tapered punch. A hand-held punch that is tapered from its full shank size to a smaller diameter at its end. Tapered punches are used to start bolts, pins, or rivets from their holes.

tapered roller bearings. A form of antifriction bearing that uses hardened steel rollers between hardened and polished, cone-shaped steel races. Tapered roller bearings take thrust loads as well as radial loads.
tapered-shank drill. A form of twist drill normally used in a large drill press or a lathe. The shank of the drill is tapered and is held in the spindle by friction. The drill is removed by forcing it out with a tapered wedge driven through an opening in the spindle.
taper tap (thread-cutting tool). A type of thread-cutting tap used to start the threads in a hole. The first six or seven threads on the end of the tap are ground in the form of a taper so the tap can easily enter the hole.
tap extractor. A tool used to remove a broken tap from a hole. Taps are made of very hard and brittle steel and they can be broken off in the hole being tapped. The tap extractor has a series of fingers that can be stuck down into the hole through the flutes in the tap. When the tap extractor is turned with a wrench, the fingers turn the tap and screw it out of the hole.
tapped resistor (electrical component). A type of wire-wound resistor with connections made to the resistance wire at points between its ends. The connection to the resistance wire is permanent in some tapped resistors, but other resistors have a section of the wire left bare. A clamp can be moved to a point where it contacts the wire at the correct point to furnish the desired resistance. The clamp is then tightened.

tappet (reciprocating engine component). The component in the valve train of a reciprocating engine that rides on the lobes of the cam shaft or cam ring and pushes against the pushrod. A tappet is called a cam follower. In many reciprocating engines, the tappet incorporates a hydraulic valve lifter that automatically adjusts for the changes in the length of the valve train mechanism caused by temperature changes.
tare weight (aircraft weight and balance). The weight of all the chocks and other items used to secure an aircraft on the scales for weighing. The tare weight must be subtracted from the scale reading to find the weight of the aircraft.
target (radar technology). Any of the many objects detected by radar.
target blade (helicopter rotor blade). The blade of a helicopter rotor identified as the reference blade when the rotor is being electronically checked for balance.
tarmac. The British name for a hard-surfaced area on an airport where aircraft are tied down and serviced. The term tarmac comes from tarmacadam, a mixture of tar and crushed stone, often used as the surfacing material.
tarnish. A dull surface which forms on some types of metal when oxygen in the air changes some of the metal into its oxides. Polished aluminum, for example, tarnishes, or turns dull, when aluminum oxide forms on its surface.