M14 X 45 Hex Head Bolt 10.9 DIN931 Self Colour

These 10.9 high tensile hexagon head bolts DIN 931 are part thread and the remainder of a bolt is a smooth shank in-between the bottom of the hexagon head and the beginning of the thread where-as hexagon set screws DIN 933 are full thread .  The length of the shank and the thread vary to a formular depending on the size of the bolt. Tightening strength and torque is worth checking for critical applications to prevent movement of the material under certain stress conditions.

It is important to get the correct tensile strength for the application its being used for as either a higher tensile strength or lower tensile strength may be suitable.  These are usually stamped on the head of the set screw or bolt.  Having a higher tensile strength may not always be suitable on certain applications as movement and stretching of the materials being joined together or the breaking point could be important so always check suitability for specific applications.  Once the fastener has been disassembled it’s advisable to replace all components such as the fastener nuts and washers together with the set screws or bolts.  The reason is that the fastener over time will experience stretching of the threads of when it was tightened up plus the likely constant movement may cause fractures causing weakness to the fastener.

These are self colour fasteners which have no corrosion protection so ideally needs coating with paiting or plating.  Easier to weld that plated fasteners. 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 its always worth checking with a manufacturer's specifications or drawings if an alternative size, tensile strength or types of nuts and washers are used.