CASA B-07b Workshop Practices and Hand Tools

Vocabulary practice flashcards covering aviation workshop practices, tool control, hand tools, machining, abrasives, and torque calculation formulas based on CASA B-07b notes.

Workmanship

The degree of skill with which a job or product is completed, including quality, attitude, duty of care to self, others, and equipment, and working to a standard.

Standard

An agreed way of doing something, categorized into private, national, and international (ISO) types.

Tool Control Primary Responsibility

The primary responsibility for tool control sits with the tool user, not management.

Shadow Board

A storage board that visually shows where a tool belongs and whether it is missing.

Tolerance

The permitted variation in a dimension, often shown as a $\pm$ value or the total difference between upper and lower limits. Common-fraction dimensions on aircraft drawings normally assume $\pm \frac{1}{64}\,in.$

Allowance

The prescribed difference between maximum material limits of mating parts, resulting in positive allowance (clearance) when a bolt is smaller than the hole or negative allowance (interference) when a bolt is larger than the hole.

Prick Punch

A punch used to transfer dimensions and locations to sheet metal. It should never be used to drive a pin or rivet.

Centre Punch

A punch used to create a deeper witness mark that helps a drill start accurately.

Starter Drift

A drift punch used specifically to jar taper or parallel pins loose.

Pin Punch

A punch used to drive already loosened pins, dowels, and rivets out.

File Grades

Grades of files ordered from roughest to smoothest: Rough, Middle, Bastard (for fast material removal), Second Cut (smoother/slower), Smooth (for finishing), and Dead Smooth.

Safe Edge File

A file with an edge that has no teeth, designed to protect an adjacent finished surface while filing.

Aviation Snips Color Code

Color coding scheme for sheet metal snips: Yellow cuts straight, Green cuts right, and Red cuts left.

Hacksaw Blade Selection Rule

Guideline specifying coarse pitch for soft/thick metal ($18\text{ TPI}$) and fine pitch for hard metal, thin material, or tubing ($24\text{ TPI}$ or $32\text{ TPI}$), maintaining at least $3$ teeth in contact with the work.

Standard Drill Point Angle

The standard included point angle for drills, which is $118^\circ$. Very soft materials may use about $90^\circ$, while hard materials may require up to $150^\circ$.

Countersink vs Dimple

Countersinking removes metal when sheet material is thick enough, whereas dimpling forms or presses the sheet when skin is too thin to countersink.

Reamer

A tool that enlarges an existing undersized hole to improve accuracy, finish, and concentricity. It follows the existing hole and does not correct its position or direction.

Tap Order

The sequence for cutting internal threads: Taper (starts alignment), Intermediate (deepens thread), and Bottoming/Plug (finishes blind/deep holes). Note that BA tap sets have no intermediate tap.

Die Nut

A tool used exclusively to restore or ease a damaged thread, not to cut a new thread.

Screw Extractor

A tapered extractor with a left-hand spiral used to remove broken fasteners by turning anti-clockwise for right-hand threads and clockwise for left-hand threads.

Ring Test

An inspection method for grinding wheels before mounting where a sound wheel produces a clear metallic ring and a cracked wheel yields a dull or dead sound.

Aluminium Oxide (Alundum)

An abrasive material used for grinding steels and tough high-tensile materials.

Silicon Carbide (Crystolon)

An abrasive material used for grinding stone, ceramics, and non-ferrous materials.

Grinding Loading

A defect where removed material clogs spaces between abrasive grains, usually caused by using the wrong wheel for soft/ductile materials.

Grinding Glazing

A defect where abrasive grains become blunt but the bond is too hard to release them, requiring a softer bond wheel.

Dressing vs Truing

Dressing cleans the cutting face to expose fresh abrasive after loading or glazing; Truing makes an out-of-round or grooved wheel square and concentric.

Torque Formula

$\text{Torque} = \text{Force} \times \text{Lever Length}$, which produces clamping preload in a fastener.

Torque Calibration Validity

The typical validity period for a calibrated torque wrench, stated as $6\text{ months}$.

Over-Torqued Fastener Procedure

Procedure requiring an over-torqued fastener to be removed, rendered unserviceable, and scrapped (along with both bolt and nut if applicable) rather than backed off and re-torqued.

Normal Re-Torquing Procedure

Procedure specifying that when normal re-torquing is required, the nut must be backed off one full turn before re-tightening to the specified torque.

Progressive and Pattern Torquing

Progressive torquing tightens fasteners in stages to prevent uneven loading; Pattern torquing follows a specific tightening sequence to prevent structural distortion.

Torque Multiplier

A device used when required torque exceeds practical wrench limits, typically featuring gear ratios from $3:1$ to $11:1$.

Torque Extension Formula

Formula used to calculate wrench setting when using an extension: $\text{Scale Reading} = \frac{\text{Specified Torque} \times L}{L + X}$, where $L$ is wrench length and $X$ is extension length.

Torque Wrench First Quarter Trap

The principle that the first quarter ($\frac{1}{4}$) of a torque wrench scale is insufficiently precise for aviation use.