Practical Carriage Building
Compiled by M.T. Richardson, Vol.1. 1891
What I know about Wagon Wheel Making
I fully believe that a first-class wheel can be produced only by the most judicious exercise of mechanical skill. It is the combination of seemingly simple and trifling things which makes all the difference between a good and a bad wheel. But nevertheless it is a well known fact that many poor wheels are made. I will go further and say that a good wheel cannot be made unless the timber of which it is con¬structed is first-class. No amount of good workmanship can make amends for the lack of good material. It is no exag¬geration to say that there are many more poor wheels than good ones. Most wagon smiths know that all wheelwrights are not masters of their trade. Of what good is a vehicle if its wheels are defective? There is a well-known and trite saying, "No wheels no wagon."
My idea of what a good wheel should be is this: First, the timber of which the wheel is built must be first-class and well seasoned. No other kind would pass muster with me. It is of as much importance that the timber should be well seasoned as that it should be good. No matter how good a workman may be, he never can make a good wheel out of unseasoned timber. If the wheels—say a farm wagon—are to be well made, the forward wheels should be straight across the face. What I mean is, that if a straight edge is held across the face of the wheel, it should touch the base of the spokes, and also both sides of the rim. That is what is called a wheel straight on its face, without any dish. For the hind wheels I think barely one-eighth of an inch dish is enough, before the tire is set. If the felloes of the wheels set well down on the shoulders of the spokes, and the felloes—if cut ones—are close jointed only between two of them, and only about an eighth of an inch there, the wheel, if the tire is set as it should be, ought to have about one-eighth of an inch dish in the forward wheel and a quarter of an inch in the hind one. I think that is plenty of draft for the first time. Much depends upon the wheels. How much draft must be given, only experience can determine; but I claim half an inch draft for the forward wheels and three-eighths for hind ones, when the tire is cold, is enough. The experi¬enced smith knows how much to allow without cooling the tire. If, when he 'runs' the tire, the weld is at a white heat, he allows less; if at a dull red, then a little more. Before the smith sets the tire, he ought to see that one of the spokes stands above the rim, for if he does not attend to this, he is sure to get more dish in the wheel than he expected. Never put the weld of a tire opposite the open joint of a wheel, but always in the middle of the felloe. I think the notion is quite prevalent among wheel makers and users of wheels that plenty of dish fills the all-important condition of safety. Now, I think just enough dish to pre¬vent the possibility of the spokes turning back from their angular position to a vertical one, is all that is necessary; and the better the wheel is constructed, the less liability there is of it turning back or inside out. I think some wheels turn back because they were not originally properly constructed.
For my part I think no forward wheel ought to have more than five-eighths of an inch dish, and there should be no more than three-quarters of an inch in the hind wheel. After the wheels get that amount of dish in them, the tire cannot be made tight. You simply pull the spokes over, and as soon as the tension is out of them, the tire will come loose again. And it is also very certain that, after the dish is reached, the tire will dish the wheel very much more than before, for it is a well known fact that when the spokes are once bent or kinked, they never can be made straight again. Undoubtedly many wheels are made too straight; that is to say, they are about the same at the back as they are in front. As a rule you never can put any dish in such wheels, and unless the tire is always kept tight, the wheel will always turn back; and if the vehicle is heavily loaded and the wheels drop into a deep rut, they often break by being turned inside out, or rather inside in. I have seen many such wheels.
Some of our most prominent manufacturers of carriages and Wagons practice the system of gouging or cutting out the ends of the spoke tenons below the surface of the rim, in order that the tire, when shrunk on, may draw the rim well up against the shoulder of the spokes, which, if the spokes were not cut out, would tend to kink or bend them. This is not so practical a theory as it may at first seem. It should be borne in mind that because the tire has dished a wheel considerably, it does not follow that the joints and shoulders arc well drawn together. Neither does it prove that the tire is on very tight, for as soon as the spokes lose their tension by being drawn over by the tire, the latter may be found very loose on the rim.