10. (Mach.)
Defn: A piece of brass, lead, or other soft metal, used to hold a cutting or polishing powder in cutting glass, gems, and the like, or in polishing cutlery, etc. It is usually in the form of wheel or disk, which revolves on a vertical axis. Lap joint, a joint made by one layer, part, or piece, overlapping another, as in the scarfing of timbers. — Lap weld, a lap joint made by welding together overlapping edges or ends. — Inside lap (Steam Engine), lap of the valve with respect to the exhaust port. — Outside lap, lap with respect to the admission, or steam, port.
LAP
Lap, v. t. [imp. & p. p. Lapped (; p. pr. & vb. n. Lapping.]
1. To rest or recline in a lap, or as in a lap. To lap his head on lady's breast. Praed.
2. To cut or polish with a lap, as glass, gems, cutlery, etc. See 1st Lap, 10.
LAP Lap, v. t. Etym: [OE. lappen to fold (see Lap, n.); cf. also OE. wlappen, perh. another form of wrappen, E, wrap.]
1. To fold; to bend and lay over or on something; as, to lap a piece of cloth.
2. To wrap or wind around something. About the paper . . . I lapped several times a slender thread of very black silk. Sir I. Newton.
3. To infold; to hold as in one's lap; to cherish. Her garment spreads, and laps him in the folds. Dryden.
4. To lay or place over anything so as to partly or wholly cover it; as, to lap one shingle over another; to lay together one partly over another; as, to lap weather-boards; also, to be partly over, or by the side of (something); as, the hinder boat lapped the foremost one.