Shaft Collar Without a Set Screw: Split Halves With a Tapered Thread, Clamped by a Nut (Melius, 1904)

"Ordinary shaft-collars are generally in the form of a continuous ring, and it is necessary to slip the same over the ends of the shaft, and the collar is secured in place by transverse set-screws." "The halves of the part A when arranged upon the shaft do not come in close contact with one another, but are a slight distance apart, so that when the nut C is threaded upon the portion B the halves of the part A will be drawn together and tightly clamped upon the shaft."

Grip 36 mm A/F hex bar in the 3-jaw chuck with 35 mm sticking out. Face the end. Turn the body round to 26.7 mm for 20 mm from the end, leaving the hex as the flange, and chamfer the end 1 mm. Centre-drill, drill through 15 mm and ream 16 mm, or bore to 16 mm; check that the shaft slides through. Part off 28 mm from the end, so the flange is 8 mm thick.

Hold the part by its hex flange in the vice, in soft jaws. Start the 3/4 inch taper pipe die square on the chamfer, in its die stock, and cut the thread up to the flange with cutting oil, backing off every half turn to break the chips. The die cuts the 1 in 16 taper itself: the thread is biggest at the flange.

From the same hex bar, face, centre-drill and drill through in steps up to 23.4 mm (59/64 inch), then part off 14 mm long. Hold it in the vice and run the 3/4 inch taper pipe tap in from one face with cutting oil until part A screws in by hand about half its thread length. Mark the face you tapped from: the larger end of the thread, it goes towards the flange. Deburr both faces.

Blue the flange face and scribe a line across it through the centre, from corner to corner of the hex. Hold the part in soft jaws with the line upright and saw straight down the line, through flange and body, with a fine hacksaw blade. File the saw marks off the cut faces but take no more: the 1 mm gap left between the halves is what lets the nut squeeze them onto the shaft. Deburr the bore and the thread ends.

Slide the nut onto the shaft from its end, marked face first. Put the two halves round the shaft where the collar is wanted, flange towards the face it must bear on, and hold them together. Screw the nut onto the taper by hand, then hold the flange with one spanner and tighten the nut with the other until the halves grip. Try to slide and turn the collar on the shaft; it must not move. To move it, slacken the nut, slide the halves, and tighten again.

**Charles H. Melius** of Gloversville, Fulton County, New York, US 758,549, dated 26 April 1904, filed 2 May 1903. He claimed "a shaft-collar consisting of two longitudinally-divided parts adapted to fit around a shaft, a tapered threaded portion formed on one of the parts and an internally-threaded convex wall formed on the other part", the nut's sections joined by tongue and mortise and a pin. His Figs. 3 and 4 show that halved nut, which goes on without reaching the shaft's end; we build Fig. 1's solid nut. His nut thread is "curved" so its threaded portion is convex; ours is the straight taper of a standard pipe thread. He says the flange may be polygonal for a wrench or have holes for a spanner; ours is hex. The patent gives no sizes; every size here is ours.