Drill Jigs

As a response to requests from builders we have introduced a number of drill jigs. These have been designed to assist in positioning critical bolt holes for reinforcing bushes. One of the most difficult tasks is drilling holes through the wing spars and fuselage longerons. An error made here can be very costly!

All the metalwork we manufacture is produced on CNC machine tools which guarantees a high degree of accuracy and hence interchangeability of components. Some of the metal fittings, e.g. the wing attachment and centre section wing attachment plates have rows of holes through which bolts pass into the spar bushings.

It is no simple matter to position a row of holes by eye to better than say 0.25mm or 0.010", pilot drill them, and then enlarge them to 8mm or 12mm to accept the reinforcing bushes. As the metalwork is produced to an accuracy of better than 10 microns in 500mm it is unlikely that an accurate matching up of holes in the wood and metal will be achieved by this method.

Consequently we are producing drill jigs which have been made to the same degree of accuracy as the metal fittings. Holes in the jigs are deliberately left with sharp edges so that when clamped to the workpiece there will be little or no tendency for the surface grain to splinter.

Note, it is not a good idea to use the actual fitting as a drill jig. The holes will become worn and the protective coating removed. For holes which need to be enlarged from 3/16" to 8mm, and from 1/4" to 12mm, concentricity would be difficult to achieve.

Please note, we are always willing to provide special jigs and assembly aids as required.