BAIRD &.TATLOCK (LONDON) LTD. 



Fig. I 



Fig. 2. 



3677 



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3677 



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>77 T Machine, devised by Capt. Sankey, for rapidly testing Steel and other Metals, 



intended for technical use . . . . . . . . . . 20 



Owing to the large amount of information gathered during many years, in connection with Ihe tensile tests 

 lich have been used for exhibiting the properties of steel and other materials, such as brass and bronzes, employed 

 mechanical engineers, it is usual to specify that test, and it is relied on in cases of dispute. At the same 

 ne, a tensile test is not deemed reliable if made on specimens smaller than -inch diameter, with, an overall 

 igth about 6 inches, so that a comparatively large piece of steel or other metal, involving considerable expense 

 machining, has to be prepared, and a testing machine of a pulling capacity of not less than 30 tons is necessary. 

 :ch machines are costly, and, moreover, require an expert to work them, and only large works are able to afford 

 is outlay, therefore the small user must have recourse to testing works, involving considerable expense and 

 'lay. The practical result to a great extent is that tensile tests are only made when definitely specified as 

 -rt of the contract, or in case of dispute, and are not used when the user is accepting material that he has 

 rchased. He therefore relies on the statements of the suppliers of the material. There is, consequently, a 

 c l:ld in workshop practice for a simple test which can be rapidly carried out, can be relied upon, and requires 



ly a small amount of material and a test piece of simple form. 



For many years a simple bending test has been in use in workshops, the measure of the quality of the material 

 ing the degree of bending withstood before fracture, the resistance to bending, and the appearance of the 

 icture. Personal experience is required for this test, and results do not lend themselves to be stated in definite 

 ures ; it is, therefore, not possible to use this test as a criterion when buying, or selling. If a machine, however, 

 > ;re so constructed as to record automatically the degree of bending, as well as the resistance to bending, the 

 rsonal element would be removed, and such a machine could be used for the above purpose. 



The machine described fulfils these conditions, and it provides a simple and inexpensive, but at the same 

 ne absolutely reliable, shop test of the materials, such as steel, brass and bronze, used by engineers. The 

 st pieces are $-inch diameter and 4 inches long, consequently they are inexpensive to make, and can often be got 

 t of even a finished piece of work without injury to the piece. The test itself takes about one minute, and 

 e result is automatically plotted, by the machine, on a strip of paper. This record shows the number of bends, 

 e bending effort of each bend (measured in pound-feet) .and the total energy (in foot-pounds) required to break 



:e test piece. This record can be examined at leisure by a competent person, but the actual test can be per- 

 rmed by an intelligent labourer. It is to be noted that the appearance of the fracture obtained helps considerably 



: determining the value of the material ; some little experience, however, is needed before a true judgment can 

 ' formed, and it is difficult to give a description of these fractures that will really convey a true idea of their 

 ; pearance. The best plan is to retain examples of the fractures of suitable and unsuitable steels, etc., for the 

 ; rpose of compaiison. 



Fig. i is the machine ; Fig. 2 shows an unbroken and a broken test piece ; and Figs. 3, 4 and 5 are reduced 

 csimiles of some records. 



A Pamphlet giving full particulars of the machine, and of the results obtained with it, will be sent on application. 



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