IN the accompanying illustrations two types of reamers are shown which should prove very useful in the workshop. The form shown in Fig. 1 is known as a floating reamer, the cutting portion being connected to the shank by means of a knuckle joint. The writer recently had a number of gear wheels to bore to a finished size of 1% • inches. The hole was roughed out with a 1 7/64-inch drill, after which the floating reamer was used to bring the hole to size. The reamer shank is tapered to fit the tail stock, while the shank and the reamer are coupled together by means of a tapered pin indicated at A. This reamer was in constant use for ten days and gave excellent service. The expanding reamer shown in Fig. 2 is notable for its simplicity of construction. Unlike the majority of expanding reamers, this reamer permits one to ream down to the bottom of a blind hole, as there are no projections beyond the front face. It has been found that Fig. 2.—An expanding reamer. with machine reamers there is an advantage in having a slight clearance behind the cutting edges, hence the reamer illustrated herewith is provided with such clearance. The shank of the reamer is indicated by the letter O. It is provided with a taper of 30 degrees at the end. Upon this shank is a lock nut A which may be turned by means of a spanner wrench. The cutter proper is indicated at B. This also is provided with flats for a spanner wrench, and there are six saw cuts in it, so that it can be expanded. In adjusting this reamer it will be found that the front cutting edge is expanded slightly more than that at the rear, so that it is possible to obtain a clean parallel hole.