Jr. Niel Gray

“ The knife that fulfils the specifications given elsewhere furnishes the second. And third, the man whose standard of work is high, who is conscientious in following his instructions, who is big enough and broad enough to understand how important his position is, and how necessary, therefore, it is for him to coöperate with every other department in a friendly and intelligent manner, completes the tripod that can stand up successfully under any job.
A cutting machine is a sharp-edged tool and, therefore, dangerous when run by a careless or unskilled operator. ”

“ The character of the cutting depends upon, first, the machine, second, the knife, and third, the man.
Successful cutting is a fine manual art. The finest razor improperly stropped and used in unskilled hands does poor work. The finest cutting machine unintelligently operated will stultify the best efforts of the printing plant.
The machine that has the simplest mechanism evolved by long experience and study ensures the first safeguard of accuracy. ”

“ A general rule for the length of bevel on knives is two and one-half times the thickness of the knife. This may be varied to suit the different materials to be cut, but must be held within reasonable limits to preserve the strength of the cutting edge of the knife and also to secure accurate, clean cutting.
The face of a knife should be as nearly flat as possible and must not be convex. It is better to have it concave than convex, but not over two or three thousandths of an inch concave. A knife that is too concave or convex will tend to dig in or out of the work. ”

“ Be particular to see that the driving pulley on your machine runs at the speed given for it on the manufacturer's directions.
Keep the machine always in adjustment. See that the brake band is adjusted so that when the starting lever is thrown in to start, the friction is entirely released and there is no drag on machine.
Do not allow the knife to sink any deeper into the cutting stick than to sever the last sheet of the pile.
Never use more pressure on the clamp than is necessary to hold the pile without drawing or slipping; any additional pressure is only an added strain on the machine. ”

“ The double-shear cuts more like a pair of scissors, the knife edge entering each sheet at its side and gradually cutting across it. Its advantages are less power required to cut, less strain on the machine and the knife, a more perfectly cut edge and a smoother face to the pile. ”

“ Some printers and binders sort and bale their waste and dispose of it so as to make a considerable saving, but few understand how a little care and system can be made to return a good profit.
There is another waste, sometimes far greater in amount, caused by the careless cutting of stock. A thoughtless operator will often try to save ten minutes by hasty calculation and then waste stock through inaccurate cutting that costs several dollars. ”

“ It is not generally understood what a large amount of power is required to drive a paper-cutting machine, and how important it is that the number of working parts connecting the belt pulley to the knife be as simple and few as possible in order to eliminate friction and lost motion, and to secure efficiency. Every cut costs money for the power consumed. ”

“ Where there is much cutting to be done and the machine is in constant use, it is well to keep extra knives on hand to allow one to be sharpened while the other is being used.
A specially tempered knife is best for boards or varnished paper. Gummed and varnished stock are likely to break small pieces off the knife edge. The double shear motion for the knife now furnished on the new automatic rapid production cutting machines practically eliminates this trouble.
The first place to look when work is not cut true, after making sure there is correct clamping pressure, is the knife. ”

“ A pile may be tested for squareness by jogging it in the cutter table against both the back gage and the side gage, if the machine gages are themselves in perfect adjustment. If it is difficult to see whether the sides of the pile are close against the gages at all points, narrow strips of paper put between the pile and gages will show whether the pile touches the gages uniformly. ”

“ An inch-high pile of writing paper with a sharp knife may take one thousand pounds for each foot of length of the knife to drive it through. A higher pile on a fifty-inch power cutter may take three tons pressure, plus the automatic clamping effort and plus frictional losses, and (more important) plus a tremendous increase in case the knife is dull.
Care of the Machine
A man is known by the condition of the machine he keeps. Keep the knife sharp. That is the first rule to repeat every day and every hour of the day. The second rule is to oil every hole and place required on the machine. ”

“ A primary difficulty in cutting-machine work is due to the great variety of papers and sizes required to be handled on the machine. This varies from little narrow slips to piles the full width of the table, from a few sheets to a pile the full height allowed by the clamp, and from soft book paper to stock nearly as tough as tin. All these varying conditions cannot be met with equal success in one automatic machine. Therefore, superior intelligence rather than unusual muscle should be required of the operator. ”

