The work of building a boiler is partly that of shaping flat steel plates into cylindrical and flanged forms, and partly that of assembling with these forms certain products of other shops, as tubes, corrugated furnaces, stay bolts, etc. The whole assemblage composing the boiler proper is fastened together by rivets, screwed stays, and expanded tube ends; and when ready for use the boiler is supplied with such fixtures as the uptake and the smoke pipe, which are built in the boiler shop, and with such fittings as steam gage, stop valve, safety valve, etc., furnished by other shops.