Home mechanics for amateurs

Preface

SPECIAL INTEREST ahvays attaches to a posthumous work. It is not always, however, that a work of this character possesses equal merit with one entirel}^ completed before the death of the author. As a rule such works have not had the advantage of the final perusal and correction by the author. Such has not, however, been the case in the present instance, for the following work by the late George M. Hopkins, was completed before his death. Tl ere is no doubt, however, that this volume will come as a surprise to thousands Avho have closely followed Mr. Hopkins' Avork, and who have enjoyed making the many experiments described by him. The present volume contains much matter which has never before appeared in print, and some articles Avhich have already been published in the Scientific American. The object of the work is to furnish food for thought to the amateur, and to give him suggestions Avhereby he may pass many pleasant hours in his Avork-shop. 3Ir. Hopkins Avas an expert mechanic. One of his chief pleasures Avas to make experiments at his home in his Avellequipped Avork-shop and laboratory, and the Avork described in the present volume is nearly all the result of experiments made by him during such ^Mdle" hours. It has been the intent of the author to make the present

PEEFACE.

work as suggestive as possible. No complicated apparatus is required iu carrying out the experiuieuts described. Any one with ordinary mechanical ingenuity and having a lathe and a few tools can make most of the experiments described in these pages.

A few articles by other authors have been included as they are germane to the scope of the book. It is hoped that ''Home ^Mechanics for Amateurs" will prove helpful to as. many thousands as has ''Experimental Science."

PART I. Wood- WoR K I n g

An Inexpensive Turning Lathe. Turning. Wood-Working on a Lathe. Work Bench and Tools for Woodwork. Whittling. Different Shapes of Saw Teeth and the Way they Cut. A Wrinkle in Sawing. Wood Carving 1

PART n.

How TO Make Household Orxamexts

Home-made Grilles and Gratings. Wall Ornaments. Pseudo- Ceramics. Imitation of Majolica. Stained Glass and Objects of Wire Cloth. Japanese Portiere or Curtain. Repousse. An Easy Method of Producing Bas-reliefs. Ornamental Iron Work for Amateurs. Some Things in Wire. Some Things in Burnished Brass. Forming Plaster Objects 31

PART III. Metal-Workixg

Sawing Metals. Soldering. Grinding and Polishing. Silver Work. Metal Foot Lathe. Drills and Drilling. Centering and Steadying. Chucking. Metal Turning. Chasing and Knurling. Rotary Cutters. Easily made Slide Rest. Index Plates for Gear Cutting. Gear Cutting Apparatus. Hints on Model Making. Metal Spinning 89

Telescopes and Microscopes

How to make a Telescope. The Microscope 207

PART VII. Electricity

Practical Primary Battery. Electric Lighting for Amateurs. The Electric Chime. Home-made Electric Night Lamp. An Electrical Cabinet. Simple Electric Motor. Small Electric Motor for Amateurs. How to make a Sewing Machine Motor without Castings. A Design for an Electric Launch Motor. How to make an Edison Dynamo and Motor. The Utilization of 110 Volt Electric Circuits for Small Furnace Work. Recording Telegraph for Amateurs. How to make a Telephone 227

Part I. Wood-workiistg

AN INEXPENSIVE TURNING LATHE

THE BOY who has a turning lathe can readily make many things which he might not feel disposed to buy ; for example, he can make tops, ninepins, and ornamental and useful objects without much trouble and with very little expense. The ancient lathe consisted of two conical points, supported in position by suitable standards, and the work to be done was whirled on these points b}^ means of a strong cord wrapi)ed once around the stick to be turned, with the upper end attached to a spring pole and the lower end secured to a treadle. The lathe we are about to describe is one remove from this primitive lathe of the olden time. It has the two standards with points or dead centers, as thej would be called by machinists, but one of the points projects far enough from the standard to receive a hard wood pulley, having inserted in its side, at diametrically opposite points, two spurs, which enter the end of the piece of wood to be turned, so that when the pulley is revolved by a belt, the wood will be turned on the centers.

This lathe is made almost entirely from strips of hard Avood, 1 inch thick and 2^ inches wide. These strips can be easily furnished by any carpenter, cabinet maker or wagon maker, and an old table may be used for the frame.

The bed-piece is made of two such strips, 2 feet long, and a block of the same material, 1 inch square and 2

[IJ

2 HOME MECIIAXICS FOR AMATEURS

inches long, at one end is placed between the strips and held in place bv wood screws. A piece of thick j)aper is placed between the block and one of the strips,

Fig. 1. An Easily Constructed Wood Lathe.

to make the space between the strips a little wider than the thickness of the block.

