CRESCENT SHEET STEEL PARTS.

REMINGTONFLUSH JOINT.

The makers and users of sheet steel parts claim for them as advantages over drop forgings that they are of uniform size, shape and gauge; that they weigh less; that there is but little waste of material, and that as many as ten thousand operations can be done by one operator in a day. Of course, the cost of production is thus made lower as compared with the cost of production of drop forgings, which require a large amount of machining on lathes and other milling machines, necessarily slow in operation. The makers of these stamped form-drawn parts claim that through the largely increased use of their goods American makers have been able to produce lighter bicycles than they were formerly able to produce with the use of drop forgings for their connections, that the popularity of the bicycle in this country is due to the present popular prices at which they are sold, and that these popular prices are largely due to the low cost of sheet metal parts. They also claim that after the sheet metal parts and the tubes of the bicycle are brazed together, they then form one continuous piece, to all intents and purposes as good as if a solid drop forging were used. The average thickness of the sheet steel used in making these stampings is from1⁄16to ⅛ of an inch. Some very remarkable forms are produced in steel stampings, notably a crank-hanger of 2 inches in diameter, having two projections or lugs to carry the rear forks, and the two outer projections or lugs to carry the large lower main tubes and the large diagonal stay of the bicycle frame.

Until the cycle show of 1895 but little else had been heard of for making frame connections except drop forgings, but a revelation was placed before the eyes of the master mechanics of rival cycle making concerns who visited the show when they inspected the ’95 models of the Crescent, made by the Western Wheel Works of Chicago. Here were shownfor the first time steering head connections, crank-hanger, seat pillar and rear fork ends all made of sheet steel and brought to perfection by a combination of the methods of stamping, drawing and forming. But even these parts did not surprise these experts of the trade so much as a sprocket wheel shown. Here was a sprocket wheel struck up out of a flat disk of sheet steel, its edge turned and drawn over, thus doubling the width of its face, and on this double edge were afterward milled the teeth. Of course, the parts shown in those days conformed in general outline to the construction then in vogue. The Crescent people, however, have continued to use this method of making frame connections; and while a large number of other makers have adopted this form of construction, they, as the pioneers of it, are still the leaders. Their production is enormous, their gross sales last year being 83,000 bicycles, and certainly if this method of making frame connections were not closely akin to absolute perfection their troubles under the guarantee would be enormous, and would swamp them. This year their frame connections are all of the flush joint style. The head connections are formed out of sheet steel reinforcements, having a large bearing and brazing surface.

Their crown is formed of two pieces of sheet steel drawn to a hollow arch shape. These two pieces are placed together and the ends come into a spearhead of capital letter A shape, two holes being drilled on each side in order to allow the brazing spelter to flow through the crown freely when the forksides are brazed to them. Before these forksides are brazed to the crown, however, a third piece of arch shape steel is forced down over the two pieces forming the crown. This third piece of sheet steel is lapped underneath the bottom of the crown, so that when the three pieces are brazed together they practically form one continuous piece. A drawn lug projects over the top of the crown, and into this the fork stem, the end of which is shaped to conform, is set on top of the crown and pinned and brazed to the lug and crown.

Inside of this fork stem, in order to strengthen it, is also placed a sheet steel liner, extending six inches into the length of the stem. The whole construction of this fork crown and stem is one of the strongest in use.

A test made of this form of fork construction at their works showed that by supporting it horizontally on a frame, the supports being about six inches above and below the crown, it sustained a weight of 3,500 pounds without deflection.

The crank-hanger is of the one-piece construction, and is made from a five-inch disk of sheet steel, which is drawn into the shape of a tube through the medium of five separate operations; and this tube, when finished, is about two and a half inches in diameter. The four lugs to carry the rear forks, lower main tube and diagonal stay, are then drawn and formed upon it, this, however, requiring a total of twelve operations to complete it. The part requires annealing after every operation, the process of drawing and forming having a tendency not only to lengthen the fibre of the metal, but to harden it. The quality of the metal used in making this hanger must necessarily be of the best, and after the metal has survived all these operations it must also necessarily be perfect, for any crack, seam or flaw in it makes it useless and consigns it to the scrap heap.

MAKING CRESCENTCRANK HANGER.STAGE 1.

MAKING CRESCENTCRANK HANGER.STAGE 2.

MAKING CRESCENTCRANK HANGER.STAGE 3.

MAKING CRESCENTCRANK HANGER.STAGE 4.

MAKING CRESCENTCRANK HANGER.STAGE 5.

The seat-pillar lug or group, while not altogether seamless, is of the one-piece construction, also having the three lugs drawn and formedupon it. The rear fork jaws are also stamped out of crucible sheet steel, and are of what is known of the semi-hollow construction.

