jig at this stage a steel ferrule 30 typically 12 5 or 25 mm long and having internal and external diameters of 1 4 and 1 8 mm respectively is inserted downwardly into the bore 14a of the jig 14 the diameter of the bore 14a is slightly less than the external diameter of the ferrule so that upon insertion of the ferrule the ferrule is gripped by the jig with the hypodermic needle 24 still in position in the jig epoxy resin 31 is introduced from a syringe not shown into the annular space between the ferrule and the needle a length of sheathing is stripped from the end of a plastic sheathed optical fiber 32 for instance by means of a hot coil of resistance wire and then the stripped end 33 is inserted into the hypodermic needle 24 until the sheath comes to rest against the needle tip as seen in fig3 the needle and optical fiber are then lowered together until the sheath enters a certain distance into the ferrule at this stage the level of the resin is preferably at the point of overflowing next the hypodermic needle is fully removed from the jig a small fillet 40 of resin is dispensed around the point of emergence of the sheath from the ferrule to provide additional strength at this region and then the resin is.