Key Takeaways
- Wrenches come in types: open-end, box-end, combination, adjustable, socket, and torque wrenches.
- Screwdrivers match screw types: flathead (slotted), Phillips (+), Torx (star), and hex (Allen).
- Power tools include drills, grinders, sanders, and saws requiring proper safety precautions.
- Fasteners are measured by diameter, thread pitch, and length; SAE (inches) vs metric (mm).
- Measuring tools include tape measures, calipers, micrometers, and levels for precision work.
Last updated: January 2026
Shop Tools and Practices
Quick Answer: The Shop Information (SI) subtest has 11 questions in 6 minutes on CAT-ASVAB. It covers hand tools, power tools, measuring instruments, fasteners, and shop practices.
Hand Tools
Wrenches
Wrenches apply torque to turn fasteners (nuts and bolts).
| Wrench Type | Description | Best Use |
|---|---|---|
| Open-End | U-shaped opening at each end | Quick access, tight spaces |
| Box-End | Enclosed ring, 6 or 12 points | More grip, less rounding |
| Combination | Open-end on one side, box on other | Versatile, most common |
| Adjustable | Jaw width can be adjusted | Various sizes, one tool |
| Socket | Detachable socket on ratchet handle | Fast work, deep access |
| Torque | Measures applied torque (ft-lbs or N-m) | Precise tightening to spec |
| Allen/Hex | L-shaped for hex socket screws | Furniture, machinery |
| Pipe | Adjustable with serrated jaws | Round pipes, plumbing |
Socket Set Components
| Component | Function |
|---|---|
| Sockets | Fit over bolt heads; various sizes |
| Ratchet | Handle with reversible mechanism |
| Extensions | Lengthen reach to recessed bolts |
| Universal Joint | Allows angled access |
| Breaker Bar | Long handle for extra leverage |
Screwdrivers
| Type | Head Shape | Identifier |
|---|---|---|
| Flathead/Slotted | Single slot (-) | Oldest, most basic |
| Phillips | Cross shape (+) | Most common today |
| Pozidriv | Star with extra grooves | Similar to Phillips, more grip |
| Torx | 6-point star | Automotive, electronics |
| Hex/Allen | Hexagonal | Furniture, machinery |
| Robertson | Square recess | Canadian standard, less cam-out |
Pliers
| Type | Function |
|---|---|
| Slip-Joint | Adjustable jaw opening |
| Needle-Nose | Reach into tight spaces; grip small objects |
| Locking (Vise-Grips) | Lock onto object; hands-free holding |
| Channel-Lock | Adjustable, parallel jaws for pipes |
| Diagonal Cutters | Cut wire and small fasteners |
| Wire Strippers | Remove insulation from electrical wire |
Hammers and Mallets
| Type | Head Material | Use |
|---|---|---|
| Claw Hammer | Steel | General purpose, nail pulling |
| Ball-Peen | Steel | Metalwork, riveting |
| Sledge Hammer | Steel | Heavy demolition, driving stakes |
| Rubber Mallet | Rubber | Gentle force without marring |
| Dead-Blow | Sand/shot-filled | Controlled impact, no rebound |
Power Tools
Drilling and Driving
| Tool | Function |
|---|---|
| Electric Drill | Drills holes; drives screws with bit change |
| Drill Press | Stationary drilling; precise, perpendicular holes |
| Impact Driver | High torque for driving screws; rotational impact |
| Impact Wrench | Removes/installs lug nuts; high torque output |
| Hammer Drill | Drilling into masonry; hammering action |
Cutting Tools
| Tool | Function |
|---|---|
| Circular Saw | Straight cuts in wood, powered rotating blade |
| Reciprocating Saw | Demolition, cuts in tight spaces |
| Jigsaw | Curved cuts in wood, thin materials |
| Miter Saw | Angled cuts, precise crosscuts |
| Band Saw | Curved cuts in thick material |
| Table Saw | Ripping long boards; adjustable fence |
| Angle Grinder | Cutting and grinding metal |
Shaping and Finishing
| Tool | Function |
|---|---|
| Belt Sander | Rapid material removal, flat surfaces |
| Orbital Sander | Fine finishing, minimal swirl marks |
| Router | Decorative edges, grooves, patterns |
| Planer | Flattens and thicknesses wood |
| Lathe | Rotates workpiece for shaping (wood or metal) |
Measuring Tools
Length Measurement
| Tool | Precision | Use |
|---|---|---|
| Tape Measure | 1/16 inch | General measurement, flexible |
| Steel Rule | 1/32 inch | Short, precise measurements |
| Folding Rule | 1/16 inch | Rigid, carpentry |
| Caliper | 0.001 inch | Inside/outside dimensions |
| Micrometer | 0.0001 inch | Extremely precise measurement |
Angle and Level
| Tool | Function |
|---|---|
| Level | Checks horizontal and vertical alignment |
| Combination Square | 90 and 45-degree angles; measuring |
| Speed Square | Quick 90/45-degree marking; roof pitch |
| Protractor | Measures any angle |
| Bevel Gauge | Transfers and copies angles |
Fasteners
Bolt and Screw Measurement
Fasteners are identified by:
- Diameter - Major width of threads
- Thread Pitch - Distance between threads (TPI for SAE, mm for metric)
- Length - From under head to tip (screws) or overall (bolts)
SAE vs Metric
| System | Diameter | Thread Pitch | Example |
|---|---|---|---|
| SAE (Imperial) | Fractions or decimals (inches) | Threads per inch (TPI) | 1/4-20 x 1" (1/4" dia, 20 TPI, 1" long) |
| Metric | Millimeters | Millimeters between threads | M6 x 1.0 x 25mm (6mm dia, 1.0mm pitch, 25mm long) |
Common Fastener Types
| Fastener | Description |
|---|---|
| Machine Screw | Threads into tapped hole or nut |
| Wood Screw | Tapered, coarse threads for wood |
| Sheet Metal Screw | Sharp threads, self-tapping |
| Lag Screw | Heavy-duty wood fastener |
| Hex Bolt | Hexagonal head, with nut |
| Carriage Bolt | Round head, square shoulder |
| Stud | Threaded both ends, no head |
| Machine Nut | Threads onto bolts/studs |
| Lock Nut | Resists loosening (nylon insert or deformed) |
| Washer | Distributes load, prevents loosening |
Bolt Grade Markings (SAE)
| Grade | Marking | Material | Use |
|---|---|---|---|
| Grade 2 | No marking | Low carbon steel | Non-critical applications |
| Grade 5 | 3 radial lines | Medium carbon, quenched | General purpose |
| Grade 8 | 6 radial lines | Alloy steel, quenched | High-strength applications |
Tip: More lines = stronger bolt. Count the lines and add 2 for SAE grade.
Test Your Knowledge
Which type of wrench should be used when a specific amount of tightening force is required?
A
B
C
D
Test Your Knowledge
What does "M8 x 1.25 x 30mm" indicate about a metric fastener?
A
B
C
D
Test Your Knowledge
Which tool would provide the most precise measurement of a small metal shaft's diameter?
A
B
C
D
Test Your Knowledge
A SAE bolt with 6 radial lines on its head indicates what grade?
A
B
C
D