This article first appeared in Practical Engineering 1940 Vol1 No3. The information within the article is accurate as of 1940. The article provides details of small tools utilised in workshops at the time.
Drilling Taper Holes
A modern and one of the easiest methods of making a taper hole is by the use of a taper reamer drill of the type patented by the Stalker Drill Works, Ltd., of Drill Square, Sheffield 6, and now in use all over the world. The “Stalker" patent taper reamer drills have been on the market for the past 20 years, and have become so well established that they are in use in practically every large engineering shop, motor-car factory and production shop in this country. They have shown themselves to possess many advantages where mass production methods are in operation, and the saving of time is of paramount importance.
As implied by the name, the tool will drill taper holes from the solid in a drilling machine without the necessity for drilling a parallel hole first and then following with a taper reamer. The previous practice of drilling stepped parallel holes and then reamering for larger taper holes is also completely eliminated.
Drills for producing all standard tapers, Morse, Brown and Sharpe, and the pin taper of 1 in 48 are stocked, with straight and taper shanks, while special tapers and dimensions are in frequent demand. The sizes in production range from No. 000000 taper pin, i.e., .078in. diameter at the large end, to diameters of more than 4in. for special purposes.
Although the two operations are combined in one, taper holes can be produced in solid metal at ordinary drill speeds and feeds, without any snatching or special preparation. The design of the drills, with their serrated cutting flutes, is shown in the accompanying illustration.
Shearing Sheet Metal
The sheet metal shearing machine shown in the accompanying illustration, is one of the "Besco" products of F. J. Edwards Ltd., of Euston Road, London, N.W.I. It is designed to enable straight and curved cuts to be made in sheet metal with ease, and two specimen cuts are shown at either side of the base of the machine.
This method of shearing metal represents a big advance on snips or the old-fashioned hammer and chisel method, for the cut is clean and the edges are free from jagged projections. Consequently, the edges require practically no finishing after the required shape has been cut. The design of this machine is extremely simple, and it is easy to operate. The body is of cast steel, and is arranged to be bolted to the bench. The curved blade is operated by means of a lever bar of ample length. The blades are adjustable and can quickly be removed for regrinding or renewing. The machine is available in three sizes— types A, B, and C—with capacities of 14 gauge, 10 gauge and 8 gauge respectively.
Vickers Quick-Change Drill Chuck
The Vickers quick-change drill chuck, which is a product of the English Steel Corporation, Openshaw, Manchester, has been on the market for a number of years and is proving most popular with all classes of engineers. This chuck enables tools to be inserted or withdrawn without stopping or reducing the speed of the machine. It is of simple construction and consists of three main components: the body, the actuating ring, and the collect, all parts being made of steel and suitably heat treated and ground.
The body is provided with a Morse taper shank which fits the spindle of the machine. On the outer surface slides the actuating ring, whilst the bore of the body is designed to take the collet, which has a Morse taper bore into which the drill or tool fits. The drive is transmitted from the body to the collet by means of two driving dogs or keys arranged to slide in slots provided in the chuck body, and controlled by the position of the actuating ring. When the ring is in the bottom or driving position, the two keys are forced inwards and protrude through the body into local cam-shaped recesses formed in the collet and thereby the whole chuck revolves positively as one unit.
To release the collet all that is necessary is to slide the actuating ring to its upper position, which can be done whilst the machine is running. This movement allows the keys to move outward into a circular recess formed in the ring sufficiently to bring them out of engagement with the collet and thus allow it to be withdrawn. The chucks are made in five different sizes in order to accommodate from No.1 to No.5 Morse taper shanks.
Maiden Bolt Pointing and Bolt-End Rounding Machine
The machine is for finishing the ends of bolts and screws which have been cropped off in the forging machine. It is suitable for Whitworth Bolts ranging from 1in. to 1/4in. diameter. The drive is by motor, through endless V-belts, direct to the spindle, no gears being employed. The spindle is made from a solid-steel forging and carries the cutter head at the front end. The cutters are of high-speed steel and suitably shaped to suit the different diameters of bolts. The cutters are adjustable, and templates are supplied to facilitate setting correctly to size.
The cutter head is provided with suitably positioned slots through which the cuttings are ejected, and hardened steel bushes are fitted in the front of the head for positioning and guiding the work. The cutters are moved forward by means of a hand lever, and returned by adjustable spring tension.
The work carrier is adjustable along the bed to accommodate varying lengths of bolts. It is fitted with hardened steel jaws and an adjustable front plate to support and centralise the work. The lubricant is delivered through the hollow spindle direct to the tools and washes away the cuttings.
The Donovan low-voltage lighting unit has been developed for machine tool lighting. The primary can be any A.C. voltage up to 550 volts, and the secondary either 12, 25, or 50 volts. This low voltage eliminates the danger of shock. It simplifies the wiring up of the machine tool because the lighting for the machine tool can be taken from the main motor supply, i.e., 400 volts generally.
Further, by individually lighting machine tools by low-voltage lighting units, it will be found that quite a small lamp placed where the light shines directly on the 1 work increases output and saves light. Low-voltage lamps are also more robust than the standard 230-volt or 110-volt lamps. The removal of the machine tool from place to place is also facilitated, because the lighting unit is part and parcel of the tool.
The Type 850 Ironclad low-voltage lighting unit consists of a robust cast- iron case with screw-on lid, enclosing a 230 v. or 400 v., etc., primary transformer with a 12 v., 25 v. or 50 v. secondary having an output of 50 watts on 50 cycles. A 550 v. rotary double-pole switch serves to connect the transformer to the supply, and is provided with an interlock to ensure that the lid can only be removed with the switch in the "Off" position. The transformer primary winding is protected by two high rupturing capacity fuse cartridges, and two secondary fuse cartridges are fitted for the lamp circuit, the midpoint of the secondary being connected to the earthing terminal. The whole assembly is arranged so that no live metal is exposed when the lid is removed, the input terminals being shielded.
The transformer unit complies in every way with B.S.S. 794 of 1938, and as regards voltage regulation this unit is well within the limits laid down in the specification. Generally, the unit is supplied complete with an adjustable universal steel bracket mounted on top of the transformer unit, and the complete apparatus fixed in a convenient place for the operator of the machine tool.
The Newman Motorised Unit
A great many machines and machine tools are manufactured today as self-contained units. That is to say an electric motor is incorporated—either built-on or built-in—as standard. To power such machines, all that is required is to connect up to the electricity supply. For machine tools not so equipped, Newman Industries, Ltd., are now offering a self-contained motorised Unit designed to drive any cone-pulley machine, and to operate by electric push-button control.
The Newman unit comprises a frame built of twin steel tubular pillars surmounted by steel bearing brackets which carry the ball-bearing countershaft and cone pulley normally supplied. These pillars are secured by a horizontal cross member, the whole welded together to form an elongated H shape upright frame.?The power member is a Newman totally-enclosed fan-cooled A.C. 3-phase 50-cycles motor. This is fixed to a swivel platform, mounted on the cross member, at approximately 3ft. above floor level.
The primary belt is adjusted by swivelling the motor on the cross member; the- secondary belt by two set screws raising or lowering the bearing brackets. The push-button control is fitted on the front of the machine to be driven immediately adjacent the operator's hand. Cumbersome belt-striking gear is dispensed with, and action is instantaneous for starting and stopping.