The Purchase Department.
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Where to Buy your Supplies.
Interesting and New Supplies from Factory and Showroom.
You Can Get It At--.
" B.W." (Birmingham): With regard to your costs system, you cannot do better than get in touch with the Stolzenberg Patent File Co., Ltd., Bishopsgate, E.C. This company will be pleased to examine your present system and advise as to the suggested nnprovemen Ls.
"Hallite" Motor Jointing.
Messrs. Hall and Hall, of 47, Leadenhall Street, E.C., make a special feature of their standard " Hallite " motor jointing, guaranteeing that every square inch of the material will be found of standard thickness. Sheets, discs and washers are also manufactured, and a great feature is made of the fulfilling of orders by return of post.
Daimler Gear Experiments.
The Daimler Co., Ltd., has issued a booklet dealing with silent transmission. In our issue of 21st November we gave a short account of the experiments and conclusions arrived at, following a series of exhaustive tests, recently carried out by this company. A special department has now been organized for the production of worm gearing, and this is claimed by the Daimler Co., Ltd., to be the finest installation of its kind in the world. It is stated that gearing having a total transmission output of 1,000,000 h.p. per annum can be manufactured at this plant. Mr. F. W. Lanchester, the inventor of the worm gear which bears his name, is responsible for this new department. The booklet deals in concise manner with worm gearing, and treats of the lubrication, efficiency, life, overland capacity, and so on. These notes are illustrated by line drawings and suitable graphs which have been selected from a large number that were made during the course of the experiments. Phosforum Bearing Metal.
Our readers are not unacquainted with the special bearing metal made by Messrs. H. Watson and Sons, High Bridge Works, Walker Gate, Newcastle-onTyne, known as Phosforum. Some short time ago this firm made a special examination of the many metals now used for bearings, liners, brasses, etc., and some interesting microphotographs were taken during the investigation.
We reproduce four selected prints below. It is fairly well known that sand-cast phosphor bronze bearings are often a source of trouble owing to the segregation of the alloy. This leads to the hardening of the bearing metal in places, with resultant tearing of the shaft. The difference between Phosforum and ordinary metal is well defined in the illustrations given below. Fig. 1 shows a sample of this metal magnified 50 diameters, while Fig. 2 represents a specimen of ordinary metal magnified to a similar extent. No. 3 is a further sample of Phosforum magnified 50 times, while No. 4 is of the same metal as No. 2 enlarged to 330 diameters.
The triple eutectic, it will be seen, is evenly distributed in Figs. 1 and 3, being in both eases about 50 per cent. of the area. Tensile tests have shown these metals to be capable of resisting a force of 21 tons ner inch.
The other reproductions show a structure of entirely different quality. In this case the soft matrix predominates. The triple eutectic, or hard portion, is considerably less in area, and it is also irregularly distributed. This means that any weight would be supported on the few hard points, a state of things which would quickly lead to friction and wear. The metal shown in the first and third sections will naturally possess a low co-efficient of friction, due to the large area of wear resisting surface presented.