The chairs on the British system weigh about 45 or 50 lb each on important lines, though they may be less where the traffic is light, and are fixed to the sleepers each by two, three or four fastenings, either screw spikes, or round drift bolts entered in holes previously bored, or fang bolts or wooden trenails.
The total cost per mile of such a line, including all bolts, nuts, fish-plates and fastenings, ready for laying,, delivered in the United Kingdom, is under Soo a mile.
Care should be taken that the ties or fastenings do not eventually cut into the bark as the branches swell with increased age.
The length of the chains (from rock-fastenings) is 1715 ft., and between the piers 590 ft.; the length of the roadway between the piers is 550 ft.
Over the anga is sometimes worn an overcoat called a choga; this is made of any material, thick or thin, plain or ornamented; it has one or two fastenings only, loops below the breast whence it hangs loosely to below the knees.
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.
If the joint be provided either with projections and recesses, such as murtises and tenons, or with fastenings, such as pins or bolts, so as to resist displacement by sliding, the question of the utmost amount of the tangential resistance CQ which it is capable of exerting depends on the strength of such projections, recesses, or fastenings; and belongs to the subject of strength, and not to that of stability.
Driving pulleys are usually constructed of cast iron, and are of circular form, having a central nave by which they are secured to the shaft by keys or other fastenings, and straight or curved arms connecting the nave to the rim, which latter is of a form adapted to the connector.