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Are you worried by any question in Engineering or the Mechanic Arts? Put the question into writing and mail it to the Consulting Department, TECHNICAL WORLD MAGAZINE We have made arrangements to have all such

ns answered by a staff of consulting engincers and other erperts whose services have been stecially enlisted for purpose. If the question asked is of general interest, the answer will be published in the magasine. If of only personal interest, the answer will be sent by mail, provided a stamped and addressed envelope is enclosed with the question. Requests for information as to where desired articles can be purchased, will also be cheerfully answered,

quired. Next, the wrench is bent to the “S” shape, and finally ground.

A Remedy for Cross-Threading
How can I prevent cross-threading ?-T.
A. E.

Making a Wrench Can you suggest a handy wrench for use on carriage or buggy?-A. H. R.

What is known as the “S” wrench is a standard shape which is probably the best for all-around purposes. If you cannot buy one in your local hardware store, a blacksmith can easily turn one out. It is made as follows:

Round the ends of a piece of buggy spring or steel tire of suitable length. About one inch from each end bend the piece of steel and fold over, as the drawing indicates. Punch a hole in each end, and cut out to each end, as shown by the dotted lines. These openings serve as the slots with which to grip the nuts. They may now be made the size re

REMEDY For Cross-THREADING.

The thread of a screw, it will be observed, does not begin immediately, but some little distance up the metal. It begins with a gradual start and finally makes a complete turn or thread. This slow start often results in the nut's becoming wedged at an angle with the screw. To obviate this difficulty, the imperfect start of the thread should be removed with a file.

To Make a Strong Glue I should like to have you print a formula for gluing emery to wood or metal.0. H. S.

HANDY S-SHAPED WRENCH.

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Take equal parts of white rosin and is covered with fire-clay, to prevent the shellac, and melt them together. When gases from escaping, and the box is this has been done, add a quantity of car- closed and heat applied. bolic acid (in crystals) equal to the This method is most valuable in hardquantity of rosin or shellac used. The ening milling-machine cutters, gauges, cement thus made has great adhesive and taps where it is essential that the dipower.

ameter and pitch remain unaltered. For the sake of economy, a number of pieces

should be packed together. The pieces Constructing Stairways

are wired with iron binding wire of suffiIs there a way of laying boards in stair- cient strength to sustain the weight when building to minimize the wear?-H. H.

the wire is red hot. One end of the wire The boards for steps are usually

is allowed to project over the edge of laid transversely—i. e., at right angles

the box and is covered with clay. Test with the direction of travel up and down

wires are inserted through holes in the the stairway. The result is, the wear

cover of the box, as in annealing. The time the material is allowed in the fire is determined by the diameter of the tools in the box and by the nature of the work. For tools 1/2 inch in diameter, burning should continue from 1 to 1/2 hours after the wires are red hot; for pieces 2 to 3 inches in diameter, 212 to 4 hours. On removing from the box, the tool should be immersed in raw linseed oil, and worked about in this liquid until the glow

is gone. If the piece of steel thus being WAY TO LAY Stairs.

hardened is more than an inch in diamcomes across the grain. The boards for

eter, it should be reheated on removing

from the bath, to a temperature of 212°, steps should be placed as shown in the drawing. The grain will thus run in

to prevent its cracking. the direction of the traffic, and the length of service of the material em

Making a Shaving Horse ployed will be greatly prolonged. Only

I should like to make a shaving horse. narrow boards, threaded into each other,

Could you give me a brief description of how as indicated, should be used. Oak or to do so, with some simple drawing ?-T. H. W. maple makes the best material for the

Take some good two-inch plank of conpurpose.

venient length; and construct a bench

some 18 inches high, supported by stout Process of Pack Hardening

legs set at a slight angle, as indicated in Will you describe the process of pack hard

the diagram. In constructing the bench, ening?-F. M. P.

allowance should be made for the slantThe article to be hardened is packed

ing platform b, which will overlap the in an iron box with carbonaceous mate

end of the bench. The clamp a should rial. This carbonaceous material is

be made of tough hardwood that will not charred leather, ground very fine, being

split. The shank or support f is an exreduced to pieces each half as large as a pea, and mixed with an equal volume of wood charcoal. The iron box, which should be large enough to allow ample room for the piece to be hardened, is covered on the bottom an inch deep with this packing material. Next the metal is laid on this, and the box nearly filled with more packing material, which is tamped down. Lastly, the space remaining

SHAVING HORSE.

tension of the clamp. A hole must be ber of the American Society of Heating cut in the platform for the insertion of and Ventilating Engineers, at its meetthe clamp. The shank should be pierced ing in Chicago last July. with several holes so as to allow for The system herein described differs larger pieces of wood. The treadle g, from the ordinary type in that ventilation at the bottom, is kept in place by a peg is satisfactorily secured for all the rooms at h.

of the house. Any up-to-date furnace, To put the finished horse to use, the large enough for the service it will be workman inserts the piece of wood under called upon to perform, may be installed. the edge of the clamp, and presses back Fresh air should be obtained directly for upon the treadle with his foot. The wood the furnace, which ought to be centrally is thus securely caught. The shaving located. The warm-air chamber or box can now be done with the drawing knife, need be connected with the registers in more easily and expeditiously than would the various rooms by only one-half the be the case if a vise were used.

number of pipes ordinarily used. The

basement is not filled with hot-air pipes, Improved Furnace Ventilation

as is the custom in present modes of hot

air heating. What is the latest and best method of ven

The illustration shows the method of tilating with hot-air heating ?-H. S. G.

connecting the wall pipe to the top of the There are numerous methods, each of

improved side-wall register. The method of pipe construction in the basement is also indicated. The registers in the various rooms are provided with a double metal box. Between the inner and outer casing there is an air-space. A ventilating opening is provided for. This opening sucks the atmosphere from the heated room and conducts it through the airspace upwards. Where single wall pipes are used, the air passes around the pipe. Where double wall pipe is used, the air passes between the two casings. The heated wall pipe causes the air of the room to move off rapidly. Vent pipes should conduct the bad air to a chimney flue. This flue should be used for this purpose only.