The little brace which is usually placed between the rear forks and back of the crank-hanger and called a bridge, is generally made by a short piece of tubing and brazed to the two rear forks. The makers of the Crescent, who use a D-shaped rear fork, which is drawn to a round shape where it is offset and where it joins the rear lugs on the bottom bracket, make this bridge of two pieces of sheet steel, which are pinned and brazed together and are carried down on each side of the rear forks for several inches in a peculiar lipped shape. It is an expensive method of bridging the rear forks, but greatly adds to the strength at this point and prevents any serious lateral deflection of the frame when the pressure is applied to the cranks on either side. They are the only makers who form their sprockets out of a piece of crucible sheet stamped steel. As it is now made to fit a three-sixteenth chain, which is so popular and which they use, they do not show the wide opening on the flanges of the sprocket between the teeth.

WORKING DRAWING DIAMOND FRAME MODEL.(See Page 52).

Fig. 1shows the circular steel blank as made by the first operation on a large double action drawing press. It is then drawn into a cup shape as shown infig 2. The practicability of the result obtained is noticeable at once. The edge of the cup is smooth, and there is no wrinkling, cracking or buckling in the steel, and it is still of the same thickness as the original sheet. It is again drawn by successive operations into a cylindrical shape as shown infig. 3. The end is cut off, and the next operations form the lugs as shown infig. 4, until the final operation gives the result as infig. 5, when the crank-hanger is ready for the joining of the frame tubes. It requires ten days to complete a finished crank-hanger. A marvellous piece of work this certainly is, and it is doubtful if the result obtained in stamping this crank-hanger can ever be equalled by the working of forgings, and the whole result might be summed up by saying that it is “distinctively Crescent.”

After the drop forgings or stampings are carefully finished by hand or machine, they are carefully cleaned to remove any scale or oil. The tubes having been cut to a proper length, are then closely fitted into the open joint of the forging or stamping connection. In order, however, to hold them securely in place they are pinned through. They are then taken to the brazing furnace. This furnace consists of an open stand, about three feet high, covered with fire brick, pumice stone or coke the purpose of which is to retain the heat. The heat is produced by a mixture of atmospheric air and gas or gasoline, which is controlled by the operator, and supplied by a blower or fan. The flame is applied directly to the joint which is to be brazed by a steel tube, resembling a Bunsen burner, and uses about nine parts of air and one of gas. The combustion or air and gas in the brazing apparatus is about the same mixture as is used in a gas engine. The joint having been brought to the necessary heat, which must in a large measure be left to the judgment and experience of the operator, powdered borax is applied first, the object being to remove any oil or other foreign substance which might interfere with the uniting of the two metals. The borax on being applied flows almost like water. The spelter is then applied, producing a flux, and owing to the expansion of the connection and the tube it readily flows between the joints. The whole operation after the required heat is obtained usually occupies five or six seconds, theobject being to secure a joint as rapidly as possible, provided the brazing metal is equally distributed. The gas is then shut off. The supply of air is continued only in order to rapidly cool the joint, the object of this being to prevent the flux from disintegrating and losing its position in the joint. If a brazing has not been rapidly and properly cooled the jar and vibration which the frame receives when in use on a bicycle is apt to cause particles of the flux used in brazing to become loose and rattle in the tube. Necessarily under this operation what might be termed a congregation of scale and the brazing flux is gathered on the outside of the joint. This is afterwards removed by the use of sand blast or pickle, and last, but not least, by hand filing.

WORKING DRAWING DROP FRAME MODEL.(See Page 52.)

What is known as “brazing spelter” is really a misnomer, and should be called brazing solder. Spelter is the crude product from which refined zinc results. Brazing solder is a combination of copper and spelter first cast into slabs or ingots, then placed into large mortars and pounded by a heavy pestle by hand, and, strange to say, that in all our recent developments in metal work no method can be found to supersede this method of manufacture, as this is the original method of making it.

There are altogether about eight grades of brazing solder, ranging from what is known as the coarse long grain to extra fine grain.

The first result of the pounding operation is the coarse long grain which comes out almost in shreds; by further pounding the shreds are produced, and the result is the fine long grain. From this operation comes the rough grain, the first being coarse long grain, the next medium, then fine and finally extra fine. The proportion of extra fine long grain to the other coarser grades or varieties is only about ten per cent. of the total, consequently making the latter grade the highest in price. The various grades are separated by sifting through a sieve. The running qualities of this solder are affected by the larger or smaller proportion of copper used in the composition. The more copper used the more heat required to melt it, the reverse being the case where more spelter than copper is used.

