The whole of the machining in the model below was done on a DRUMMOND 4-in. Lathe. Every part, including such small details as bolts and nuts, were made by the constructor, in preference to buying ready-made. The patterns for the castings were made on the same  lathe. The cylinders are of cast  iron, turned from the solid bar, while the crank-case is of aluminium. Where the parts were too large to swing in the lathe, they were  machined by various rigs, bolting to the boring table, etc, The extremely fine finish on the whole engine is a testimony to the skill of the maker, and also to the qualities of the lathe.
    The weight of the complete engine is 111/2 lb. when fitted with propeller, and it delivered on test 4.6 B.H.P. at 5,800 revs. per min., a truly wonderful performance. The bore of the cylinders is 11/4 inch, and the stroke 11/2 inch.
As one instance of the extremely fine machining in this model, we may mention the master ring, into which the connecting rods are assembled. This was machined from a piece of steel weighing at the commencement 31/2  lb., but when finished weighed only 21/4 oz. It is a very fine example of turning. The maker remarked that even in turning the larger parts the lathe was quite free from chatter.
    This model was shown at the Model Engineering Exhibition in 1914, when it obtained the "Sir Francis Spring" prize.