Pipe Joint

Pipe Joint is a junction between two pipes without, as a rule, reducing their carrying capacity or fullway, and is usually made by means of a spigot and socket, or with flanges, or a coupling for direct extensions, but with the addition of a T- piece, or bend, or elbow for lateral ones. Flange joints have been already noticed. Cast iron pipes with spigots and sockets fitting loosely are usually run with lead, as described under Run Joint in Section X., and when made to fit tightly, as explained under Turned and Bored Joint. Red and white lead in equal quantities well mixed and caulked with white yarn is used for jointing wrought iron hot-water pipes. Other methods are described under the heads of India-rubber, Iron Cement, and Rust. When the pipes are large, collar joints may be employed, but the shorter the pipe the stronger the main, because the sockets act as bands. Besides the ordinary joint run with molten lead, another kind equally impervious is formed by inserting into the socket a ring of cast lead and driving the spigot end tightly inside it. Painter's patent hydrostatic pipe joint is an ingenious caulk made by squeezing a lead ring between the spigot and socket, which is of peculiar make, by means of the compression of a semifluid passed through a screw-hole in the socket, the force being supplied by a small screw-jack. Marini's pipe joint for steam, etc, consists of an iron collar between two grooved flanges, rings of vulcanised india-rubber being placed in the grooves and the flanges bolted through together. Service pipes when of iron are jointed with sockets screwed on the threaded end of each length with a touch of white lead, unless barrel unions likewise screwed are employed. Cast iron rain-water pipes are connected by inserting the spigot well packed with putty or red lead and tow into the socket, and their junction with the wall is effected with ears, or lugs, or clips and pipe nails. Before building into masonry, the soundness of the pipes should be tested by hydraulic pressure with a force pump. Pivot or Pivoted Joint is a variety of hinge joint formed by a conical or cylindrical pin fixed to the posts of gates, or centres of rails, or centres or extremities of the hanging stiles of doors, etc, to enable them to swing freely. Dock gates furnish illustrations of its use, the heel posts of which sometimes work on steel pivots 12 in. in diameter let into post stones, the sills being supported by-rollers working on cast iron roller paths or runners. A variety of swing bridge derives its name of pivot bridge from its moving on a vertical pivot situated midway between its two ends. Pivot lights are those supported at the sides by centre pins, otherwise pivots and centres.

Planed Joint

Planed Joint is made by means of a machine tool called the planing machine, which to a great extent has superseded chipping and filing in producing, amongst other advantages, well-fitting, smooth, and true bearing surfaces, though planing does not eclipse chipping in producing evenness of surface. Through the instrumentality of planing, all the joints of ironwork, wrought or Cast, can be finished off with parallel faces and a Consequent precise and accurate fit and bearing, which has done much to extend the application of iron to Structures and to inspire confidence in its resisting powers. The top and bottom surfaces of massive cast iron bed plates, the comparatively light ends of intermediate struts set between the segments of upper booms, and the butts and edges of plate iron from ⅛ in. to 1 in. in thickness, are all well and smoothly surfaced by this ingenious process.