Paper-Cutting Machines Part 1

Paper-Cutting Machines.

by Niel, Jr., Gray.

PREFACE

The paper-cutting machine is a recent development in the industrial world. Its importance in the graphic arts is only just being recognized. That it has heretofore been considered an apparatus of minor importance is proven by the lack of information on the subject, either historical or technical. No mention is made of a paper-cutting machine in the eleventh edition of the Encyclopaedia Britannica, either in the index or under the various trade headings. Mention is omitted entirely from De Vinne's History of Printing. There are no references to it in many other standard books, nor in the engineering libraries; neither are there any comprehensive articles on the subject in any of the trade journals, either American or foreign. A few scattered references may be found in dictionaries and manuals having to do with bookbinding and presswork.

This manual on the paper-cutting machine has the distinction of being, as far as the author knows, the first book ever written on the subject. It will endeavor to help toward a better understanding of this important mechanism, its use and care, and it may also serve as a starting point from which subsequent treatises may be written.

The difficulty of making a successful machine of this kind to meet the new demands for accuracy, speed, convenience, and safety, has been overcome gradually in recent years and there are now several machines quite efficient and adequate to meet these demands of the modern manufacturer. To coordinate a number of inanimate pieces of steel and iron, to operate at high speed with precision, requires fine skill.

The evolution from the first cutting machine--the old hand-operated wooden plough and press--to the present power-driven steel mechanism is like the advance from the old wooden sailing vessel to the modern steel s.h.i.+p.

The objects of this manual are to acquaint the beginner with the essential features of the machine itself and to provide clear, comprehensive information which will enable him to become a competent operator. It is not possible within so small a book to give complete detailed instructions for all the different conditions which may arise in the many kinds of work done in establishments where paper-cutting machines are used. Each of these places has its own particular requirements; and while the machine can do its part quickly and efficiently it needs the intelligent and skillful operator to get good results. The instructions given herein for a few cases, which have been made as general as possible, indicate the complexity of this operation as carried on in modern workshops. There is necessity for a careful study of the subject in any important industry to insure this part of the work being successful and profitable.

Not all the kinds of cutting machines in use in the printing and bindery industries are considered in the following pages, but simply the typical machines in common use for cutting and tr.i.m.m.i.n.g printed paper. There are many other styles, such as die-cutting presses, automatic book-tr.i.m.m.i.n.g machines, punching, stabbing, and eyeletting machines, rotary cutters and revolving-blade cutters attached to presses and other paper machines. These might properly be cla.s.sed under the t.i.tle, but as they are chiefly specialized machines the limits of s.p.a.ce do not permit a consideration of them here.

PAPER-CUTTING MACHINES

_Importance of the Paper Cutter_

A paper-cutting machine is used for dividing piles of large sized sheets into smaller sized sheets; also for squaring a pile; _i.e._, making all four corners rectangular; and for tr.i.m.m.i.n.g off irregular or incorrect 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 cooperation with every department is necessary to produce good work.

No matter how fine the printing and color work is, if the margins are uneven and the folds mismatched, then the resulting air of slovenliness discredits the entire work. The final touch that gives the character to a piece of printed matter is the way it is trimmed.

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 tr.i.m.m.i.n.g. The earliest cutting machine was no doubt a sharp stone or a stick; then a piece of metal, dragged across the parchment, with a guide to keep the cut in a straight line. The sheet was simply held by the hand, and later the straight-edge formed a clamp also.

About the fifth century the important step of folding the vellum into leaves became the practice. The instrument which we know to-day as scissors or shears probably had a large part to do in these early operations. With the invention of printing and the multiplication of books larger and stronger means were necessary to cut the sheets.

Although the book with the untrimmed sheets was the rule of this earlier time, and of a later time, for the smaller books and for divisions of the sheet a cutter was necessary.

For a time the cutting of piles of paper was done by hand with a knife, a small pile being put upon a table and a weight laid upon it. The operator leaned his weight with one hand upon it, while he cut with the other. The earliest attempt to improve this consisted of a table, a framework of wood or metal above it, having a groove in which the knife could be worked, and a screw clamp to hold the pile. The knife was originally short; then longer, until it became long enough to cut through the thickness of the book. The deckle-edge of the earlier and untrimmed books was improved upon and made easier to turn over and refer to rapidly by the improvement of tr.i.m.m.i.n.g the leaves. The hand-plough cutter was probably the first successful machine intended to cut a number of sheets at a time.

