The 1980 edition of IS 9576 offers detailed recommendations on the mill sawing of timber, covering various sawing machinery, techniques, equipment upkeep, and optimal timber conversion practices. Designed specifically for the Indian timber sector, it assists professionals in enhancing output, preserving equipment, and ensuring superior quality of sawn wood products by addressing local timber processing challenges.
Overview
The 1980 edition of IS 9576 offers detailed recommendations on the mill sawing of timber, covering various sawing machinery, techniques, equipment upkeep, and optimal timber conversion practices. Designed specifically for the Indian timber sector, it assists professionals in enhancing output, preserving equipment, and ensuring superior quality of sawn wood products by addressing local timber processing challenges.
Audience
Contents
Structure
This section explains the scope of the standard, including definitions related to band saw blades such as clearance angle, theoretical kerf width, and sharpness angle. It references IS 707-1976 for further clarifications and specifies rounding off procedures for test results as per IS 2-1960. A detailed table outlines the specifications of band saw blade teeth based on saw width, thickness, pitch, gullet depth, hook angles, and wood density categories. Practical notes emphasize the use of mechanical presses and brazing fixtures for blade upkeep and highlight the importance of selecting correct blade geometry for efficient cutting.
Defines essential terms such as clearance angle (the angle between tooth face and workpiece), theoretical kerf width (width of cut by blade), and sharpness angle (cutting edge angle). It includes a table detailing saw tooth specifications for various saw widths and wood densities, illustrating how hook angles adjust to wood density levels. The section also addresses rounding rules for test results, maintaining significant figures in line with IS 2-1960.
Describes different types of sawing machines, focusing on circular saw machines with heavy cast iron frames, cast iron tables with slots, mild steel arbor shafts with bearings, and pulleys. It details the mounting of circular steel saw blades secured by collars and nuts. The section reiterates key specifications for band saw blades and includes a schematic diagram illustrating the primary components of a circular saw machine.
Outlines the stages of timber conversion, beginning with breaking down logs into manageable sections, followed by further cutting into desired sizes. It emphasizes avoiding logs with excessive taper, shakes, or flutes to reduce wastage and ensure quality. Guidance includes selecting logs carefully, applying efficient sawing patterns, and monitoring moisture content to optimize conversion outcomes.
Focuses on sawing methods such as plain (flat) sawing, quarter sawing, and rift sawing, describing their effects on grain patterns and timber stability. Recommendations for timber handling include proper log positioning, maintaining sharp blades, and careful post-sawing handling to prevent damage and moisture issues. It provides general advice on selecting sawing methods based on timber species and end-use, minimizing kerf width, and optimizing saw speed and feed rates.
Specifies tooth dimensions for band saw blades according to wood density and saw width. It details the sharpening process using a saw sharpening machine equipped with adjustable platforms, grinders, and a pusher mechanism for tooth-by-tooth rotation. Maintenance tips include blade jointing, maintaining correct hook and clearance angles, and regular verification of gullet depth and pitch to ensure cutting efficiency.
Covers specifications for saw blade teeth, highlighting variations in clearance angle, thickness, pitch, and gullet depth relative to wood density and saw width. Describes the sharpening procedure utilizing adjustable grinding equipment and emphasizes the necessity of joining and leveling teeth for uniform cutting loads. It also outlines saw doctoring operations such as setting, leveling, tensioning, and sharpening to prevent binding and excessive kerf.
Lists safety features for band saw blades including blade guards, steel saw guides to prevent deflection, tensioning devices for blade tightness, and heavy cast iron frames for machine stability. It advises adjusting hook and clearance angles in relation to wood density and maintaining blade thickness and pitch to match saw width and wood type. Regular inspections and brazing are recommended to uphold blade integrity.
Emphasizes quality control in sawing by selecting appropriate hook clearance angles, pitch, and gullet depth based on timber density. Highlights the importance of matching blade thickness to saw width and wood species for precise cutting. Maintenance procedures such as regular sharpening and brazing are stressed to preserve blade performance and timber quality.
Includes detailed tables specifying band saw blade tooth dimensions according to saw width and wood density, definitions of key geometric terms (clearance angle, kerf width, sharpness angle), and illustrative figures such as saw tooth diagrams and brazing fixtures. This section assists users in selecting proper blade specifications and understanding tooth geometry for optimal sawing results.
Frequently Asked
Per IS 9576, recommended saw machines include band saw machines and circular saw machines. Band saws are preferred for precise timber conversion with minimal waste, employing species-specific blades and proper saw doctoring practices such as setting, leveling, tensioning, and sharpening. Circular saw machines feature a robust cast iron frame, a machined table with slots, a mild steel arbor shaft with bearings and pulleys, and a circular steel saw blade secured by collars and nuts. Together, these machines facilitate economical and efficient timber sawing.
Plain sawing is advisable when the timber lacks prominent figure or when it is intended for structural uses such as sleepers and scantlings where appearance is less critical. It is favored for its lower cost, reduced waste, faster drying rates, and more acceptable round knot appearance. Plain sawing produces varied grain patterns and is suitable when rapid drying and cost efficiency are priorities. Conversely, quarter sawing is preferred for enhanced dimensional stability and special grain effects.
The standard recommends first jointing the blade teeth to ensure uniform height, then using a saw sharpening machine equipped with an adjustable platform, angle-controllable grinder, and a pusher mechanism that rotates the blade tooth-by-tooth based on pitch. Sharpening angles should correspond to timber density, with hook and clearance angles around 20°/15° for low to medium density woods and 15°/10° for medium to high density species. Tooth dimensions such as thickness, pitch, and gullet depth must align with blade width and wood type to maintain cutting efficiency and blade longevity.
IS 9576 prescribes several safety features including protective metal guards covering upper and lower wheels to shield operators from blade breakage and vibrations, steel saw guides to prevent blade deflection and reduce cutting shocks, adjustable tensioning and straining devices for maintaining blade tightness, and heavy cast iron frames and bases to ensure machine stability and reduce vibration. Additional features include controlled log feeding carriages and stable table and throat plates to minimize operator exposure and enhance safety.
The standard advises sawing logs with large checks parallel to the crack to minimize waste and maximize usable timber. Crooked or tapered logs should be oriented so that bulges face into or away from the saw, never sideways, and are preferably sawn into thin planks about 2.5 cm thick to optimize yield. Thorough inspection for length, girth, and other defects should precede sawing. The breakdown process involves converting logs into cants by vertical sawing before further processing.
Ask AI about any clause, requirement, or provision in IS 9576. Get instant, clause-cited responses powered by our indexed library.
Free tier includes 150 queries (50 AI + 100 Reference) · No credit card required