Basic Hand Tools for the aircraft newcomers

Wrench Sizes

• Customary tool sizes are given in fractions of an inch. The measurement is the width of the jaw opening. As shown here, these sizes are not the same as bolt sizes.

• Metric wrench sizes are given in millimeters. The measurement is the wide of the jaw opening. The wrench size is not the same as the bolt size.

Brain Teaser!

• If 1 inch equals 25.4 mm (millimeters), would a 25mm (millimeter) wrench fit a 1 inch bolt?
• If your answer is Yes, would the 25mm (millimeter) wrench fit snug or loose?
• If you answer is No, explain why not.

• Open-End Wrenches- An open-end wrench has an open jaw on both ends. Each end is a different size and set at an angle.
• Box-end Wrenches- Box-end wrenches are completely closed on both ends. They fully surround and grip the head of the bolt or nut.
• Combination Wrenches- A combination wrench has a box-end jaw on one end and an open end on the other. Both ends are usually the same size.
• Line Wrenches- A line wrench, also called a tubing wrench or flare nut wrench, is a box-end wrench with a small opening or split in the jaw. The opening allows the wrench to be slipped over fuel lines, brake lines or power steering line and onto the fitting nut.

Practice

• Name four rules for wrenches
• Never hammer on a wrench
• Never use “Cheater bars”
• Select the right size wrench for the job
• When possible pull on the wrench. Use the palm of your hand if you have to push on the wrench

Socket Wrenches

• A socket is a cylinder-shaped, box-end tool for removing or installing bolts and nuts. One end fits over the fastener. The other end has a square hole that fits on a handle used for turning.

• Different socket types. Note both standard and deep-well sockets are shown.