From the 1897 British Printer by Mr James Trotter
B.P. readers are well aware, there is quite a variety of cylinder machines upon the market, and to describe the construction of all the different makes would occupy more space than would be allowed. At the same time, although there are so many different makes of machines, the real difference is very small, and as a rule it is merely in such details as a swinging cylinder, geared rollers, automatic feed-board, etc., and with a day or two’s experience any machineman used to one make is able to handle another. The mechanical motions, as applied to all machinery, are of two kinds: the motions which change the character of the action, and those which increase or diminish its force. Printers have most to do with the first, for from front to back the printing machine is one continual change of motion, and all who wish to be successful printers must not only know how to put a forme upon the machine, make it ready, and work off, but must obtain a practical acquaintance with the working of the different parts of the machine they may be in charge of. This is generally admitted, and yet how many members of the fraternity trouble about it? they drop the forme upon the bed, get the right pitch — and sometimes the wrong one — lock up, make ready, start the machine, and for the next hour or two are content with watching the colour—or the foreman, but never fora moment try to ascertain the mechanical movements of the different parts which constitute the machine under their care.
The first piece of mechanical power to be dealt with is the lever used for starting the machine. This is one of the simplest levers upon the machine, its work being to shift by means of a fork the belt from the loose to the fast pulley, and vice versa. In this connection it is well to remember that the strain upon a belt diminishes according to the speed it runs at, and the frequent breaking of belts is very often caused by running the machine at too low a speed. Another cause of breakage is the sudden striking on of the belt to the fast pulley, and this may occur should the belt be somewhat slack, the downward portion gripping the pulley while the loose section goes up with a jerk, thus — as might be expected — causing it to snap at its weakest part.
Next may be noticed the gearing necessary upon all machinery where the mechanical power of one part has to be transmitted to another. In this case we have the spur-wheels, which transmit their circular motion to the driving-wheels, and turn shafts upon which are the various cams and eccentrics. The eccentric is an appliance for obtaining the backward and forward motion of a crank, and is simply a circle revolving about a point away from its centre; as a rule it is surrounded by a ring or hoop, to which is attached the lever in a line with the centre of the circle, and as the shaft revolves it is thrown backward and forward. The cam — the action of which is to convert the circular motion of the shaft into a reciprocating motion — is a curved plate, which, by the action of its curved edge, communicates intermittent motion to another part of the machinery, its great advantage being the extreme accuracy with which it works.
Having viewed the mechanical power, let us for a moment view the construction. Take as a model a quad-crown built by Messrs. John Elliott, Son & Co. Upon looking beneath, this machine gives some the impression that various parts are missing, but such is not the case; the machine is built strongly without any elaborate detail, and is so arranged that should anything go wrong beneath it can be easily got at. This machine has two side frames and four cross frames; the cross frames are bolted and pinned to the side frames, so that if a bolt works loose the pin will prevent the stay from shifting when the frames are in position.
Next come the longitudinal stays, which are bolted to the cross stays. Attached to these stays are the racks in which run the rack-wheels. Then the shaft on the left side is placed through the bearings in the longitudinal stays, and carries the left-side driving-wheel, cam for double inking, ductor cam, and cam for automatic feed board. Upon the right-side shaft are the right-side driving-wheel, cams from which work the levers for opening grippers, lifting feed board, pushing back cylinder against the short stop, and upright lever for braking the cylinder. Following the process of construction, next are put in the rack-wheels, the crank, and the driving-wheels attached to them. Having got the necessary gearing in below, we come higher up and fasten on the bowl rails to the cross stays, put on the bowls or runners, and attach them to the levers working from the shaft of the rack-wheels. The main shafting is next put through its bearings, of which there are five; two are cast with the side frames, two with the end stay, and one is bolted to the end stay between the pinions. Besides the pinions, the main shaft carries the fly-wheel and fast and loose pulleys, with the driving-wheels full in. Then the bed of the machine is put upon the runners, the inking slab attached, and impression bearers and side racks screwed on. The heaviest part of the work — that of putting on the cylinder — follows. The cylinder is put on with the bed full in, the loose cog-wheel put in position upon the end of the cylinder shaft; the cylinder brackets and brasses are then put on and bolted to the side frames; these brackets also support the flying drum. Next are fastened on the roller brackets; and making a move to the back, put on ink brackets, ink cylinder and knife; upon the end of ink cylinder the catch and connecting rod are fastened to the cam already mentioned; an appliance for actuating the ink feeder is worked from the same cam. Turning to the other side of the machine, fix on the brake-wheel to the shaft end of the cylinder, put on the brake lever, and attach the brake and lever for pushing the cylinder against the short stop. All that now remains to be done is to put on the feed board brackets, attach the appliance for working the points, and place the feed board in position. This done, the machine is now ready for the putting on of the belt, which will convey to the machine the circular motion of the revolving shaft.
To complete the work, the printer then puts upon the cylinder the necessary sheets and calico corresponding with the depth of beard upon the cylinder, the larger the better, securing a forme of type. Then it is necessary to set the bearers and adjust the cylinder, which, after being properly set, should not again be altered only under very special circumstances. Making-ready may afterwards be undertaken.