988 REPORT— 1898. 



design ; and in January- of this year a machine, which is known as a hydro- 

 compressor, was completed and was found to work successfully. 



In making cycle frames it was found that every joint in a frame (usually about 

 ten in number) could easily be made in seven or eight minutes — this time included 

 the assembling of all the tubes, lugs, &c., which constitute a cycle frame, in the 

 machine and the taking out of the completed frame— alter the operation of apply- 

 ing the water pressure. The hydraulic pressures applied to the forming of the 

 joints varied from three to nine tons per square inch. All the joints in a cycle 

 frame are made at the same moment, and, as no heat is employed, the frame when 

 removed from the jig or mould is perfectly true and requires no setting. All the 

 laborious cleaning otf, sand-blasting, and the consequent weakening of the tubes 

 by filing of the metal are entirely avoided, so also is the loss of strength in the tubes 

 due to the tempering of the metal. 



In the brazing process the tubes are first connected to the iron sockets or lugs, 

 which form the connecting pieces at all the angles of the frame, bv means of small 

 screws inserted at the sides of the lugs. The frame is then placed on a hearth of 

 Ted-hot coke, is heated to a bright- red heat by the application of a ' Buusen ' gas 

 jet, and the brass solder is run into all the joints in turn, a suitable flux being 

 employed to efiect the union of the metals. When the irame has passed tlirough 

 this ordeal the brazing material has spread over the external surface of the tubes 

 and lugs, and has to be subjected ta various ' cleaning-oil ' processes — viz., sand- 

 blasting, filing, &c. The former is verj' injurious to the liealth of the woi'kmen, 

 and the latter is necessarily very weakening to the tubes. The frame is also very 

 much twisted by the heat, and the steel tubes themselves are much weakened, 

 especially at that part where most strength is needed — i.e., at their junction with 

 the lugs, this portion being practically brought to the condition of cast metal, 

 and the mechanical hardness due to drawing the tubes is entirely lost. The 

 scale, too, which is so difficult to clean ofi', it must be remembered, is formed by 

 oxidisation, at the expense of the tube. 



With the hydraulic process the time occupied in making a frame is entirely 

 dependent upon the rapidity with which frames can be placed in and witlidrawn 

 from the jig. This device, it must be explained, is a heavy cast-iron mould in 

 two parts, in which the tubes of the cycle frame and the lugs are placed. After 

 these parts are closed, water, under a pressure of from five to seven tons per square 

 inch, is applied to the interior of the cycle frame, and by tliis means the tubes, 

 where they lie within the lugs, are so expanded as to become indissolubly united to 

 them. The interior surface of the lugs is spirally grooved in reverse directions, 

 so that the tubes when expanded are locked therein, and cannot be moved in the 

 direction of their axes or be unscrewed. The closing of the mould or jig which, 

 contains the frame is effected by the action of the piston of a steam cylinder, which, 

 through the medium of a system of toggle joints, exercises the necessary pressure; 

 the mould is then automatically locked. A second stroke of the piston actuates 

 the plunger of a hydraulic intensifier which gives the pressure required for 

 making all the joints instantaneously. The press is then opened, and the cycle 

 frame, completely jointed, perfectly true to shape, and without twist or weakness 

 of any kind, is removed. 



Drawings and samples of the work performed by this machine were exhibited. 



5. Description of an Instrument for Measuring small Torsional Strains 



By E. G. CoKER. 



SATURDAY, SEPTEMBEIi 10. 

 The Section did not meet. 



