Downloadable Resources
Corrosive Protective Coatings
Approximately 90% of all carbon steel fasteners are plated, coated, or furnished with some other type of supplementary finish. Although the principal reason is to protect against corrosion, such treatments also enhance appearance, control installation torque tension relationships, minimize thread seizing, and assist product identification.
Headmarks
A manufacturer’s brand, usually a letter or symbol on the head of each fastener is mandatory for compliance with the relevant New Zealand Standard.
Design of Bolted Joints
Bolted joints in which strength is the main design consideration, can, in most cases, be more economically designed when a high tensile bolt is used rather than a mild steel bolt. Fewer bolts can be used to carry the same total load, giving rise to savings not only from the cost of a smaller number of bolts, but also machining where fewer holes are drilled and tapped, and assembly where less time is taken.
Coronet Load Indicators
Coronet Load indicators are designed for use with Blacks high strength structural bolts and they provide a simple and accurate aid to tightening and inspection. They can be supplied with galvanized coating for good corrosion resistance
Imperial Hexagon Bolts: Set Screws
Metric 4.6 Tightening Torques
The tightening torque values given in the table serve only as a guide. A k factor of 0.2 has been used which assumes threads are plain finish, burr-free with a light oil coating. It should be noted that these figures are based on the first tightening of single assemblies in isolation.
Metric 8.8 Tightening Torques
The tightening torque values given in the table serve only as a guide. A k factor of 0.2 has been used which assumes threads are plain finish, burr-free with a light oil coating. It should be noted that these figures are based on the first tightening of single assemblies in isolation.
Metric 10.9 Tightening Torques
The tightening torque values given in the table serve only as a guide. A k factor of 0.2 has been used which assumes threads are plain finish, burr-free with a light oil coating. It should be noted that these figures are based on the first tightening of single assemblies in isolation.
Hexagon Nuts and Hexagon Lock Nuts
Correct Use of Jam or Lock Nuts
When a Jam or Lock Nut is to be used. The lock nut must always be assembled on the bolt first and pulled up snug, but not tightened severely enough to produce a high tension in the bolt.
Construction Lock Nuts DIN 980
Tightening of Structural Bolts
The design, fabrication, assembly, and inspection of steel structures using metric high-strength structural bolts and nuts to AS 1252 are covered in AS 4100 - SAA Steel Structures Code which should be referred to for more detailed information.