There is usually fixed above the sucker a short iron valverod, with a device known as a rivet-catcher to prevent damage to the pump by the dropping of rivets from the pump-rods.
At the cal culated position of one of the points of contrary flexure all the rivets of the top boom were cut out, and by lowering the end of the girder over the side span one inch, the joint was opened - -- Section of Newark Dyke Bridge.
Then the rivets were cut out similarly at the other point of contrary flexure and the joint opened.
Soft steel is used for rivets always, and sometimes for the whole superstructure of a bridge, but medium steel more generally for the plates, angle bars, &c., the weight of the bridge being then reduced by about 7% for a given factor of safety.
The shearing area of rivets in tension members was made r z times the useful section of plate in tension.
For compression members the shearing area of rivets in butt-joints was made half the useful section of plate in compression.
This explains the failure of boats built of commercially pure aluminium which have been put together with iron or copper rivets, and the decay of other boats built of a light alloy, in which the alloying metal (copper) has been injudiciously chosen.
The distortion which rails undergo in manufacture and use is incomparably less than that to which rivets are subjected, and thus rail steel may safely be much richer in carbon and hence in cementite, and therefore much stronger and harder, so as to better endure the load and the abrasion of the passing wheels.
Thus the typical carbon-content may be taken as about o 05% for rivets and tubes, 0.20% for boiler plates, and 0.50 to 0.75% for rails, implying the presence of o 75% of cementite in the first two, 3% in the third and 7.5% to 11.25% in the last.
Nails, rivets, chains, fire-irons, locks and safes are produced.
In miscellaneous metal trades, embracing tinplate goods, wire workers, makers of stoves, grates, ranges and fire-arms, makers of bolts, nuts, rivets, screws and staples, and those occupied in several subsidiary trades, the number of operatives in 1901 amounted to 13,209.
Even the simple elements of rivets and bolts have produced immense developments since the days when bolts were made by hand, holes cored or hand-drilled, and rivets formed and closed by hand labour.
Those pieces are connected at theii joints or surfaces of mutual contact, either by simple pressure and friction (as in masonry with moist mortar or without mortar), by pressure and adhesion (as in masonry with cement or with hardened mortar, and timber with glue), or by the resistance of fastenings of different kinds, whether made by means of the form of the joint (as dovetails, notches, mortices and tenons) or by separate fastening pieces (as trenails, pins, spikes, nails, holdfasts, screws, bolts, rivets, hoops, straps and sockets.
All portions of the frame are united by hot rivets of mild steel or wrought iron, care being taken that the sum of the sectional areas of rivets affords in each case a sufficient amount of metal for the safe transfer of the stresses.
Rivets are either of wrought iron or of extra soft steel, with an ultimate tensile strength of 55,000 lb per sq.