1. Hand Tools And Bench Work
Section 7

2. Machine Tool Trade Two categories
Hand tool
Machine tool operations
Importance of hand tools should not be overlooked
Bench work includes operations of laying out, fitting, and assembling

3. Holding, Striking, and Assembling Tools
Unit 22

4. Objectives
Select various tools used for holding, assembling, or dismantling workpieces
Properly use these tools for holding, assembling, and dismantling workpieces

5. Two Classes of Hand Tools
Noncutting
Include vises, hammers, screwdrivers, wrenches and pliers
Used basically for holding, assembling or dismantling parts
Cutting

6. Bench Vise
Jaw caps made of brass, aluminum, or copper to protect the work surface from being marred or damaged
Used to hold small work securely for sawing, chipping, filing, polishing, drilling, reaming, and tapping
Size determined by width of jaws
Solid or swivel base
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7. Ball-Peen Hammer Most common Face: larger striking surface
Peen: smaller, rounded end
Used in riveting or peening operations
Variety of sizes: head mass range 2 oz to 3 lb
Smaller sizes used for layout work
Larger sizes used for general work

8. Soft-Faced Hammers Heads made of plastic, rawhide, copper or lead
Fastened to steel body and replaced when worn
Used in assembling or dismantling parts so finished surface of work not marred
Lead hammers
Used to seat workpiece properly on parallels
Plastic hammer heads
Filled with lead or steel shot
Do not lose shape and last longer than lead hammers
Grasp end of handle for better balance and greater striking force

9. Safety Precautions When Using a Hammer
Be sure handle is solid and not cracked
See head is tight on handle and secured with proper wedge to keep handle expanded in head
Never use with greasy handle or when your hands are greasy
Never strike two hammer faces together

10. Screwdrivers Two most common types Different sizes and styles
Standard or flat blade
Blades for smaller make of round stock
Blades for larger often square for leverage
Phillips
Different sizes and styles
Standard shank
Stubby shank
Offset

11. Phillips Screwdrivers
+ shaped tip for use with Phillips-type recessed screw heads
Manufactured in four sizes: #1, #2, #3, #4
To suit various-sized recesses in heads of fasteners
Use proper size screwdriver
Hold firmly in recess and square with screw

12. Care of a Screwdriver Choose correct size of screwdriver for job
Too small, both screw slot and tip of screwdriver may become damaged
Do not use screwdriver as pry, chisel, or wedge
When tip of standard screwdriver becomes worn or broken, redress to shape

13. Regrinding a Standard Screwdriver Blade
Make sides of blade slightly concave by holding side of blade tangential to periphery of grinding wheel
Grind equal amount off each side of blade
Shape will enable blade to maintain better grip in slot
Retain original taper, width, and thickness of tip and grind end square with centerline
Remove minimum amount of metal
Quench tip frequently in cold water

14. Wrenches Many types used in machine shop work
Each suited for specific purpose
Name derived from use, shape, or construction
Most available in both inch and metric measuring systems

15. Open-End Wrenches Single-ended or double-ended
Openings usually offset at 15º angle
Permits turning nut or bolt head in limited spaces by "flopping" wrench
Double-ended have different-size opening at each end

16. Box-End 12-Point Wrenches
Completely surround nut and useful in close quarters where only small rotation of nut can be obtained at one time
Box end has 12 precisely cut notches around inside face
Notches fit closely over points on outside of nut
Cannot slip when proper size used
Have different size at each end

17. Socket Wrenches Similar to box wrenches Types of drives
Twelve points and surround nut
Types of drives
Ratchet
Torque-wrench handles
Used when nuts or bolts must be tightened to within certain limits

18. Adjustable Wrenches
May be adjusted to within certain range to fit several sizes of nuts or bolt heads
Useful for odd-size nuts or when proper size not available
Can slip when not properly adjusted to flats of nut

19. Allen Setscrew Wrenches
Commonly called hex keys
Hexagonal and fit into recesses of socket head setscrews
Made of tool steel
Available in sets to fit wide variety of screw sizes
Indicated size is distance across flats of wrench
½ outside diameter of Allen setscrew in which used

20. Pin Spanner Wrenches
Specialized wrenches supplied by machine tool manufacturer for use on specific machines
Supplied in various sizes
Fixed-face spanners and adjustable-face spanners positioned in two holes on face of special nut or threaded fitting on machine
Hook-pin spanner used on circumference of round nut
Pin of spanner fits into hole in periphery of nut

21. Hints on Using Wrenches
Always select wrench that fits nut or bolt properly
Pull rather than push on wrench
Always be sure nut is fully seated in wrench jaw
Use wrench in same plane as nut or bolt head
When tightening or loosening nut, give it sharp quick jerk (more effective than steady pull)
Put drop of oil on threads when assembling a bolt and nut to ensure easier removal later

22. Pliers
Useful for gripping and holding small parts for certain machining operations or when assembling parts
Many types and sizes
Names by shape, function or construction

23. Types of Pliers Combination or slip-joint pliers Side-cutting pliers
Adjustable to grip both large and small work
Grip work when small holes must be drilled or for bending or twisting light, thin materials
Side-cutting pliers
Used mainly for cutting, gripping, and bending of small diameter (1/8 in. or less) rods or wires

24. Types of Pliers Needle-nose pliers Diagonal cutters
Available in both straight- and bent-nose types
Useful for holding very small parts, positioning them in hard-to-get-at places and bending wire
Diagonal cutters
Used solely for cutting wire and small pieces soft metal

25. Types of Pliers Vise-grip pliers
Extremely high gripping power because of adjustable lever action
screw in handle allows adjustment to various sizes
Several different styles: standard jaws, needle jaws and C-clamp jaws

26. Hints on Using Pliers Never use plier instead of wrench
Never attempt to cut large-diameter or heat-treated material with pliers
Always keep pliers clean and lubricated