Description

Bolt 8UN -1.3/4″ X 6.5/8″

This bolt is 8UN

Diameter 1.3/4″

TPI 8

Length from under the hex head 6.5/8″

Total length 8″

www.britishpipeclamps.co.uk

Part number stamp E129A

This bolt is New / Old stock, may show some signs of age but perfectly good to use.

Understanding The Grading Of Bolts

When purchasing high tensile bolts, there are two main grades you should be aware of: ‘S’ and ‘8.8’ Many times, two fasteners and fixings look and feel the same, and there’s a reason why.
· 8.8- This type of grade is often referred to as the structural grade for bolts. These types of bolts often have galvanised hexagon heads, and most are made with zinc or are zinc plated. To identify this grade, look out for an ‘8.8’ stamp or a set of three radial lines on the head of the bolt. Most often, customers looking for a high tensile bolt may just be looking for the 8.8 grade.
· S- An S grade refers to the tensile strength of industrial fasteners, or the maximum amount of stress these fasteners and fixing can withstand before they begin to break or fail. When a bolt has a grading of S, it means that it can withstand a stress of 45 to 49.9 metric tonnes per 6.45 cm². This grading, which is typically stamped on the head of the bolt, has the same tensile strength as a grade 8.8 bolt.

Bolts labelled with the grade 8.8 or S are solid, heavy duty bolts that can be used for a variety of tasks. However, it is important to understand that other grades are also available, although perhaps not used as often.
· 4.6- These types of bolts are considered to be commercial grade and are not as strong as an 8.8. In vehicles, they are often used to hold light objects like trim. Most customers will not need this type of bolt except in circumstances where strength is not an issue.
· 12.9- These fasteners and fixings are meant for the heaviest jobs, like securing engines and ensuring drives are tamper proof.
· R- This grading can withstand 40.8 to 45 metric tonnes per 6.45 cm², and while it used to be popular, it is now quickly being replaced with the more common and efficient S grade.