Servicing
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the Steam Wagon
THE steam wagon is usually well looked after because the man in charge of it is, in most cases, expe.ienced by reason of years of training, but this type of vehicle has to undertake extremely arduous duty. In working in quarries and sandpits, and travelling over irregular ground which cause considerable strain and would seriously distort frames if they were not very strongly made, the steamer is stressed to the utmost of its capacity.
The steam wagon, by its very nature, goes on uncomplainingly, and if it be not examined periodically the possibility is that it will give serious trouble quite suddenly.
A round of the works of G. Scammell and Nephew. Ltd., the .scam
wagon engineering and bodybuilding concern of Spitalfields, Loudon, E.1, is likely to surprise the average haulage contractor who does not, perhaps, appreciate the highly specialized character of steam engineering.
The Inspection of Boilers.
Boiler work can only be placed in the hands of most reputable engineers, because actual danger to drivers and to the public may result from any • oversight or carelessness in connection with it. The 'Factory Acts which provide for the periodical inspection by certificated engineers of factory boilers do not apply to steam wagons, a fact which emphasizes all the more the need for operators to employ specialists to look after their steam vehicles.
The method of hammer-sounding the ends of firebox stays—to give an example—may reveal broken ones, but gives no indication as to where the stays are wasted. Stays that are inaccessible should be suspected.
An interesting side of the Setimmell concern's maintenance work is that in connection with valve guides. In many cases these are integral parts of the cylinder castings, and when they become worn it is necessary to have them bored out to take valve stems of larger diameter—a process which cannot be repeated many times. To avoid the expense of replacing the whole casting the external projecting portion of the guide is cut off, leaving a machined face. -A new phosphor-bronze guide is then fitted, this comprising an inner member, flanged at one end and screwed on the outside at the other end, and an outer member which is screwed over it. The inner member is inserted so that the flange is against the inside face of the old guide and it is held quite rigidly by the outer member.
To avoid the drilling of fireboxes with larger holes than are necessary, when overhauling is in progress, a " stepped " pattern of stay is employed by this concern. The advantage is emphasized when the thread on the outer plate requires to be re-cut, this resulting in the hole being larger than
previously. Ifstay of the same section throughot its length be fitted, the firebox would be weakened.
The above two instances are quoted simply to give an idea of the ingenuity
that can be brought to bear in the maintenance of steam wagons. We noticed at the works the method employed for strengthening and resetting laminated road springs. Additional spring leaves are inserted between the original ones, the lengths being carefully graduated so that the finished spring is of normal appearance. The bosses are then altered to fit the longer centre bolts.
Strengthening Chassis Frames.
In the matter of chassis frames, careful inspection and strengthening are frequently called for, particularly at points where cross-members are riveted to the main longitudinal members. At the Scammell works an oxy-acetylene frame is employed to cut away the extreme ends of the cross-members sufficiently to admit the insertion of steel strengthening plates. These are welded to the main and cross-members. It is a particularly clever method of dealing with a constantly recurring trouble, and a good point is that the rivets holding the cross-members to the main frame are not disturbed if sound.
Of course, G. Scammell and Nephew, Ltd., has, for close on a century, maintained a reputation in the manufacture of all kinds of bodywork for goods vehicles, so that, while chassis repair is being proceeded with, bodies can be renovated or re-built and the owner or operator is able to take delivery of a machine which has been thoroughly and efficiently overhauled in every respect.