On bicycle frame work where the surface is largely exposed, the coarse varieties can be successfully used, but for the fine work where little heat can be used, and where the tubing is of extremely light gauge the extra fine grade, which is known also as the quick running solder, gives the best results.

Wire spelter, which comes in coils, has become very popular on account of its lessened cost, its cleanliness, and also because it is not so wasteful as loose spelter, and can be conveyed directly into the joint by the operator as soon as it has reached the melting point.

EAGLEDROPPED FORGEDFLUSH JOINT.

Another method that is somewhat new is known as liquid brazing, which is nothing really but a special treatment of the joint plunged into molten spelter, and out of which the joint comes surprisingly free from scale, a cleaning by a wire brush being about all the after treatment necessary. The process is a secret one, and the surrounding joints are covered with what is known as the anti-flux, so that the spelter will not adhere there, but joints to be united, of course, are covered with a liquid flux as in the old way.

The makers of the Union produce their flush joints by using what they call pocket brazing. This mode requires the forming of a series of pockets in the projecting ends of the brackets, which may be oval, circular or of any desired shape, although the oval has been found themost convenient. Before the tubing is completely fitted over the bracket arm the pockets are filled with flux, and immediately upon the application of the heat the brass begins to flow and with astonishing evenness, so much so, in fact, that when after cooling, joints are cut out, the brass is found as uniformly distributed as if laid on with a brush. Moreover, no considerable amount of brass flows out of the joint and no filling is necessary. Less heat is required for the reason that the brass is placed where necessary and the parts need not be dangerously heated to cause the brass to flow in. The pocket corrugations are found to stiffen the machine to a marked degree. Taken all in all it is a sure, clean and highly ingenious braze.

THE KANGAROO.

Apropos of frames, we reproduce here a cut of the Kangaroo, which was the first bicycle driven by chains. The earliest samples of theRovertype antedated it, but there had been no previous commercial use of a chain on a two-wheeler, for the Otto accomplished nothing commercially. The Kangaroo was brought out in 1884, and attracted attention because its makers were fortunate enough to break with it the 24-hour record, which had been standing unchanged since the early years of bicycling. This success, together with energetic pushing, gave the Kangaroo quite a run for a couple of years, when the rear-driver put an end to its career. It was brought to this country in 1885, but hardly obtained a firm foothold for even the time being. The forks were bowed out widely, there being no attempt to reduce width by lessening the “dish” of the wheel, and consequently the tread was what would have been considered in later years outlandishly wide. The wheel was usually 36, geared to 54, with a 22-inch wheel behind. The chief drawbacks were that the sprocket bearings were ill-supported, as a shaft could not be run through the wheel, and so they did not stand well under the twisting strain; the backlash was unusual, all the objectionable features of chain driving, which had not at that time been modified by improved construction, being increased by having it on both sides. TheKangaroowas also heavy and clumsy, and for some reason never satisfactorily explained it had a peculiar liability to side-slip.

A difficulty which has hung about wood frames from the first is that of the joints, nor could it ever be questioned that appearance was not in favor of the wood frame, although, on the other hand, it must be admitted that objections to appearance are soon overcome in cycling construction if there is a good balance of points on behalf of a thing. Perhaps the best-looking of the wood frames was that produced by the “Old Tonk” people, who turned to account the beauty which may be had from several layers of wood placed together. The wood frame has succeeded quite as poorly abroad, and it will probably remain forgotten until, some years hence, it comes up again as a novelty of the season. The Bamboo Cycle Company has just failed in London, and theIrish Cyclistexpresses surprise that it remained afloat so long as it did. Not a single expert or a single cycling journal, says the writer, ever referred to the bamboo frame except with disapproval, although it was well advertised and the parties interested were ready to pay for opinions. A considerable number of the bicycles were sold, but the rarity of their appearance on the road suggests that even those who bought them did not use them much. Now that the company has failed, this writer says: “It is to be hoped that no one else will be so foolish as to endeavor to accomplish the impossible task of proving that a bamboo stick is as useful as a steel tube.”

The two working drawings of frame are from W. C. Boak of Buffalo, and are reproductions of his blue-print drawings used in designing and drafting 1898 frames, and show on the men’s model the exact drop (3 inches) of the crank-hanger from a line drawn between the front and rear axles. The length of head is five inches, and the wheel base—the distance between front and rear axles—is 4111⁄16inches. On the ladies’ model the crank-hanger is dropped 2½ inches, and the head is 7½ inches, the wheel base being 41⅞ inches. The height of both frames is 22 inches. The small numbers in the illustrations show the angles of the frame and indicate the sizes of the tubing used. The designs call for the use of D-shape tubing for the front and rear forks and backstays and round tubing throughout the rest of the frame.

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