Allen bolts have similar mechanical properties as hex bolts in terms of application and strength however they are manufactured following the DIN912 standard that determines the head and cap size of Allen bolts based on the bolt diameter. in general, the real advantage of Allen bolts over hex bolts is the easier way of fastening and opening them since the driver head is place properly within the hole of Allen bolts as opposed to the hex bolts that the driver is bound to slip from the edge of the bolt. both types of industrial bolts hex and Allen bolts are fastened along with standard DIN934 hex bolts following the grade of bolt.