He Built a Better Slingshot
CASTING ABOUT for some activity with which to while away his enforced leisure, Carl Tinker, a retired engineer in Lapeer, Michigan, has combined two hobbies to produce a thriving mail-order business in slingshots.
Having built and operated a complete home workshop over the pre-retirement years, it was obvious that much of Tinker's time would be spent there in some endeavor, worthwhile or otherwise. Recalling his boyhood slingshot made from a willow fork and an old inner tube which he recently had come across and experimented with in the back yard, he quite naturally put the two things together in his mind. Going over the weaknesses of the product as fashioned by jackknife and string, he bettered it in every way in his workshop and today Tinker's "Deerslayer" slingshot is known throughout the sporting fraternity as being among the best made.
Although the market for slingshots specifically is very definitely limited, the same small-shop methods may be used to produce any article of similar basic character for today's booming market in sports items. All one has to have is an idea, a small talent and capital outlay, and a whale of an interest in the subject at hand. Tinker makes slingshots and is perfectly willing to have you make them, too. But maybe you have a better idea.
FIRST OF all, Tinker recalled that his willow fork had been too light and fragile for accurate, sustained shooting. He therefore decided to die-cast the frame from an inexpensive, low-temperature metal, and to this end made two fitted dies with simple hand and lathe tools. Fashioning these dies, around which most of the operation is centered, is indeed a job for the craft-minded, since it is meticulous work requiring some familiarity with or reading about the factors involved. These include metallurgy, temperatures, pressures, and casting in general. However, the cost of such dies made in the professional market is very high, which means that if the amateur can manage to cut his own with home tools he has surmounted one of the major expenses of getting into production.
Once the dies had been cut, Tinker decided upon a cheap zinc alloy for his metal, since it had strength, moderate weight, and a low melting point which would enable him to use it in a simple, home-built furnace. Also, the metal was inexpensive, not on the critical defense list, and could be obtained easily through local supply houses.
The furnace he installed in his garage-become-workshop uses ordinary cooking gas as its combustible component and develops about 700 degrees Fahrenheit temperatures to render the metal molten. Its cauldron is a discarded steel bucket of the thickness formerly used for boiling sap or rendering lard; its insulation is asbestos sheets wound with wire.
Mounted in a tubular, sliding framework, the dies come together with the depressions forming the slingshot frame cupped between them. When closed, the liquid metal is forced through a duct into this depression by air pressure. The pressure is then turned off, the molten metal has instantly cooled, and the dies are drawn apart by a hand-operated lever.
Tinker immediately learned some valuable rules about safety in operating his home furnace. Since the air pressure had to be sufficient to force the metal through the tubes and into the dies, there was always the possibility of a blowout along the way or through any overlooked spaces, however small, in the dies themselves. Realizing this, he equipped himself with the routine safeguards of heavy mask, clothing, and gloves. However, except for a few flash leaks of the metal which sprayed the ceiling harmlessly, there have been no accidents. He maintains a comfortable safety factor by keeping the little ¼-horsepower motor which produces the air pressure operating just over the minimum required.
THE NUMBER of small manufacturing kinks revealed in the building and operation of a production apparatus even as simple as this die casting rig is almost unlimited. For instance, Tinker found that it was necessary to water-cool the dies, and then that in order to provide the proper release of the cast metal from the die nearest the supply source a further heating at the point of release was needed. Thus an extra jet of gas was rigged to be applied at the "goose-neck," or central metal injection point in order to keep it at the temperature which would insure a smooth release.
All such details may make the project sound complicated and difficult, but Tinker has managed to operate it from the manufacturing as well as the commercial end strictly as a spare-time project, giving much of his day to his engineering research. He states emphatically that the difficulties encountered were the really enjoyable parts of the whole business and that anyone with a basic knowledge of metals who likes to putter with details should be able to duplicate his die-casting rig for simple shapes with no trouble and little expense. The number of items that can be so cast, from simple metal parts to more elaborate products such as a toy steam engine, which also has been made in this shop, is almost unlimited.
TO PROVIDE the power for the slingshot, Tinker uses not the discarded inner tube of cherished boyhood memory, as many people thought before they tried the Deerslayer, but pure gum rubber. This rubber is purchased in 1/16-inch sheets from a supply firm and is run through a simple cutting machine. This slices the rubbers to strips 5/8-inch wide and does it so fast that the single operator can cut several hundred rubbers at a time, thus providing again the amount of finished material through a single operation which makes this a profitable enterprise.