“ To trim books on a cutting machine, take as many as will make a pile about three inches high, and jog at the head and back. Set the back gage the exact size to which the book is to be trimmed; put the books in the machine with the head against the side and the back against the back gage. Run down the clamp, provided the machine has a hand clamp; an automatic or self-clamp requires nothing more than to pull the lever. When the cut has been made and the machine stops, remove the books and put to one side. ”

“ The time and labor required to cut a job depends upon the number and kind of motions of the hands and body and feet that are made to get the stock ready and to take it away. The fewer motions necessary to do this and to operate the machine, the easier and pleasanter it is to work at a cutting machine. ”

“ Board fillers are always laid on top and the book placed so that the knife will cut against the back.
Brochures with extended cover should have the stock first cut to size of cover before printing, and sufficient extra stock allowed for an all-round trim of the inset after, especially at the fore-edge where after folding in sections the inner sheets are apt to bulge forward. The printer should know how much will be taken off in the after trim to enable him to allow uniform widths of margin. After a job is bound, the cutting machine cannot remedy any defect of edges. ”

“ It increases the possible printing output largely because presses of large size can now print many duplicates of a single design on a single sheet, and many of these sheets piled can be separated at a single cut, whereas a fly or rotating cutter cuts but one sheet at a time.
The importance of the paper-cutting machine can hardly be overestimated. The correct position of the printed matter, the widths of head, tail, and fore edge may be destroyed by careless cutting. Friendly coöperation with every department is necessary to produce good work. ”

“ A few drops of oil on the palm of the hand and applied to the four front and back faces of the knife-bar prevents dripping on the table from the oil can. Run the machine through a few strokes after oiling and then wipe off clean with a cloth or piece of waste the surfaces against which the stock to be cut is placed.
When oiling, remember it is only the oil that reaches the bearing that does any good. Any surplus that runs over and defaces the machine is waste. ”

“ Cuttings and waste may be disposed of by throwing them into a large bag attached to or placed near the machine. When filled, this can be taken away and another substituted. Throwing waste on the floor should not be tolerated. It is untidy, costs time and labor to gather up, and is dangerous.
A light box on wheels is also a good plan for caring for waste of this kind. In some places where there is a great deal of trimming, a chute in the floor next to the machine provides a convenient method of disposing of waste from a number of machines. ”

“ Accidents occur through failure of the operator to watch his own motions and because of the improper operation of the machine through failure of some of its parts. Sufficient safety devices to make all accidents impossible would render the cutting machine as useless as an axe in a velvet case. Accidents which occur from undue wear or neglect to oil are apt to happen. ”

“ The back gage is moved and controlled on the machine table in several ways. In the simpler machines the gage is attached to a rod under the table, a long slot in the center of the table allowing the connection of the gage with the rod below. The rod is attached to the gage with a worm gear and is operated by a small hand wheel at the front of the table. In other machines the gage is attached to a steel cable, or a metal tape, or a chain which passes over wheels at the back and front below the table. ”

“ Single-Shear Stroke—The stroke of a knife which has a side-wise motion at the same time that it descends, with its edge always parallel with the table top. The single-shear cuts the entire width of each sheet at the same time all through the pile.
Solid Knocker for Throw-Out—This is a part solidly fastened to the shaft (or gear) making one revolution for each cut of the knife and that throws the clutch out positively and puts on the brake throwing in the safety bolt after every stroke of the knife. ”

“ The best paper-cutting machine is designed with a knife motion operated by cranks which give an endwise pull to the knife; with the table of medium height; with quick and accurate adjustments for the knife; with a foot treadle for bringing the clamp down to the pile when desired to see exactly where the knife will strike; with an accurate and dependable device for moving the back gage and the pile and measuring quickly the widths to be cut; with starting handles easily reachable without bending ”

“ Knife-Bar Motion—A mechanical way of imitating the action of a draw shave in pulling down the knife. The nearer it is to the hand method, the more simple and successful it is. Rods connected to each end of the knife-bar and pulled down by simple cranks at each end approach nearest to the method of human hands.
Lift—The pile of paper or other stock cut and handled at one time.
Marker—A part of the clamp on some machines, separate from the pressing part, that may be pulled down by a treadle to show where the knife is going to cut. ”

“ Modern power automatic-clamp cutting machines, in spite of the high speed of their operation, are able to cut with absolute accuracy. Perhaps on no other machine will a little careful study return so large a profit in dollars and cents.
Evolution of the Paper-Cutting Machine
The practice of cutting paper began long before the making of the book of bound leaves, and the necessity of making a number of sheets of the same size called for some mechanical means of cutting and trimming. The earliest cutting machine was no doubt a sharp stone or a stick ”

