CHAPTER VII

PRESS AND HAMMER FORMING OF HEAVY HOT AND COLD BAR AND SHEET STOCK IN DIES, TOGETHER WITH MANUFACTURE AND ASSEMBLING OF FINISHED PRODUCTS FROM SUCH

Making a Wheelbarrow Wheel

WHEN a new piece is to be produced in quantities, and the job has been worked through carefully, and decisions have been made on all the operations, tools, and fixtures needful, then it is sometimes a good thing to forget that there are such tools as drillers, lathes, planers, millers, and screw-machines, and remember squeezing tools alone.

Some things cannot be made by pressing and punching, hot or cold; but really, when we look the field over carefully, it will be seen that almost everything can be made of sheet or bar stock, in some forms of rolls or presses.

For a big thing, a wooden freight-car doesn't look at first like a press job, and for a little thing a wooden wheelbarrow wheel doesn't seem exactly fit for production from metal, with not a cut made on it.

It is not so very long ago since the pressed-steel freightcar became an established production. Metal wheels have been made for many years, but plenty of wooden wheels are still used, because it takes a long, long time to change existing practise, even when the new thing is not only best and cheapest in the long run, but is the lowest in first cost and by far the most durable of the two.

The expert machine designer should not let habit and custom hinder him from seeing more than one way to produce what he wants, yet he often does take the handy and costly way, because it is the way he knows best, and because others have gone the same way for a similar output. It is easier to do what has been done, than to do the best that can be done, and,

if one follows the old way, he escapes the stigma of experiment, and stands on the safe ground of established practise and conservative engineering. "Conservative practise" is a fine term, fine to capitalists, and to routine followers, and when some rule-breaking experimenter finds new and better ways of doing things, then conservative practise becomes dear in the other sense of the word. Sad to say though, sometimes the experimenter does not come out right, and then

FIG. 197.-Parts of wheel ready for assembling.

the old-way advocates can be happy and say, "I told you so" with complacent joy.

Operations on Wheel

The parts of the eight-spoke metal wheelbarrow wheel are shown in Fig. 197, and consist of the cored cast-iron hub, two hot-pressed steel flanges, four bent spoke parts, two spokes each, eight rivets and the welded wheel rim.

The cast-iron hub calls for five or more operationsmaking the core, molding, pouring, tumbling, and spruing on the emery-wheel. The coring length and outside diameters

are all close to uniformity, and the hub and side flanges and spokes make a firmly united structure after they are assembled in the press, before riveting (as shown in Figs. 208 and 209), as the eyes of the hub-flanges are forced down hard on the outside of the hub.

For the tire, seven operations are required-to cut it off from the bar, straighten, punch with a hole for each spoke end, six or eight as may be, and two rivet-holes for the weld

FIG. 198.-Small rim-bending rolls.

rivet, which insures the correct tire diameter; insert the weldrivet, heat and weld, and finally form and trim on a round iron-block. None of the operations on the wheelbarrow tire are shown, as larger wheel tires were in work the day the pictures were taken.

The tires are cut off in the press, and all the holes are punched at once-square holes for the spoke ends, and a round end for the welding-rivet. Fig. 198 shows the little Moline tire-bender, three rolls open at the right hand, one adjustable. The larger tires are bent in a larger Moline machine, Fig. 199, having the adjustable roll carried on a

rectangular gibbed slide at the left. The company make wheels up to 54 inches diameter, with rims 6 inches wide, and fit them with two sets of V-section spokes, spread at the base, and extremely substantial in construction, to carry as much as 3,000 pounds load per wheel-an entirely different affair from this simple and cheap wheelbarrow wheel.

The rims are heated for welding in the natural-gas fire, shown in Fig. 200. This is a fire-brick pit, not very wide,

FIG. 199. Larger rim-bending rolls.

having two loose fire-brick sliding covers, raised up on bricks 2 or 3 inches above the hearth surface. The natural-gas pipe is at the left, globe valve regulation, and the tin air-pipe takes the gas at the top bend, above the flat air-regulating slide, fixed in position with the thin wooden wedge lying on top of the slide. The flame was shut off for the camera exposure, but the pit was yet red hot. The two fire-brick covers are made each of two bricks, pierced together with clamp-plates

and bolts, all as clearly shown. When the tires are to be put in the top bricks are shoved along endwise, and shoved back again to cover the tops of the heating-ends, and the fire is extremely rapid in action.

The superintendent was very loath to permit a picture of this simple, cheap, convenient, and most effective hearth to go out, because it was not more elaborated. Like everything else in this shop, this fire was working all day every day all right,

costing next to nothing in fuel, extremely good in every way, which did not at all hinder the superintendent from wishing it not to be shown. I, on the other hand, regarded the fire as a model construction, very difficult to cheapen or improve. The rims are welded on horn-frame "Justice" spring-hammer, as shown in Fig. 201. The top spring and cranks are covered by a large sheet-metal case, as the hammer works fast. The hammer works only a few seconds on each weld, and the