To each end of the bed is secured a foot, consisting of a piece of the same strip, 6 inches long. These are secured by wood screws passing upward through holes

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in the lower edoe of the foot, the holes being deeply countersunk to let in the heads of the screws.

The head stock and tail stock are nearly alike, in so far as the wood work is concerned. Each is formed of three pieces of the strip from Avhich the bed is made. To opposite sides of a central piece, 74 inches long, are secured side pieces 4 inches long, by means of screws. These side pieces must of course be square on the end so that they will set squarely on the bed when the projecting end of the central piece is inserted

Fig. 2. Work in the Lathe.

in the slot of the bed. The loAver end of the center piece is mortised to receive a Avooden key or wedge, which clamps the tail stock to the bed. In the tail stock. -J inch from the top, is bored a hole in which is inserted a large wood screw, the point of which is filed conically, as shown. In the head stock is also bored a hole corresponding with that of the tail stock, to receiA^e a large wood scrcAv, i or 5-16 inch in diameter. The head of this screw is cut off, and the head (^nd is filed off conically. This point should project about an inch from the head stock, and to the plain, smooth projeeting part of the screw is fitted a small grooved pulley about 1^ inches in diameter at the bottom of the groove. The pulley should be of Babbitt metal or type metal. In the side of the pulley, about J inch from the hole, are inserted two small screws, about f inch long, which are allowed to project ; these screws are filed to form chisel-edged spurs for driving the work in the lathe. The points should project as far as the point of the conical end of the large screw.

The lower end of the head stock — which is about 2^ inches long — is inserted between the strips forming the bed, and fastened with screws; a piece of paper being inserted to increase the space between the strips, so that the tail stock can be moved easily.

The wood to be turned has a small hole^ — say, ^ inch — bored in the center at each end, and is placed between the centers; the tail stock having been clamped in the proper position, the tail screw is turned with a screw driver until it is forced a short distance into the end of the stick. Then the stick is driven forward on to the center, and spurs of the head stock, and the screw in the tail stock is turned so as to hold the stick, but not enough to create friction. A drop of oil should be put on each center, and the pulley should be oiled.

The rest on which the gouge or chisel is placed while the turning is being done consists of a piece of the wooden strip with a slot in it to allow a 5-inch carriage bolt to pass through. This bolt extends through the slot of the bed, and through a block or washer below. A wing nut is placed on the bolt so that the rest may be clamped in any desired iDosition. To the end of the slotted piece is secured a short piece of the wooden

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strip by two screws passing through the slotted piece and into the wood. The wooden rest should be beveled as shown.

Jt must be frankly admitted this lathe is not an elegant machine to look at, but it is capable of turning out quite reputable small work.

Having made the lathe, it will be necessary to provide some means to drive it. In almost every city and town may be found old sewing machine tables, which have been taken in trade as old iron. One of these can be bought cheaply, and when the treadle is turned around and a round leather belt applied to the lathe pulley and the sewing machine wheel, the arrangement is complete.

Some one may be found good enough to loan a sewing table for the purpose. In this case, an assistant will be obliged to work the treadle while the turning is being done.

As the flywheel should be heavy, not less than 20 pounds, and as it should be about 20 inches in diameter to secure the desired speed, it is perhaps better to fit up the lathe with a wheel and table better adapted to it than a sewing machine wheel and table would be.

The lathe shown in the illustration is mounted on a common kitchen table of the smallest size. In this case, an old wheel is selected at the junk shop; one with a groove in the edge is to be preferred, but a flat rim will answer. The one here shown has a flat face and is provided with a shaft, a crank and standards. The standards are inverted and fastened with screws to the under side of the table top.

A strip of board extending lengthwise of the table is attached to the rear legs with screws, and the piece of board forming the treadle is hinged to it in position to receive the screw Avhich passes through the lower end of the pitman rod or connecting rod, the npper end being apertnred to receiA e the crank pin. A ronnd leather belt is used in this case.

The tools for turning are not very expensive; with two gouges and one or two flat chisels a great variety of work mav be done.

