ASVAB Mechanical and Shop Review Flashcards

A comprehensive set of vocabulary flashcards covering mechanical comprehension and shop tools from the ASVAB review notes, including rivets, engine systems, levers, and simple machines.

Standard Rivet

A fastening device used extensively in aircraft that must be driven using a bucking bar and is classified by length, diameter, head shape, and size.

Pop Rivet

A type of rivet with self-heading capability used for blind fastening when there is limited or no access to the reverse side of the work.

Rivet Length Formula

The length of a rivet should equal the sum of the thickness of the metal plus 1\frac{1}{2} times the diameter of the rivet.

Fuel-injection system

An engine system that uses injectors to spray fuel mixture into the combustion chamber, eliminating the necessity for a carburetor.

Piston rings

Engine parts that coat cylinders with oil; when worn, they allow oil to enter the combustion chamber to be burned.

Rotor

A component that turns inside the distributor to distribute electricity to the spark plugs at the exact time required for combustion.

Cylinder head torquing sequence

The specific order of tightening used to prevent distorting or warping the head and ensuring proper heat dissipation.

Compass saw

A saw used mainly to cut circular or other nonrectangular, odd-shaped holes in wood.

Tin shears

Tools used for cutting sheet metal to prevent the metal from becoming distorted.

Lathe

A machine used to make objects of one solid piece with usually rounded shapes, such as table legs and baseball bats.

Hole saw

A tool that uses a drill bit-like instrument to start a hole and a rounded saw blade to cut the actual hole.

Lever

The simplest machine, consisting of a rigid part that pivots about a point called the fulcrum.

Fulcrum (F)

The pivotal or fixed point about which a lever rotates.

Effort (E)

The force applied to a machine to overcome a resistance.

Resistance (R)

The weight or force that acts as the load to be overcome by a machine.

First-Class Lever

A lever where the fulcrum is located between the effort and the resistance; examples include seesaws, crowbars, and pliers.

Second-Class Lever

A lever where the fulcrum is at one end and the effort is applied at the other, with the resistance located between them.

Third-Class Lever

A lever where the fulcrum is at one end and the resistance is at the other, with the effort applied at a point between them to increase speed.

Mechanical Advantage (M.A.)

The ratio that indicates how much a machine magnifies applied force, calculated as $M.A. = \frac{R}{E}$ or $M.A. = \frac{A}{a}$ ($\text{Effort Arm} / \text{Resistance Arm}$).

Block and Tackle

A system of blocks (pulleys) and ropes (falls) rigged to make work easier by changing direction or magnifying force.

Fixed Block

A single block lashed to a fixed object that changes the direction of pull but has a mechanical advantage of $1$.

Runner

A single movable block-and-fall arrangement where the fall is doubled, providing a mechanical advantage of $2$.

Gun-tackle purchase

An arrangement of two single blocks (one fixed and one movable) used to change the direction of pull while maintaining a mechanical advantage of $2$.

Luff tackle

A tackle consisting of a double block and a single block that provides a mechanical advantage of $3$.

Wheel and Axle

A simple machine consisting of a wheel or crank rigidly attached to an axle that turns with it, used to multiply force or speed.

Torque

Also known as moment of force, it is the result of a force acting on a lever arm tending to cause rotation about a center point.

Inclined Plane

A simple machine, such as a ramp, that permits overcoming a large resistance by applying a small force through a longer distance.

Wedge

A special application of the inclined plane consisting of two inclined planes set base to base, used for cutting or splitting material.

Screw

A simple machine that is effectively an inclined plane wrapped around a cylinder in a spiral form.

Pitch

The distance between identical points on successive threads of a screw, measured along the length of the screw.

Jackscrew Mechanical Advantage Formula

The theoretical advantage calculated as $M.A. = \frac{2 \times \text{π} \times r}{p}$, where $r$ is the handle length and $p$ is the pitch.

Micrometer

A device used for accurate small measurements (thousandths of an inch) using screw threads cut at $40$ threads to the inch.

Gears

Machines used to change direction of motion, change speed, or magnify force with a positive drive that prevents slipping.

Spur gears

Gears used to transmit motion between two shafts that are parallel but not in the same straight line.