Abstract: A method of casting or moulding an article having an internally screw-threaded hole comprises introducing casting or moulding material into a mould cavity around a core pin formed with segments of a screw thread separated by flutes and also around withdrawable flat core members projecting into the mould cavity with their leading ends fitting snugly into the flutes. The segments of screw thread form the male image of segments of the required female thread. When the casting or moulding material has set first the core members are withdrawn from the mould cavity then the core pin is rotated to bring the screw-threaded segments into the positions formerly occupied by the flutes and the pin is withdrawn axially from the mould cavity. Finally the article is removed from the mould cavity.

Abstract: A method of injection moulding or casting comprises forcing a solid bar of the material to be moulded or cast as a plunger into a closed heating chamber having a discharge opening. The heating chamber is maintained at a temperature above the melting or plasticizing temperature of the moulding or casting material so that the leading end of the bar on entering the chamber melts or plasticizes therein and displaces molten or plasticized material from the chamber through the discharge opening. Apparatus comprises a body member formed with a heating chamber and a straight passage leading into the chamber, a plunger formed of the material to be moulded or cast being slidable in the passage. A thermal barrier may divide the passage into two successive portions.

Abstract: A method of casting or moulding an internally screw-threaded article comprises introducing casting or moulding material around two withdrawable flat core members which overlap within a mould cavity. The leading end face of each core member is formed with a male segment of the female screw thread to be formed in the article, the arrangement being that when the core members meet one another the two screw thead segments of the two core members are located to form two diametrally opposite segments of a male image of said female screw thread, withdrawing the core members from the mould cavity when the casting or moulding material has set and removing the cast article from the mould cavity.

Abstract: A hot chamber pressure casting machine of the type having a gooseneck for drawing molten metal from a reservoir and injecting it into at least one die set movably mounted on a back plate. In one aspect of the invention, a track is provided on the back plate along which closure means for the die is adjustable. In another aspect of the invention, the back plate is in or near a vertical plane and the gooseneck nozzle has a passage, a major part of which lies in or near a horizontal plane when the nozzle is engaged with the die, and the end portion of the passage is inclined upwardly from the major part to the end.

Abstract: A gas nozzle for a gas-using appliance containing a passage for gas formed at least in part in two members which are relatively rotatable while remaining in contact with one another over a surface of contact presented by each member. The passage in each member has a debouchment at the surface of contact on that member eccentric with respect to the axis of relative rotation of the members.