Historical Article

From the 1897 British Print­er by Mr James Trotter

Heriot Watt (from ECP)
Heri­ot Watt (from ECP)

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.