2.3 Tools of the Trade: Hand and Power Tools
Key Takeaways
- Module 32102, Tools of the Trade, is one of the four modules behind the 14-item IMM Fundamentals domain.
- A box-end or socket wrench grips all six corners of a fastener; an open-end or adjustable wrench grips two flats and is the usual cause of rounded corners.
- Striking a hardened tool such as a file, a socket, or a hardened chisel head with a steel hammer can shatter it; use only tools designed to be struck.
- A torque wrench is a measuring instrument and should not be used as a breaker bar, and click-type wrenches are stored backed off to their lowest setting.
- Portable electric tools must be grounded, double insulated, or supplied through ground-fault circuit interrupter protection.
Why tool items are easy points that candidates still lose
Module 32102, Tools of the Trade, feeds the 14-item Fundamentals domain. Assessment items in this area test selection and misuse, not brand names: which wrench to reach for, which tool may be struck, what a grinder guard clearance must be. Working mechanics often lose these items because they answer from shop habit rather than from the standard.
Wrenches and sockets
| Tool | Contact with the fastener | Best use | Failure mode when misused |
|---|---|---|---|
| Box-end wrench | All six corners (12-point or 6-point) | Breaking loose and final tightening | 12-point on a badly rusted nut can still slip |
| Open-end wrench | Two flats | Quick turns in tight quarters, line work | Spreads under load and rounds corners |
| Combination wrench | Both of the above | General purpose | Using the open end for breakaway torque |
| Socket, 6-point | All six corners with maximum wall contact | Impact and high-torque work | Using a chrome hand socket on an impact gun |
| Socket, 12-point | Six corners, thinner walls | Limited swing arcs, 12-point fasteners | Splitting under impact loads |
| Adjustable wrench | Two flats, one jaw movable | Odd sizes, jam nuts | Jaw backlash rounds the fastener |
| Pipe wrench | Toothed jaws bite round stock | Pipe and round bar only | Never on nuts, valve bodies, or plated fittings |
| Strap or chain wrench | Friction around the circumference | Plated or finished pipe and filters | Slipping on oily surfaces |
The rule to remember: always pull a wrench toward you rather than pushing, and pull with the palm open where the fastener may break loose suddenly. On an adjustable wrench, position the handle so the force is taken by the fixed jaw, not the adjustable one.
Torque wrenches are measuring instruments. Do not use one to break a fastener loose, do not add a cheater pipe, and store click-type wrenches backed off to the lowest setting so the spring does not take a permanent set. Calibration should be verified on a schedule; a dropped torque wrench is suspect until it is recertified.
Striking, cutting, and holding tools
- Hammers. A ball-peen hammer is the general shop hammer for striking punches and chisels. A soft-face or dead-blow hammer is used where marring matters — driving a coupling hub, seating a bearing on a driver. Never strike hardened surfaces such as a file, a socket, or another hammer face with a steel hammer; hardened steel can fracture and throw fragments.
- Chisels and punches. A mushroomed head must be ground back before use, because the flared edge breaks off under the hammer blow. Center punches mark the drill start; pin punches drive out roll pins; drift punches align bolt holes and must never be used to force a hole into alignment under load.
- Files. Always fit a handle over the tang. Files cut on the forward stroke only; dragging back dulls the teeth. Clean loading with a file card.
- Hacksaws. Select the blade by tooth pitch so that at least three teeth engage the work at all times — coarse pitch (14 to 18 teeth per inch) for solid bar, fine pitch (24 to 32 teeth per inch) for thin wall tubing and sheet.
- Vises and clamps. Clamp round stock in soft jaws or a V-block; clamping finished shafts in hardened serrated jaws raises burrs that destroy bearing fits.
Portable power tools
Portable electric tools must be grounded through a three-wire cord, be double insulated, or be supplied through ground-fault circuit interrupter protection. A three-prong plug with the ground pin removed is an immediate removal-from-service condition, as is a damaged cord, a missing guard, or a defeated trigger.
Guarding rules that appear in assessment items:
| Tool | Required guarding or setting |
|---|---|
| Bench or pedestal grinder | Work rest set within 1/8 inch of the wheel; adjustable tongue guard within 1/4 inch of the wheel |
| Abrasive wheel | Ring test before mounting; run at operating speed for one minute with the operator standing aside before use |
| Portable circular saw | Lower guard must return automatically |
| Angle grinder | Guard positioned between the wheel and the operator |
Air tools carry their own rules: never point an air hose at a person, use a safety clip or retainer at every coupling to prevent whipping, and shut off and bleed the line before changing sockets or bits.
Measuring and layout tools in the toolbox
The Fundamentals domain expects recognition of the basic measuring kit even though precision measurement has its own module: steel rule, combination square, framing square, scriber, dividers, calipers, chalk line, torpedo and machinist's level, plumb bob, and tape measure. Precision instruments — micrometers, verniers, dial indicators — are covered in Chapter 4 of this guide.
A mechanic needs to break loose a corroded flange nut in an accessible location. Which tool choice is correct?
What are the correct clearance settings on a bench grinder?
Which practice is unacceptable when using hand tools?