Machine Shop

For the fabrication of fixed spans not many machine tools are required, the turning of pins, the planing of main members, shoes, and base plates, and the boring and drilling of holes being about the only machine operations required. If, however, movable spans are to be manufactured, a small machine shop will effect an economy of operation. Such a machine shop should be equipped with the following tools:

Boring Mill,

Grinding Machine,

Lathe,

Screw Cutter,

Planing Machine,

Slotting Machine.

Foundry

It is probable that an iron or steel foundry cannot be added to the equipment of the fabricating plant with economy, unless there is a market for general commercial work; because there are not enough castings required in bridgework to keep a foundry busy more than a very small portion of the time.

Blacksmith Shop

A Blacksmith Shop should be installed with hammers, presses, heating furnaces, etc. If the Shop is one of large capacity, there should be added a rivet-and-bolt-making plant with the necessary heating furnaces, continuous rivet-making machines, bolt machines, screw-cutting machines, and bins for the storage of rivets and bolts.

Shop Assembling

Bridge specifications in many cases provide that the members of riveted trusses shall be assembled at the shop, that the field holes shall be reamed while the trusses are so assembled, and that the members shall be match-marked before they are taken apart. This ensures the proper matching of the holes when the work is subsequently erected. The shop, therefore, should have the necessary space and equipment for assembling such trusses. Generally, it is economical rather than the reverse to do such assembling and reaming; but, if there be a large number of duplicate spans, it is uneconomical. In such a case the field connections should be reamed to iron templets, so that the members will be interchangeable. The work can be done much more quickly in this way; and, if it be carefully performed, the results will always be satisfactory. If desired, one or two of the trusses can be assembled before any of them are shipped, in order to check the accuracy of the work.