Another part of the home-made slingshot which was always a weakness was the tendency to break or come apart at the places where it was tied, either to the frame or the leather pouch. To eliminate this, instead of using a cutting material such as wire or twine, Tinker has fastened the rubbers to the calfskin leather pouch by winding Scotch tape around the stretched rubber after it is doubled through the slits in the leather. Shopwise, it was most expedient to improvise a small gadget by which the rubbers could be stretched, then rotated in order to wind the tape tightly around them. At one sitting, Tinker can cut and tie several hundred rubbers and pouches, a far cry from the hour's labor of two lads, one stretching, one tying with bits of butcher-shop twine.
To fasten the rubbers to the frame, all tying material has been dispensed with merely by leaving a small groove at the top of the frame handle in which the doubled rubber is placed and a matchstick or other small piece of material inserted in the loop formed by the rubber. Thus, when the rubber is pulled in the ordinary way, the loop closes, is drawn tightly against the frame, and provides a secure clamp for itself. Further, it can easily be loosened and adjusted if necessary.
TINKER HAS no intention of expanding his sales beyond the level of personal comfort. In order to sell the article in the small—but most profitable per unit—volume desired, he has resorted to the mail order method and found it most advantageous. The 130 per cent markup of the wholesaler and retailer thus becomes part of his take. He retails the Deerslayer at $2, with extra rubbers and a supply of ammunition included.
Tinker's method of arriving at this price may be of interest: He quoted his modest job-lot price to wholesalers, asked them their price to distributors, the distributors' price to retailers, and the retail price to the public. After seeing the whopping cut which these persons absorb in their capacity of providing the merchandise to a mass market, Tinker decided that he would add their functions to his operation, since he did not intend to cater to any but the "class" trade and was not interested in selling a very large quantity annually. Thus, his individual margin of profit is higher thereby, and the total profit about the same; in other words, the same profit, less work.
The various sporting magazines have been used for the most part as advertising mediums and the performance of each advertisement is carefully tabulated. A chart is kept, showing the placement of the advertisement, the wordage, and the response by areas, which has resulted in his getting the most from his limited advertising funds.
Packaging and mailing the product, as Tinker found to his regret as the sales volume mounted, takes as much time as the actual production, so at times a stray crony or member of the family has been pressed into service as stamp-licker or typist. A sack of steel balls is enclosed with each slingshot or, if they are not available due to metal restrictions, good marbles are substituted and the purchaser may write later for the steel shot. The forks of the frame itself, to provide merchandising color, are dipped in red lacquer, which has added to the sales. Thus the strange tastes of the buying public.
FOR CARL TINKER, not the least entertaining part of this game of operating his own business has been the variety of persons who have taken up the sport and have written to purchase one of the Deerslayers. Aside from the expected trapper and sportsman, these have included doctors, circus and fair operators, and diplomats. The midways of several leading shows are now stocking the slingshots in place of the more expensive and dangerous rifles which people fire at clay targets for kewpie dolls. As for the diplomats, who knows?
In addition to these amateur uses, the experts have actually taken the slingshots afield and bagged small game with them. However, there is no basis for claims of extraordinary power for any slingshot utilizing rubber propellents. At the most a pull of forty pounds is obtained, which is insufficient to give a foot-poundage to the pellet more than that obtained with an air rifle.
As an absorbing lesson in economics and production, the Deerslayers have indeed served their purpose. However, if Tinkers idea was to replace the willow variety with his own zinc and pure gum product, he has failed completely and is rather glad of it. Relatively few of his orders come from youngsters bent on breaking windows or scuttling the neighbors cat. Tinker knows that the real fun, both for the lads and himself, lies in the craft of making the weapon. The boy whittles the willow to test his skill at handiwork; Tinker's aim is the operation of his small business as a worthwhile means of relaxation rather than providing a livelihood or, certainly, trying to corner the market in that field. More power to the willow whittlers, he says, (although they'd do better with maple) and more power to all such tinkerings, we say.
Note: To account for inflation, multiply prices by 8 to 10.