be rounded as per IS 2:1960.
• Retain the same number of significant figures as specified in the standard.

3. Post-Inspection Coating (Clause 8.1)

• Ends of accepted half wroughts must be coated up to 8 cm with moisture-proof compositions:
  • Resin and lamp black (10:1 ratio), applied hot.
  • Hardened gloss oil (per IS 1141:1973).

Summary Table:

flowchart TD
    A[Inspection of Half Wrought] --> B{Dimension Check}
    B -->|Within Tolerance| C[Accept]
    B -->|Out of Tolerance| D[Reject]
    C --> E[Coat Ends (8 cm)]
    E --> F[Storage/Dispatch]

This ensures compliance with IS 7549 for dimensional accuracy and protection against moisture.