In the Haupt Halle at the great Graphic Arts Exhibition, Leipzig, 1914, were some ill.u.s.trations showing the earliest German cutting machines and their evolution to date. The earliest among them is the lightly constructed hand-driven vertical cutter of 1855. This consisted of two side frames, the knife-bar guides in their slots and a large hand wheel at the right. The next stage was a cutter of 1876, a hand-driven wheel at the right turning gears above and outside the table. A crank and a rod connected to the center top of the knife-bar pulled the knife in the direction of the two slots in the knife-bar, giving it a shearing motion. This model is the same as that used by most German manufacturers for both hand and power-driven cutters until within a few years, when the greatly improved, rapid, and more convenient American examples became known.

From simply pressing with the hand to hold the sheets the hand clamp was evolved; then the clamp was attached to a gear by which it could be held down on the sheets with greater and steadier pressure. To quicken this operation the spring clamp was devised, with automatic pressure--fixed at first, then variable to suit varying requirements.

Perhaps the most signal advance in the art of paper-cutting machinery that has been made is the invention of Samuel R. Brown, who devised the fixed "throw" of the knife by means of two cranks at opposite ends of a shaft parallel with the knife. This control of the knife enables a hair to be cut through, or half through, or the knife edge to just touch it, with remarkable precision. The various other mechanical connections for power-cutting machines between the pulley and the knife, consisting of rolls, slots, guides, cams, chains, levers, etc., all require a great number of parts between the pulley and the knife, with the consequent and necessary "looseness" of the mechanism. This allows, after short wear, a play or "chug" of the knife which quickly tends to destroy its best cutting abilities.

The evolution of the cutting machine has been rapid and distinctly marked in all its essential features, from the oscillating plough to the vertical stroke, to the shear stroke, to the double-shear stroke; from a single-rod pull-down of the knife (by a chain, by a cam, or by a crank) to the two-rod pull-down by cams, rolls, slots, slides, to the cranks which give a fixed dependable stroke; to the cranks which give a fixed dependable stroke, and at the same time pull the knife endwise; from swinging-link shear to a straight-line shear; from man-drive to power-drive; from driving by power fixtures in front and outside the frame to fixtures located back and underneath; from low piles to high piles; from hand clamp to power clamp, to self clamp, to automatic clamp, finally to friction adjustable pressure clamp; from measuring by rule to the use of rapid automatic measuring and s.p.a.cing devices.

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; with a powerful clamping pressure automatic for all height piles and instantly adjustable for heavy or delicate work; with universal fine adjustments for squaring the back gage with the knife; with a simple change for the cutting stick; with the driving shaft running at a low speed; and with a powerful main driving clutch or friction material that will not cut or damage the parts under the heavy, constant thrusts.

_Description of Typical Machines_

PLOUGH AND PRESS CUTTER

An early form of cutting machine, made almost entirely of wood. The pile of paper or book was clamped to the table by the upper cross-bar of the clamp, which was brought down by the geared vertical arm. As shown by picture, these arms were raised and lowered by turning the large toothed wheel. The steel chisel (A) operating in a holder running in a groove, was moved to and fro across the paper, cutting deeper each time as the chisel was gradually lowered by the handle.

[Ill.u.s.tration: Fig. 1. Plough and Press Cutter]

CARD CUTTER OR TRIMMER

Card trimmers are knives hinged at one end to a base upon which the work is laid and held, while the knife is pulled down by hand to shear it off against a metal edge. Stock cut this way has a slight burr on its lower edge, caused by the "drag" or downward pressure of the knife.

[Ill.u.s.tration: Fig. 2 Binder Shears or Table Cutter]

[Ill.u.s.tration: Fig. 3 Card Cutter and Trimmer]

To cut cards free from burr a rotary card-cutting machine is used, with a rotating shaft carrying a small wheel cutter. These cutters are used on a workbench.

[Ill.u.s.tration: Fig. 4. Hand-Lever Cutter]

[Ill.u.s.tration: Fig. 5. Bench-Lever Cutter]

HAND-LEVER CUTTER

Hand-lever cutters stand on the floor and have a convenient height table to lay the work upon. The cut is made by pulling the knife down through the pile. The knife is hung from two swinging links, and is easily operated when it has double shear and a toggle crank connection to the hand-lever shaft.

[Ill.u.s.tration: Fig. 6 POWER CUTTING MACHINE (HAND-CLAMP) Knife Pulled Down at One End]

Power cutting machines subst.i.tute power fixtures for the hand (sometimes in addition to the hand operating fixtures), and eliminate labor and save time. A hand-clamp power cutter is operated first by s.c.r.e.w.i.n.g the clamp by hand down firmly upon the line where the work is to be cut; then pulling the starting lever, which causes the knife to make the cut, return to the top, and stop.