ASVAB Shop Information Practice Test 958861

Questions 5
Topics Calipers, Clamps, Fasteners, Pincers, Ratchets

Study Guide

Calipers

Calipers are similar to micrometers in shape but instead of measuring distances, calipers are used to transfer distances between objects. An outside caliper is used to transfer outside dimensions while an inside caliper is used to transfer inside distances. A vernier caliper is an extremely precise caliper (down to \({1 \over 1000}\) inch) that allows measuring / transferring either inside or outside dimensions.

Clamps

A clamp applies pressure to prevent two objects from moving relative to each other, for example, to keep to pieces of wood together while the glue between the dries. A clamp is commonly made of metal and shaped like the letter C with a perpendicular flat-edged plate providing variable pressure between it and the top of the C as a screw to which it is attached is tightened and released.

Fasteners

Wrenches are used with threaded fasteners like bolts and nuts. A bolt has external threads while a nut has internal threads and this thread pattern combination allows them to lock together and act as fasteners. Nuts come in a variety of configurations including wing nuts which provide appendages that allow tightening and loosening by hand, slotted nuts that use a cotter pin to lock the nut in place and prevent it from loosening, and lock nuts that also prevent loosening via nylon in their threads. Threads are identified by pitch which is the number of threads per inch.

Pincers

Pincers provide a mechanical advantage that's used to cut, pinch or pull an object. The force applied to pincers is concentrated to a point or to an edge of the tool which allows pincers to be brought very close to a surface. Pincers are typically used for removing objects from a material to which they've previously been applied, for example, to pull nails from wood.

Ratchets

A ratchet (or socket wrench) is a wrench that applies torque in only one direction with a handle that can be moved back and forth without losing contact with the fastener. A ratchet uses variable attachments called sockets which come in a variety of drive sizes based on the size of the opening that attaches to the ratchet. Sockets with the same drive size will vary in the shape (six-point, twelve-point) and size of the nut opening that attaches to the fastener being tightened or loosened. Smaller point sized sockets are stronger and can apply greater torque while larger point sizes allow easier alignment.