This section is from the book "A Practical Treatise On The Joints Made And Used By Builders", by Wyvill J. Christy. Also available from Amazon: Practical treatise on the joints made and used by builders.
This is effected by knocking off the hardened scale or protuberances on the surfaces of castings, etc, by means of a hammer and cold chisel, called a chipping chisel, having a slightly convex face, and a cutting edge of about 80°. The chipping is followed by filing down, which finishes off the surface to a fair face to obtain a true and equal surface and close joint. The planing machine has to a great extent superseded this method, but it cannot always produce so true a surface as filing and scraping, nor can it be said to be a mightier agent than chipping, for no mass of iron, either wrought or cast, and however hard or tough, can withstand the onslaughts of the chipping chisel. The machine, however, like most others, has its own distinguishing merit of facilitating work and economising labour.
Circular Joint is formed when a convex foot or bearing plate is bedded upon a concave bed plate, or the reverse of this will hold. An iron column under such conditions if not fixed but allowed radial motion is said to lose two-thirds of the strength it would otherwise possess if bedded with a flat bearing. So far, however, as its application to provision for expansion goes in combination with a small allowance for deflection, or springing motion, a circular joint answers excellently well, the lower plate being furnished with a roller bearing, whilst the upper is bolted either to the girder end or rafter foot.
One held fast by clamps consisting of opposite pieces riveted to a plate, etc, in order to seize between them the part to be confined or joined.
This occurs at the angles of wrought iron chain bond and hoop-iron bond when the ends are turned up and down to clip one another. It is also formed by a contrivance called a clip, consisting of an embracing strap or else of a pair of straight, or curved, or bent arms or edges. Bracing-bars are joined to wrought iron piles or columns by means of clips which surround them and project as ears or lugs with an interspace between for the insertion of the bars, the whole being bolted througl, together. The bars are either of angle or T-iron, etc, on else round with flat ends and eyes. When the columns 01 piles are cast the ears or lugs for the cross bracing are cast on them at intervals in the height. The diagonal bracing-bars of submerged piling and overhead columns, which act as ties or struts, must always be made suitable for resisting compression and tension respectively as well as their own proper stresses, though in order to impart the requisite rigidity and stiffness to the bracing the ties should be adjusted to throw the struts into compression. It is on account of the variable and uncertain nature of the possible disrupting forces that provision should be made for the braces to act indifferently as ties or struts as occasion may require. Cast iron sheet piles, ½ in. thick and nearly 2 feet wide, have been successfully secured and jointed by the agency of clips.