SHOOTING IN RIVETS.

Waipa Post, Volume XX, Issue 1179, 8 December 1921, Page 2

SHOOTING IN RIVETS.

REMARKABLE INVENTION. An interesting demonstration was given in London recently of a new apparatus which, may he used under water to mend ship’s plates: by riveting a fresh plate over a hole such as would be caused by a collission or by striking the bottom. The appliance is the invention of Mr Robert Temple, who produced, during the war, a trench howitzer which was noiseless and without recoil. \ A large number of experts interested in shipping and engineering witnessed the demonstrations. Mr Temple explained the essential feature of his device is a new use for explosives. If he is correct in his views the science of ballistics will require revision. The new tool is portable, and can be employed under water, or in other ways for the cold riveting of ship’s plates. It is about the. size, and suggests the shape, of a garden hand-pump, and, with its accessories, it can be carried in a box like a suit case. The tool carries a bullet in the .form of a stud, bolt, or rivet, which is fixed in a head carrying a charge of explosives less in quantity than that of a .303 rifle. It is short and light, and is fixed in a driver or gun. The bullet, of case hardened machine steel, is impelled forward by the detonation of an explosive charge by means of pressure applied to a percussion cap. A high velocity is imparted in a very short distance, and the explosive charge can be varied according to the thickness of steel which is to be penetrated. The point of the stud is shaped for penetration, while the back half is provided with a thread on to which nuts can be screwed when the stud has been imbedded in the plate. In attaching a stud to a plate the tool is held in position over the plate. Upon the application of a little pressure the stud suddenly imbeds itself in the plate. There is no noise, no flash, no gas evolution, and, above all, no recoil. This: has been taken up in an ingenious manner. Penetration is effected without the dragging of the metal such as occurs in punching. Extrusion of the plate occurs at both ends of the penetration, while a taper thread on the situd does not suffer serious deformation during penetration. The metal thus appears to open and close again firmly on the penetrative rivet, which becomes very firmly fixed. Thus ,in one case a half-inch steel stud embedded in a 5-Bin boiler plate required a pressure of over seven tons to dislodge it. Where the method is used as a means of lifting, the weight to be lifted will determine the number of such studs which must be affixed.

In effecting the repair of a hole, a plate provided with a. number of suitably disposed holes is lowered and held over the gap. The tool is placed over a hole, a small guide being provided to ensure that the diver gets the spot. A bullet is now shot, firmly fixing itself in the boiler plate to wards which the repair plate is pulled by nuts upon the threaded ends of the studs or rivets.

Mr Temple said he had no idea of the velocity with which the rivet was driven, but it must be enormous. He advanced the theory that the rivet causes the atoms of the plate at the spot struck to flow, and then they close in on the spot and bind it. Certainly, there is a bulge on both sides of the plate around the rivets. The keenest interest was shown in the invention, and Mr Temple was asked many questions on technical points. His answers suggested some surprising developments. He remarked, amid cordial approval, that explosives had done enough destruction under man’s control, and he'aimed at turning them to the work of recontruction.