“ A sharp knife and rubber bands are all that are necessary.
Trimming Books
A common error made by printers is to make up forms nearly the full measurement of the leaf, thereby leaving the binder very little trim margin. A standing rule of every printing and binding establishment should be to allow one-eighth of an inch trim margin for the fore-edge, head, and tail of all stitched tablets and quarter-bound cut-flush books. All sewed books should have three-sixteenths of an inch for the fore-edge, and one-eighth of an inch for the head and tail trim margins. ”

“ The ratio of the power applied in hand clamping to the pressure secured on the clamp is, in ordinary commercial machines, about 1 to 150 for small machines up to 32 inches wide, using a 2-foot-diameter clamp wheel and overhead screw. The ratio of power in cutting machines 34 inches and wider, having a 11⁄2-foot-diameter clamp wheel, and worm of 3⁄4-inch pitch at the side engaging a worm gear keyed to the clamp shaft, is about 1 to 180. That is, a pull by the hand of 1 pound on the overhead clamp wheel will produce about 150 pounds pressure of the clamp on the stock to be cut ”

“ Hone the knife only on the bevel. To remove the wire edge burrs along the edge lay the hone flat on the face and rub gently so as not to round over the edge.
A knife will sometimes cut better after it has been ground the first time. A polished knife will give a better surface to the cut. The cutting of the same kind of stock will often vary with different makes of knives. An oily rag tied to a stick kept handy and passed along the bevel of the knife before cutting hard stock will improve the cut. A blunt bevel is preferred for hard stock; a long, thin bevel for soft stock. ”

“ Special spacing devices for the back gage are revolutionizing many branches of work. The usual screw or cable is relatively slow and undependable and requires care and time to move the work the exact distance required.
The new way is to equip the cutting machine with a back gage operating mechanism having stops which can be set for any width to be cut. The operator simply pulls a lever between the stops, which instantly moves the pile and measures it exactly. Production has been increased six hundred per cent. ”

“ There is unavoidable waste, of course, but there is often a great deal of unnecessary trimming. When the necessary trimming runs up into hundreds and thousands of pounds, as it does in all large plants, it is worthy of notice, especially when it is realized that this waste has been paid for at the same rate per pound as the stock that is actually used. ”

“ Deterioration takes place in a paper-cutting machine chiefly in the knife, friction clutch, driving-shaft bearings, knife-bar guide ways, and knife pull-down connection. Depreciation in the entire machine occurs rapidly when it is not kept oiled, adjusted, and clean. ”

“ Brake, Automatic Friction—Generally a band with a lining which grips automatically the outside of a wheel fastened to the driving gear and stops it promptly after every cut when the knife rises to the top.
Chug—The action of the knife that results from lost motion in the parts connecting the knife-bar to the parts that operate it. "Chug" is caused, first, by the looseness of fitting necessary to permit the parts to operate without heating, and second, by wear of these parts. "Chug" dulls knives and spoils stock and makes expense for grinding, sharpening, and knife replacement. ”

“ With the modern high-speed machine operating at from twenty-five to forty cuts a minute, the time consumed in the cutting room is not the time taken by the knife to pass through the stock, but rather the time getting the stock laid up and measured ready to cut. ”

“ A well designed and built paper-cutting machine will last with care nearly half a century. The prudent manager, however, will find he is obliged to discard most of the machines of various kinds in his plant in much less than twenty years in order to keep pace with the newer shops starting with the advantage of later-designed machines. ”

“ Keep your hands and apron clean. Keep the machine clean in every part.
Use only wrenches furnished with the machine, because they fit the bolt heads properly and because they are the correct lengths to put on the proper tension.
Do not use a monkey wrench, because, unless the jaws are carefully adjusted, it will destroy the bolt heads and if used on small bolts, on account of its length and power, is apt to strip the threads or break the bolt or part.
Occasionally go over every part of machine and see that all taper pins, bolts, nuts, etc., are snug in place. ”

“ When cutting lithographed work or similar close-register printing, where large sheets are apt to come with an irregular edge, a small wooden block against the back gage or the side gage at points on the sheet where the original register guides of the press were placed, will usually insure cutting on an accurate line with the printing. ”