Abstract: To tap a main pipe for connection of a branch pipe thereto, a tubular enclosure is applied to the main so that one end of the enclosure is formed by the main pipe side-wall to be holed. A drill is penetrated through the main pipe side-wall from the interior of the enclosure while being operated from outside the enclosure; the enclosure having its end remote from the main pipe filled by a removable plug which acts as a bearing for the drill-shaft. The enclosure is equipped with a closure member (such as that of a gate valve) which is used as a lock to prevent movement of the plug during drilling. After drilling, the means used to drive the drill are removed and replaced by an extension of the enclosure, the plug is then unlocked so that the plug and the drill retract into the extension under pressure of the main pipe's contents.

Abstract: To ensure that a socket formed on a pipe-end in plastically deformable condition is in no part thinner than the pipe material out of which it is made, the pipe-end is first enlarged in diameter and encased within a contour die formed as envelope for the external shape required of the socket. The enlarged pipe-end is then longitudinally compressed to thicken it and internally formed so as to smooth the internal surface of the pipe-end and impose on it the internal shape and dimensions required of the socket. The required socket shape preferably includes a circumferential groove to house a resilient sealing ring.

Abstract: To ensure that a socket formed on a pipe-end in plastically deformable condition is in no part thinner than the pipe material out of which it is made, the pipe-end is first enlarged in diameter and encased within a contour die formed as envelope for the external shape required of the socket. The enlarged pipe-end is then longitudinally compressed to thicken it and internally formed so as to smooth the internal surface of the pipe-end and impose on it the internal shape and dimensions required of the socket. The required socket shape preferably includes a circumferential groove to house a resilient sealing ring.

Abstract: To provide asbestos-cement and like sheets which are formed by build-up of a thin film on a rotating size roll, with an embossed patterned surface; a flexible mold layer of epoxy resin or like moldable material having counterpart embossments molded thereon, is removably wrapped about and secured to the size roll with its patterned side outward and before commencement of film build-up on the roll.

Abstract: Laminated slabs superficially bonded together are prepared by autoclaving a vertically compressed stack including a plurality of the sheets when initially set but not finally cured and having a polyethylene or like plastic film-like layer sandwiched between each pair of the sheet surfaces to be bonded together. A layer of material other than asbestos-cement may be sandwiched between the asbestos-cement sheets, for example, metal foil, to make the slab moisture-impervious or an array of filaments or wire-mesh material as reinforcement may be used.

Abstract: To provide asbestos-cement and like sheets which are formed by build-up of a thin film on a rotating size roll, with an embossed patterned surface; a flexible mould layer of epoxy resin or like mouldable material having counterpart embossments moulded thereon, is removably wrapped about and secured to the size roll with its patterned side outward and before commencement of film build-up on the roll.