=Broach.= A toothed tool for cutting the walls of a hole.

=Broaching-press.= A machine that forces a broach to its cut.

=Bunter-dog.= A work-gripping device for a planing machine, and consisting of a piece having a hook end to engage in the T-slot of the table, and a set-screw to bind the work.

=b.u.t.t-joint.= A riveted joint in which the ends of the plate abut fair, one against the other.

=b.u.t.t-strap.= A strip or band of iron employed to hold the joint together in a b.u.t.t-joint.

=b.u.t.t-weld.= A weld in which the end of one piece merely abuts against the other when the two pieces are put together to weld.

=Buzz-planer.= A wood-planing machine in which the work is fed by hand.

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=Calender-roll.= A roll for calendering paper.

=Caliper-gauge.= A gauge in the form of a solid caliper.

=Calipers.= A hinged tool for measuring work.

=Cam.= A revolving disc whose actuating surface is not a true circle.

=Cam-motor.= A cam together with the rod it actuates.

=Cap.= The plate or upper part of a bearing that holds the top half of the box or bra.s.ses in place.

=Cape-chisel.= A narrow machinist's chisel.

=Caps.= The backward curves on the points of file teeth.

=Cap-screw.= A screw with a collar and a square head.

=Carrier.= A device for driving lathe work.

=Case hardening.= A process of hardening the surface of wrought iron, the hardening usually extending about 1/32 inch in depth.

=Cat-head.= A sleeve fastened by set-screws to slender lathe work and running in a bearing so as to steady the work.

=Caulking-tool.= A tool used for caulking riveted joints and in making rust-joints.

=Centre-bit.= A bit having a triangular conical point with its cutting edge on one-half of the end and a spur on the other half.

=Centre-punch.= A tool having a coned point for marking the centres to work.

=Chamfer.= A facet that removes the corner of a right angle.

=Change-gears= _or_ =change-wheels.= The gear wheels employed to change the revolutions of a lead screw or feed motion.

=Chaser.= A toothed tool for cutting threads by hand in a lathe.

=Check.= A crack.

=Check nut.= A second nut screwed against the first to check it from slackening back.

=Chip-break.= A piece that rests upon the work of a wood-working machine and prevents the cutter from splitting out the wood as the cut leaves the surface.

=Chipping-hammer.= A machinist's hand hammer.

=Chips.= 1. The cutting from a metal cutting machine tool. 2. The thick cuttings from a wedge-shaped wood-working tool, as from an axe or adz.

=Chisel.= A wedge-shaped tool.

=Chisel-tooth saw.= A saw having inserted teeth with a maximum of front rake.

=Chop= _or_ =hammer-sink.= A mark left on a plate by a sawmaker's or plate straightener's hammer.

=Chord-pitch.= The pitch of gear wheel teeth measured in a straight line.

=Chuck.= A work-holding or tool-holding device.

=Chucked.= Held in a chuck.

=Chucking-lathe.= A lathe having a large face plate for chucking purposes, and usually a short bed.

=Chuck-plate.= A large face plate on which work may be chucked.

=Circular saw.= A saw having its teeth arranged around its circ.u.mference.

=Clamp.= A device for fastening or holding work together or to some other part.

=Clearance.= 1. The amount to which one piece clears or escapes another.

2. On a lathe tool, clearance is the amount to which the back face of the tool escapes the metal it is cutting.

=Clements driver.= A device for driving work in a lathe, and that places an equal strain on each end of the lathe dog or carrier.

=Clutch.= A device for engaging or disengaging so as to cause the motion of one piece to be communicated to another, or to stop such communication.

=c.o.c.k.= A device for opening or closing the bore of a pipe.

=Cog.= A wooden tooth for a gear wheel.

=Collapsing-taps.= A tap that is so formed that its teeth close inwards when the thread is cut so that the tap can be withdrawn without winding it backwards.

=Collar.= 1. A disc-shaped enlargement on a cylindrical piece. 2. A hollow cylindrical piece containing a set screw, to prevent a shaft from end motion.

=Collet.= A casing for holding tools or drawers in position.