Pencil slats
1989 Edition

Scope (Clause 1.1): Details specifications for pencil slats intended for pencil manufacturing.

Referenced Indian Standards (Clause 2.1):

• IS 1375: Black pencil specifications
• IS 707: Timber technology terminology glossary
• IS 2: Rules for numerical rounding

Timber Species for Pencil Slats (Clause 4.1, Table 1):

Rounding Off (IS 2:1960): Test results must be rounded to the prescribed number of significant figures.

This section ensures correct wood selection and precision in testing for pencil slat production.

The standard refers to key Indian Standards including:

• IS 1375:1959 – Specifications for black pencils
• IS 707:1976 – Glossary of timber technology terms
• IS 2:1960 – Rules for rounding numerical data

All test values must be rounded as per IS 2, preserving significant digits.

The timber species table guides species selection for pencil slats with quality grades I and II.

This section highlights the interlinked standards essential for compliance.

All terminology used in the standard adheres to IS 707:1976, the glossary for timber technology.

The species of timber used for pencil slats are categorized by quality levels I and II as per the timber species table in Clause 4.1.

Final test measurements must be rounded according to IS 2:1960.

This section clarifies the technical terms and classification critical for uniform understanding.

The following timber species are designated for pencil slats production:

Grade I species are preferred for their favorable machining and finishing properties.

This classification is based on research ensuring suitability for pencil slat manufacturing.

Specifications include dimensional tolerances for pencil slats, accounting for green or partially seasoned timber.

• Length and thickness tolerances are fixed with no additional allowances.
• For green or inadequately seasoned wood, extra dimensional allowances are permitted to accommodate shrinkage.

Typical tolerances:

Guidelines recommend using Annex A for sawing to minimize variations and Annex B for waxing/dyeing treatments to stabilize size.

Ensures precision in slat dimensions for manufacturing consistency.

The standard mandates the following for pencil slat quality:

• Rounding of test results must follow IS 2:1960 guidelines.
• Only specified timber species classified as quality I or II are acceptable.

Additional references include IS 1375 for pencil specifications and IS 707 for timber terminology.

This section ensures adherence to species and quality benchmarks necessary for reliable pencil slat production.

Key treatment specifications include:

• Moisture content of slats must not exceed 12%.
• Timber blocks should be air-seasoned prior to final sawing.
• Sawing must allow for oversize in green timber to compensate for shrinkage.

Waxing and dyeing treatments:

• Slats can be treated or untreated.
• Waxing is mandatory to enhance moisture resistance.
• Dyeing is optional for coloration.
• Annex B details both a two-step waxing/dyeing process and a combined single-step method.

This treatment ensures dimensional stability and surface durability for pencil slats.

Bundles of pencil slats must be clearly and permanently marked with:

• Quantity of slats and ply count
• Manufacturer identification (name, initials, or trademark)
• Timber species used
• Treatment status (treated or untreated)
• Year of production

Annex A provides guidelines for sawing and storage to maintain moisture content below 12%, using precise saws and proper stacking.

Annex B outlines waxing and dyeing treatment parameters including wax absorption levels and drying temperatures.

Proper marking ensures traceability and compliance with quality standards.

Every bundle must bear indelible markings indicating:

• Number of pencil slats and ply
• Manufacturer's name, initials, or recognized trademark
• Species of timber used
• Treatment condition
• Year of manufacture

Marking supports traceability and quality control under the Bureau of Indian Standards regulations.

Waxing and dyeing treatments may be conducted in either single or two-step processes with specified wax absorption and vacuum-pressure techniques.

Ensures product identification and regulatory compliance.

Sawing steps:

1. Logs are cut into blocks with allowances for drying shrinkage and desired ply thickness.
2. Blocks are air-seasoned to reduce moisture before final slatting.
3. Precision sawing with band or circular saws minimizes taper.
4. Sawn slats are stacked under restraint to prevent warping.
5. Final moisture content must be 12% or less.

Dimensional oversize allowances are applied for green or inadequately seasoned timber.

Bundles must be marked with all required details for traceability.

This ensures production of slats with accurate dimensions and stable moisture content.

Two treatment methods are specified:

• Two-step process:

  • Dyeing followed by drying to 12% moisture.
  • Wax dipping in molten paraffin at 80-100°C.
  • Wax uptake between 8-15% of dry weight.
  • Final kiln heat treatment at 70-80°C for 12-24 hours.

• Single-step process:

  • Use of wax emulsion mixed with dye.
  • Vacuum-pressure impregnation above wax melting temperature.
  • Final kiln drying and conditioning at 70-80°C.

Wax absorption enhances moisture resistance and durability.

These treatments ensure even wax penetration and surface quality.