TURNING

There is no secret in turning. It requires a great deal of practice to become an expert, but beyond acquiring the first principles nothing further than practice is required. When reducing a piece of wood to the

Fig. 3. Lathe Turning Tools.

desired approximate size, the gouge is held on the rest with its handle-end inclined downward at an angle of about 60° with the horizontal, the rest being near the work, and the gouge is moved back and forth on the rest, takiiiij; off a slii»lit sliaviug each lime it is moved. The handle is held in the right hand, while the blade of the gouge is held in the left hand, with the thumb pressing on the coneave side. If a plain cylinder is required it may be made by using the flat chisel, laying the beveled edge on the work in such a manner as to produce a drawing cut as the wood passes the edge. If the work is to be cut into at right angles or at any other angle, the chisel is placed on its edge on the rest and held firmly while moving it forward.

In cutting concave forms the gouge is made to make a drawing cut by placing it partly on its edge on the rest. It will be found necessary in either of these cases to hold the tool very firmly on the rest to prevent the edge from drawing itself forward on the wood and spoiling the work. By practice the art of woodturning can be readily acquired even by the use of the ^'Simple Lathe."

For hard wood and ivory a different class of tools is required. The chisels are all flat, not oblique; some of them have edges that are square across; some have V-shaped points and others are round-nosed. For under-cuts and odd work, special tools are bent at different angles. Flat work, such as rosettes, etc., is chucked upon the face plate, or attached with screws to a board fixed to the face plate.

In finishing work the use of fine sandpaper is admissible, but it never should be used to correct poor turning. Wood work, when smoothed a little with fine sandpaper, may be finished by applying to it with a cloth a mixture of shellac varnish and linseed oil, in proportion of about one part of oil to two of shellac. Only a little is applied to the cloth at one time, the polish being well shaken before it is applied. The work in the lathe is rapidly revolved until it is brightly polished and the shellac varnish is hard. If desired, the work may be stained before it is polished. The stains are readily obtainable, and are described in the "Scientific American Cyclopedia of Receipts, Notes and Queries."

WOOD-WORKING ON A LATHE

It is not the intention of the writer to enter largely into the subject of wood-working, but simply to suggest a few handy attachments to the foot lathe which will greatly facilitate the operations of the amateur

Fig. 4. Saw Table wood worker, and will be found very useful by almost any one working in wood. It is not an easy matter to split even thin lumber into strips of uniform width by means of a handsaw, but by using the circular saw attachment, shown in Fig. 4, the operation becomes rapid and easy, and the stuff may be sawed or slit at any desired angle or bevel. The attachment consists of a saw mandrel of the usual form, and a wooden table supported by a right angled piece. A, of round iron

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fitted to tlie toolpost aud clamped by a woodeu cleat, B, which is secured to the under side of the table, split from the aperture to one end, and provided with a thumbscrew for drawing the parts together. By means of this arrangement the table may be inclined to a limited angle in either direction, the slot through which the saw projects being enlarged below to admit of this adjustment.

The back of the table is steadied by a screw which rests upon the back end of the tool rest support, and enters a block attached to the under side of the table. The gauge at the top of the table is used in slitting and for other purposes which will be presently mentioned, and it is adjusted by aid of lines made across the table parallel witli the saw.

Fig. 5.

Saw between beveled Washers.

Moulding Knives.

For the purpose of cross-cutting or cutting on a bevel a thin sliding table is fitted to slide upon the main table, and is provided with a gauge which is capable of being adjusted at any desired angle. For cutting slots for panels, etc., thick saws may be used, or the saw may be made to wabble by placing it between two beveled washers, as shown in Fig. 5.

The saw table has an inserted portion, C, held in place by two screws which may be removed when it is desired to use the saw mandrel for carrying a sticker head for planing small strips of moulding or reeding.

(Figs. G and T.j Tlu' head for lioldiiig the moulding knives is best made of good tough brass or steam metaL The knives can be made of good saw steel about ^ inch thick. They may be filed into shape and afterward tempered. They are slotted and held to their places on the head by means of i-inch machine screws. It is not absolutely necessary to use two knives, but when only one is employed a counterbalance should be fastened to the head in place of the other. All kinds of moulding, beading, tonguing and grooving may be done w^ith this attachment, the gauge being used to guide the

Turning Fluted Work.

edge of the stuff. If the boards are too thin to support themselves against the action of the knives they must be backed up by a thick strip of wood planed true. The speed for this cutter head should be as great as possible.

