Hand Hole

Opening made in a ve el which is to withstand pre ure, so that an arm or hand may be inserted for inspection or repair. When large enough to allow a man's hips 676 shape, because this causes least waste of metal, and it is po ible to insert the elliptical lid from the outside after the ve el is made. The lid is put on from inside, with a gasket between the plate and the lid, and the joint is made tight by drawing up the lid by means of a nut upon a bolt or stud, the nut bearing upon a dog or bridge which spans the opening outside, and through which the stud pa es from below. Hand-holes are put in the water-legs and other non-permeable places in boilers. Man-holes require a re-enforcement of the plate at the edge, and are more usually put on flat parts of the sheet. Man-holes are also put in large cylinders, condensers, and other similar ve els.