This article first appeared in Practical Engineering 1940 Vol1 No25. The information in the article is accurate as of 1940. This article highlights new small tools brought to market and used by Industry at the time.
The U.S. Motorised Plain Miller
An interesting line marketed in this country by the Mortimer Engineering Co., of Acton Lane, London, N.W.IO, is the U.S. plain milling machine. This miller is made by the United States Machine Tool Co., of Cincinnati, and has several novel features.
The milling spindle together with the overarm constitute a head that is vertically adjustable on the column of the machine. A hand lever operating through a rack and gear quadrant moves the milling head vertically on the column, a clamp being provided to lock the head in any position. A counterweight is used to balance the head.
The spindle, of chrome nickel steel, is mounted in taper roller bearings. It has a No. 9 B. and S. taper hole and is driven by a vee-belt from a back shaft, which, in turn, is driven by three-step cone pulleys and vee-belt by a 1-h.p. motor at the rear of the column.
The vertical-and cross-feed motions of the table are effected by screws, provided with micrometer dials, while the longitudinal feed is hand-lever operated. The table has a working area of 23in. by 6 5/8in., and a longitudinal movement of 6in. The cross and vertical movements are 5in. and 15 3/4in. respectively. A lower speed machine is also available. The spindle runs in phosphor bronze bearings and is driven by a flat belt from the back shaft, which also runs in plain bearings.
Several types of machine tool, stands are offered by T. F. and J. H. Braime, Ltd., of Hunslet, Leeds. These have been specially developed for use in workshops and factories, and are robustly constructed to withstand many years of continuous use. The stand consists of three steel trays pressed from heavy gauge material and mounted on steel columns one above the other by means of long bolts passing through the entire assembly.
This method of construction ensures that the complete stand is rigid, but can easily be dismantled and packed into a small space for storage or transport to another site. The stands are mounted on tubular iron legs with pressed steel feet, although there is an alternative design in which the feet are replaced by casters. The caster wheels are of a patent design whereby the caster foot is secured to the top plate without using the centre rivet or bolt, thus eliminating the usual source of weakness in casters. Each caster is fitted with ball bearings, and has a composition rubber wheel of 2in. diameter.
In the case of the cabinet type stands, the cabinet is fitted below the bottom tray, and may have plain steel or expanded metal walls. All locker type stands are provided with a brass lever lock and key. There are six different models of various sizes in the case of the plain stands, and four in the case of the locker-type stands. Further details, together with prices, may be had on application to the makers at the address given above.
A Universal Filing Machine
A new machine tool which eliminates slow and tiring hand filing and at the same time enables work to be done by unskilled labour in a fraction of the time hitherto required, has recently been developed by Lorant and Co., Ltd., of 98-100, Croydon Road, London, S.E.20.
With this machine, which is known as the "Rindis" filing machine, all metals, synthetic materials and wood can be roughed out and finished in one operation. This is particularly important for repetition work. The machine works with a rotating double-sided circular file—milling file— manufactured from a high-grade alloy by a special method. It is hardened, and has undercut teeth. The peculiar teeth arrangement produces the best cutting action due to the angle at which the material is brought in contact with the teeth of the disc. The circular file discs are about l0in. in diameter, with rough or smooth teeth arrangement.
Due to the cutting action and teeth arrangement there is no clogging and consequently the output is claimed to be three to four times as much as with grinding. Further advantages are that each side of the filing disc keeps its sharp cutting edge for long periods and when blunt these discs can be repeatedly re-sharpened. Only small power is required (1/2 h.p.), and the working cost is very low. The head of the machine is on a heavy cast-iron base, and the working spindles are made from high tensile steel and run on ball bearings, taking axial and radial pressure. They are also adjustable. Nine speeds are provided for the filing discs.