the present invention provides for an assembly for locking a first workpiece mountable onto a second workpiece . the first workpiece has an opening adapted to allow a locking pin to pass therethrough . the opening is cooperatively disposed with respect to a pin receiving means in the second workpiece when the first workpiece is mounted on the second workpiece . at least one of the first and second workpieces has a recess to receive a pin carrier . the assembly comprises a locking pin adapted to pass through the opening and be received by the pin receiving means when the first workpiece is mounted on the second workpiece ; and a pin carrier receivable in the recess . the pin carrier has a pin receiving orifice and is alignable with both the opening and the pin receiving means when the first workpiece is mounted on said second workpiece . the assembly further comprises magnetic means on the locking pin and / or the pin carrier to magnetically attract the locking pin and the pin carrier .