Fig. 8 shows an attachment to be used in connection with the cutter head and saw table for cutting straight, spiral or irregular flutes on turned work. It consists of a bar, D, carrying a central fixed arm, and at either end an adjustable arm, the purpose of the latter being to adapt the device to work of different lengths. The arm projecting from the center of the bar, D, sup-

IIO]\rE MECHANICS FOE AMATEUES ports an arbor Iia\'inj;al one end a socket foi* rccciviii^ii^ the twisted iron bar, E, and at the other end a center and a short finder or pin. A metal disk havini;- three spurs, a central aperture and a series of holes equally distant from the center and from each other, is attached by its spurs to the end of the cylinder to be fluted, and the center of the arbor in the arm, D, enters the central hole in the disk while its finger enters

Fig. 9.

Moulding Irregular Work.

one of the other holes. The opposite end of the cylinder is supported by a center screw. A fork attached to the back of the table embraces the twisted iron, E, so that as the wooden cylinder is moved diagonally over the cutter it is slowly rotated, making a spiral cut. After the first cut is made the finger of the arbor is removed from the disk and placed in an adjoining hole, when the second cut is made, and so on.

Figs. 9 and 10 show a convenient and easily made attachment for moulding the edges of irregular work, such as brackets, frames, parts of patterns, etc. It consists of a brass frame, F, supporting a small mandrel turning at the top in a conical bearing in the frame, and at the bottom upon a conical screw. A very small grooved pulley is fastened to the mandrel and surrounded by a rubber ring which bears against the face plate of the lathe, as shown in the engraving. The frame, F, is let into a wooden table supported by an

Fig. 11. Scroll Saw.

iron rod which is received by the tool rest holder of the lathe. The cutter, G, is made by turning upon a piece of steel the reverse of the required moulding, and slotting it transversely to form cutting edges. The shank of the cutter is fitted to a hole in the mandrel and secured in place by a small set screw. The edge of the work is permitted to bear against the shank of the cutter. Should the face plate of the lathe be too small to give the required speed, a wooden disk may be attached to it by means of screws and turned off.

Fig-s. 11, 12, aud 13 represent a cheaply and easily made scroll saw attachment for the foot lathe. It is made entirely of wood and is practically noiseless. The board, H, supports two uprights, I, between which is pivoted the arm, J, whose under side is parallel with the edge of the board. A block is placed between the uprights, I, to limit the downward movement of the arm, and the arm is clamped by a bolt which passes through it and through the two uprights and is provided with a wing nut.

A wooden table, secured to the upper edge of the board, H, is perforated to allow the saw to pass

Fig. 12.

Details of Saw.

through, and is provided with an inserted hardwood strip which supports the back of the saw, and which may be moved forward from time to time and cut off as it becomes worn. The upper guide of the saw consists of a round piece of hard wood inserted in a hole bored in the end of the arm, J. The upper end of the saw is secured in a small steel clamp pivoted in a slot in the end of a wooden spring secured to the top of the arm, J, and the lower end of the saw is secured in a similar clamp pivoted to the end of tlie wooden spring, K. Fig. 13 is an enlarged view showing the construction of clamp. The relation of the spring, K, to the board, H, and to

14 HOME MECHANICS FOPt z\MATEUES

the other part is showu iu Fig. 12. It is attached to the side of the board and is pressed upward by au adjusting screw near its fixed end.

The saw is driven by a wooden eccentric phiced on the saw mandrel shown in Figs. 4 and 5, and the spring, K, always pressed upward against the eccentric by its own ehisticity, and it is also drawn in an upward direction by the upper spring. This arrangement insures a continuous contact between the spring, K, and the eccentric, and consequently avoids noise. The friction surfaces of the eccentric and spring may be lubricated with tallow and plumbago. The eccentric may, with advantage, be made of metal.

The tension of the uppc^r spring may be varied by putting under it blocks of ditferent heights, or the screw which holds the back end may be used for this purpose.

The saw is attached to the lathe by means of an iron bent twice at right angles, attached to the board, H, and fitted to the tool rest support. The rear end of the sawing apparatus may be supported by a brace running to the lower part of the lathe or to the floor.

The simple attachments above described will enable the possessor to make man^^ small articles of furniture which he would not undertake without them, and for making models of small patterns they are almost invaluable.

