The specification details the standards for tower bolts fabricated from non-ferrous metals like brass, aluminium alloy, and zinc alloy. It includes dimensional criteria, material requirements, finishing processes, labeling, packaging, and quality inspection methods to guarantee dependable functionality in architectural hardware applications. This standard is crucial for manufacturers, suppliers, and engineers involved in the design, production, or procurement of non-ferrous tower bolts for doors, windows, and furniture.
Overview
The specification details the standards for tower bolts fabricated from non-ferrous metals like brass, aluminium alloy, and zinc alloy. It includes dimensional criteria, material requirements, finishing processes, labeling, packaging, and quality inspection methods to guarantee dependable functionality in architectural hardware applications. This standard is crucial for manufacturers, suppliers, and engineers involved in the design, production, or procurement of non-ferrous tower bolts for doors, windows, and furniture.
Audience
Contents
Structure
This section defines the coverage including dimensions, essential parameters, and compliance requirements for tower bolts utilized in skeletal framework structures. It also presents a sampling plan and permissible defect limits based on lot sizes.
Lists key Indian Standards referred to within this specification, detailing material grades, properties, and testing methods necessary for manufacturing compliant tower bolts.
Describes the different categories of tower bolts covered, such as barrel and skeleton types, with details on construction materials like brass, aluminium, and zinc alloys, plus the corresponding design features.
Specifies acceptable materials and their grade designations as per Indian Standards, including aluminium alloys, brass sheets and castings, and zinc die cast alloys, ensuring standardized quality.
Details dimensional requirements, tolerances, and construction features for skeleton and barrel tower bolts, including plate thicknesses, bolt diameters, staple numbers, and screw hole provisions.
Provides detailed dimensional measurements and acceptable tolerance ranges for various bolt components, ensuring interchangeability and proper fitment.
Outlines finishing requirements including polishing, plating, anodizing, oxidation, and bronzing for different metal types to enhance durability and aesthetics.
Describes packaging practices to protect bolts during transport and storage, along with marking protocols to include manufacturer details, standard numbers, product grade, and batch information.
Explains sampling sizes relative to lot quantities, permissible defective units, testing procedures, and certification requirements to verify compliance with the standard.
Specifies marking provisions including optional BIS Standard Mark usage and mandatory labeling details to ensure traceability and quality assurance.
Comprehensive listing of Indian Standards referenced throughout the document, providing guidance on material quality, manufacturing processes, and testing methodologies.
Frequently Asked
IS 204 Part 2 (1992) permits the use of several non-ferrous materials for tower bolts as listed in Clause 4.1, Table 3: aluminium alloy tubes (IS 1285:1975, designations 63400 WP or P), aluminium alloy extruded rods (IS 733:1983, designation 65032 WP), brass sheets (IS 410:1977, alloy CuZn 40, condition HB), cast brass (IS 292:1983, grade CB-2), extruded brass (IS 319:1974, type II, half hard), and zinc base alloy die castings (IS 742:1981, alloy Zn A14). These materials ensure appropriate mechanical strength, corrosion resistance, and durability for tower bolt applications.
The standard dimensions and tolerance limits for barrel tower bolts made from brass and aluminium are defined in Table 1 of IS 204 Part 2, Clause 6.1. For example, barrel length ranges between 50 mm to 150 mm with a tolerance of ±1.0 mm, bolt diameters vary from 6 mm to 12 mm with ±0.2 mm tolerance, and plate thickness ranges from 1.5 mm to 3 mm with ±0.1 mm tolerance. Each bolt includes a spring and ball mechanism inside the barrel to ensure smooth operation. Detailed sizes and tolerances should be referenced directly from the standard’s specified table.
Tower bolts require specific finishing processes based on the metal type. Brass barrel bolts (types 1 to 3) should be polished or plated as per buyer requirements. Aluminium alloy bolts (type 4) are to be anodized with transparent or colored coatings conforming to IS 1868:1982 Grade AC 10. Zinc alloy bolts (type 5) may be oxidized, bronzed, or plated. Similarly, skeleton tower bolts made of brass (types 6-7) must have bright finishes, aluminium alloy (type 8) anodized per IS 1868, and zinc alloy (type 9) treated with oxidation or plating. Sheets thicker than 1.2 mm must have countersunk screw holes, and all sharp edges should be removed to prevent defects.
Sampling for quality inspection follows the plan outlined in Table 4 of IS 204 Part 2. Lot sizes up to 200 units require a sample of 15 bolts with zero permissible defects; increasing lot sizes correspond to larger sample sizes and allowable defective counts (e.g., 801+ units require 55 samples with up to 3 defective bolts permissible). A lot is accepted if the defective count does not exceed the permitted number. Manufacturers must also provide a certificate of compliance confirming adherence to the relevant Indian Standards. Proper packaging and labeling are essential for maintaining quality during handling.
The standard recommends packaging that protects bolts from damage during transit and storage, although detailed packaging dimensions are not specified. Aluminium alloy bolts should be individually wrapped in tissue paper or polythene film. Each package or carton must be labeled with the manufacturer’s name or trademark, the IS standard number (IS 204 Part 2), product grade or designation, batch or heat number, and quantity. Marking may optionally include the BIS Standard Mark to demonstrate conformity. These practices ensure traceability and preservation of product integrity.
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