M8 x 60 Cup Square Coach Bolt 4.8 DIN603/555 Bzp

Coach bolts formerly known as cup square hex bolts have a curved plain head with a square section below the head so it assists in securing the coach bolt from rotating when in position. These DIN603/555 specification cup square hex bolts are fully threaded up to 100mm in length and there-after there is a smooth shaft between the under-head hex and the thread.  The tensile strength on these are 4.8 which serves a purpose for specific applications. The tightening strength and torque is worth checking for critical applications to prevent movement of the material under certain stress conditions.  They are supplied with class 4 tensile strength nuts.

These are bright zinc plated fasteners which is a preventative measure from corrosion.  Avoid breaking into the bright zinc plating usually abbreviated as Bzp as this will cause faster corrosion if not covered with a corrosive protected material as in time this will weaken the fastener.  Also bear in mind using different materials can cause fusing through corrosion especially in damp conditions when mixed with aluminium or stainless steel materials.

More information is available from Central Fasteners regarding fastener details, but it's always worth checking with a manufacturer's specifications or drawings if an alternative size, tensile strength or types of fasteners are used.