A Hole

An equal-sided or circular opening which extends entirely through an object from one of its surfaces to some other surface. If the opening is not circular, square, octagonal, or of similar form, but oblong, it is a slot. When a hole or slot is covered or closed at one of the entrances, it becomes a recess; and when closed at both entrances, it is a cavity.

A Holder Or Handle

A projecting piece of metal which is cast solid with the work to afford a means of fixing it during planing, turning, and other operations. A holder may be also forged solid with a rod, bar, or key that requires planing, the holder being cut off after the key is fitted.

An Index

A steel instrument which is finely pointed and polished to indicate a point, and denote minutes and seconds of angles and arcs.

To Jam

To fasten two nuts together on one bolt. Of two nuts thus fixed, the one put on last is termed a lock nut; and the greater the thickness of this nut, the greater is the friction surface of the screw; consequently the thicker the lock nut, the less is its liability to rotate on the bolt, and separate from the other nut.

A Lid

The lid of a slide-jacket is bolted to the flange of the jacket. The lid of a valve-box is bolted to the box after the valve or valves are put within.

A Line

A line in a piece of work, is any stated distance into it, through the work, or across one side of the work. A line on one side of a lever or rod is denoted by a scratch or indentation.

To Line

To mark a hne or several lines into various sides of a piece of work, to discover centres, and to enable men to work to the lines.

A Machine

An instrument consisting of several moving parts. Any instrument which contains a lever and axle; or which contains several levers without an axle.

To Mark A Line

To mark a line upon a lever, is to draw a steel point along some part of the lever and plough up a portion of the lever, or plough a furrow into the layer of whiting that may be on the surface.

A Neck

The neck of a bar is an intermediate part between two thick portions. The neck of a bearing, is the portion between two shoulders of the bearing; therefore if a bearing has two shoulders, it has one neck; and a thrust bearing having ten shoulders, has five necks.

To Oscillate

To move gently to and fro, and traverse arcs while moving. To swing backwards and forwards a rod or rope which is sustained at one end. To swing a cylinder on its trunnions.

A Pinion

In machinery, a pinion is a relative term to denote the smaller of two cogwheels that work together, whether the pinion drives the wheel, or the wheel drives the pinion.

A Pulley

A relative name to distinguish between two wheels or drums that are connected with a driving band ; the driving wheel being that which gives motion to the band, and the pulley being that which is pulled and rotated by the band.

To Scribe - To write with a steel instrument, named a scriber. To mark a line with chalk or with slate-pencil upon a piece of work, or upon a table. To scribe a line, signifies merely to write the line, without regarding its position to any other line.

A Scriber

A scriber for marking diagrams on tables or plattens, is a piece of steel wire which is hardened and pointed at one end, to give it a capability of cutting the surfaces of iron, steel, and other metals. Scribers are of various lengths, according to whether they are required to be held in one hand while scribing, or fixed in legs of compasses and other scribing instruments.

A Shoulder

The shoulders of bolt-heads, are the surfaces that press against the work to be bolted together. The shoulders of an axle-bearing, are the surfaces that sustain any strains which are imparted to the axle in the direction of its length.

A Slit

A cut. A split. An opening or space extending through a piece of work, if the opening is made by means of a hand-chisel, chopper, steam-hammer chisel, or similar tool.

A Slot

A regularly formed oblong opening, which extends entirely through a plate, rod, or bar; consequently, a slot resembles another hole in being closed except at two places, which are the entrances or mouths of the slot. Slots may be oval, rectangular, serpentine, or arched; and may be made by punching and drifting; also by drilling-machines and slotting-machines.

A Socket

A short tube intended to contain one end of a smaller tube, or to contain one end of a shaft, axle, rod, or bar.

A Stroke

The stroke of a slide-valve is the length of the path along which the valve moves. The stroke of a piston is the length of its travel or path.

To Temper

To moderate. To mix cements. To soften a tool to the proper degree of hardness, after the tool is hardened by cooling it in water, or is hardened by some other means.

A Vibratory Strain

When a rod or bar of steel is quivered by hammering, or other means, the fibres are either bent or broken; if the fibres of the bar are short in the direction of the bar's length, the quivering drags some of the particles across those in contact, and this cross motion from one side of the bar to the opposite breaks some of the fibres; and if the quivering is continued, the bar will be divided at the place where the breakage of the fibres commenced; but if the fibres are of considerable length, and parallel to the length of the bar, the quivering merely bends it, and must be continued a long time before it is broken.

The general significations given with the foregoing phrases are sufficient for many of the processes in the "Mechanician;" but, through the custom of making one word signify several different things, it will be necessary, as we proceed, to specially define ambiguous terms.