WOEK BENCH AND TOOLS FOE WOODWORK

The first thing rexpiirc^d by the amateur workman is a bench with a few tools for wood working. The bench need not necessarily be a long and heavy structure like

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a carpenter's bench, as the work to be done by the amateur is mostly small, requiring but little material and small room. A table like that shown in connection with the simple lathe will answer, or the rear portion of the lathe table may be used as a bench. A small wooden vise is secured to the side of the table near the left hand end, and in the top of the table is inserted a common flat headed wood screw, which may be screwed down even with the top of the table, or raised i or :i inch, as the work ma^^ require. This screw takes the place of the usual bench dog, and holds the end of a piece of wood while it is being planed. Two planes are required to begin with, a jack plane and a smooth plane. A good fine cross-cut saw will probably answer for all ordinary sawing, and it may be used as a rip saw when only a little of this kind of work is required. Two chisels, one f inch, the other ^ inch, and two gouges of about the same width, will be needed. A hammer and a screwdriver, together with a brad awl and a foot rule complete an outfit that will enable the owner to do a great deal of work.

Of course a good oil stone should be at hand for sharpening the tools, and they should be kept shai'p.

Chisels and plane irons must be held at an angle of about 60° to the surface of the stone and moved back and forth on the stone until an edge is produced. The straight side of the tool must be kept from the oil stone.

While the tool is being sharpened the oil stone must be lubricated with a few drops of sewing machine oil or bicycle oil. When the tools need grinding it is advisable to have the Avork done by a competent workman.

The plane irons are set so that the edge is seen all the A\'av across the Avood of the plane and secured by driving in the wedge. If the tool projects so as to make a thick shaving, the wedge is loosened slightly and tlie iron is made to rise slightly by tapping with a hammer on the top of the plane. The iron may be adjusted laterally by tapping the iron on one edge or the other near the top, and it may be forced downward by a few light taps on the upper end.

After some observation — ever}^ boy has opportunities for observation — and after practice, the amateur will be able to do an ordinary job of carpentry, and he will seek after a few more tools, such for example as a try-square, a bit-stock and a few bits, a few clamps and a glue pot. He can then enter into the work heartily, and not only make needed repairs, but construct many plain little articles such as boxes Avith hinged covers, cabinets, screen frames, etc. The main requirements are to construct each part as carefully as possible, to assemble the parts with equal care, and to never use plugs or putty, or in other ways patch up for bad workmanship. If a mistake is made, it is generally better to throw the part away and begin again rather than to patch.

WHITTLING

The boy who is a good whittler will make a good mechanic, or will at least understand mechanics well enough to know a good job from a poor one, and will be able to help himself in many an emergency. Real proficiency with a jack-knife implies a knowledge of mechanics and exhibits an ai^titude for mechanical work which only needs opportunity and encouragement to reach a useful stage of development.

A jack-knife is a very simple tool, but without doubt

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it is more generally useful tliau au}^ other. For whittling, an ordinary two or four-bladed knife should be selected. It should have a good-sized handle and its blades should be fine and well tempered. With the knife should be purchased a fine, sharp oil stone, and the knife should be kept sharp, as it is impossible even

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^1 i

Fig. 14. Knives adapted for Whittling.

for an expert workman to do good work with a dull knife.

In sharpening the knife, the blade should be kept at an angle of about 20° with the face of the stone and rubbed back and forth the full length of the stone about an equal number of times for opposite sides of the blade, until it appears to be sharp, the stone meantime being lubricated with water or oil ; then it may be stropped like a razor on a strip of leather until it is literally as sharp as a razor.

In whittling curious and ornamental objects, seasoned straight-grained white pine should be selected.

The piece should be a little larger than the finished work, and the design should be laid out in pencil on one side of the block, when it can be sawed out with a scroll saw. If the form can be traced on the edge of the work much whittling may be avoided by doing more sawing. The knife work may now proceed. It is well to begin with the heavier portions and finish with the lighter portions.

As much should be done as possible without the use of sand paper. If it can all be done without sand paper so much the better. It will sometimes be found necessary to put on the finishing touches with a piece of very fine sand paper. Blades of different forms are found useful, and in some kinds of work a penknife blade which has been broken off rather short will prove exceedingly useful when the blade has been repointed.

The saw used for shaping the work may be like the one on pages 12 and 13, or one of the small scroll sawing machines so much in use at one time would be still better.

A very pretty example of whittling is the chain whose links are formed from a single bar of wood of 0-shaped cross section. To make a good job the bar should be evenly spaced, and the links drawn on the sides of the bar. Then holes are bored diagonally through the bar. At the angle the cutting proceeds slowly and cautiously, finishing the link as far as possible before it is cut loose. If any sandpapering is to be done it should be done as far as possible before the link is cut loose. In the example shown, only a iDortion of the wooden bar has been formed with links, the remainder being left to give an idea of the method.

It is more difficult to whittle a pair of pliers from a

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single piece of wood, so that the jaws work freely, and at the same time the joints are neat.