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Wireless' Greatest Distance To what distance can the wireless telegraph be successfully operated ?-F. N.

This is a question that cannot be answered very definitely. Messages are supposed to have been sent across the Atlantic, by Marconi. Vessels at sea several hundreds of miles apart, readily communicate with one another by wireless. The efficiency of the service varies considerably with place and atmospheric conditions. What the instruments in use to-day are fully capable of doing, cannot be stated. Results from day to day, with the same instruments, show very great discrepancies.

IMPRCVED FURNACE HOT-AIR SHAFT.

which has advantages peculiar to itself. Probably one of the most satisfactory systems is that recommended by a mem

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Taking an Indicator Card

Then slip the paper down into place; Explain in full the method of taking an in- pull and adjust so that it fits snugly; dicator card.-R. C. T.

and bend the edges back as in c. The The instrument should first be exam- cord is then hooked on to the reducing ined and put into proper condition and motion, and the drum takes up its moveadjustment. This should include the fol- ment with the main piston. The cock is lowing points: (1) The joints should then opened to the end of the cylinder all work freely, but with-. out lost motion; (2) the piston should not bind, nor should it be so loosely fitted as to allow serious leakage. A slight leakage, however, is better than too snug a fit; (3) the working surfaces of the barrel and piston should be carefully wiped and oiled. This should be repeated from time to time when a series of cards is being taken. The joints of the pencil motion should also be lu- A bricated with clock oil as

TAKING AN INDICATOR Card. often as may be required. (4) The pencil points should be sharp- from which the diagram is desired, and ened and the screw stop so adjusted that the pencil immediately takes up its mothe point can rest only lightly on the tion corresponding to the varying prespaper.

sures of the steam. The indicator pisThe operation of taking the card itself ton should be allowed to work in this is briefly as follows:

way for a few strokes, or until everyThe indicator is attached to the cock; thing is warmed up into working condia blank card is placed on the drum; and tion. the cord connection is adjusted so that the When everything is in readiness, the drum will have the proper stroke with pencil motion is moved up against the out coming against the stop at either stop so that the pencil, resting lightly on end. In attaching the blank card, the the paper, will trace its path for a commost convenient way will be to bend the plete revolution, or longer if desired. sheet of paper around and grasp both Then remove, and shut off the indicator edges between the thumb and forefinger from the cylinder. This will connect it as at AB. Then slip over the drum and with the air; the indicator piston will under the clips, so that the latter will come to equilibrium under atmospheric come outside the paper as shown at PQ,b. pressure; and the atmospheric line may

then be drawn. The drum connection is then unhooked, the paper removed, a fresh one replaced, and the next card taken when desired.

If one indicator is used for both ends of the cyl

inder, both cards should be Pra

taken on the same paper with as small an interval between as possible. The

cock is swung oder for one ADJUSTING AN INDICATOR CARD.

end, and the card taken;

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and then immediately swung over for the main piece A. At one end of this eightother end, and the second card taken inch piece, drive a staple D; at the other without loss of time. The cock is then end, a hook G. Next take a rope, fasten closed off, connecting the indicator with a ring at one end F, and run around the the air; and the atmospheric line is then crank-shaft and through the staple, as indrawn.

dicated. The apparatus is now ready for Each card, as it is removed from the use. indicator, should be marked with suffi Thrust the point of the tapering stick cient data to identify it, and make possible its use for the purpose intended. This should include at least the following items: (1) Cylinder; (2) end from which card is taken ; (3) revolution ; (4) scale of spring; (5) if a series of cards are being taken, the time and serial number should also be set down.

The various other items usually printed on the back of the card may be filled in at a later time, as may be convenient. When cards from both ends are taken on one paper, we must be able to assign each to its proper end of the cylinder. The surest way of determining this is to shut off the connection to one end of the

Mission-Style Library Table. cylinder entirely, and then take the card from the other end. It will thus appear into the shock, and bind the rope around how the card from this end lies on the paper—whether with admission line to

the latter by catching the ring on the

hook. On turning the crank, the rope the right or to the left; and this will

will wind itself about the larger stick beshow how to mark the entire series of

tween the washer and the crank. cards taken with the same arrangement of reducing gear, etc.

Making a Shock-Binder Could you suggest a simple shock-binder for farm use?-T. J.

Making a “Mission" Table Will you please explain the construction of a "mission” library table large enough for three or four persons to gather about?T. J. M.

The accompanying drawing gives a general view of a standard style of such a table as you speak of. One whose top is about 48 inches long and 28 inches broad, will doubtless answer your purpose. The height should be about 29 inches. Legs 3 inches square, set 194 inches from the corners, will offer a firm support. The shelf supporting the trough for books, is set 10 inches from the floor. A full drawer may be put in, or small, corner drawers, according to taste or needs. The board for the top is 1974 inches thick. Pegs should be used throughout, instead of nails. Smoothplaned oak makes excellent material for furniture of this kind.

T he staining to a dark hue may be done after the construction is completed.

DEVICE FOR TYING Shocks.

Procure a stout strip, some forty inches in length and tapering. This should be squared, and a crank affixed, as indicated in the accompanying drawing. This crank is of a simple kind and may be obtained in any hardware store. Take a stout piece of wood, eight inches long, through which a hole has previously been bored, and force it with washer C on the

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