1. WPP-Fasteners & Hardware
T-DAP MAP 32
WPP-Fasteners & Hardware

2. Agenda Fastener terminology & application
Metric, Imperial and non-standard hardware
Physical properties of hardware
Factors that affect torque
Fastener chemicals

3. Fasteners & hardware Function: To hold things together
Most common automotive type – threaded fastener

4. Fasteners & hardware Automotive hardware includes: bolts / nuts screws
studs
locking devices
pins
rivets
keys
washers
retaining rings
helicoils

5. Fasteners & hardware
Threaded fasteners are available in many sizes, designs & threads
Threads can be rolled - definition
“Threads formed by tightly pressing or rolling the piece of stock between serrated dies. This is the most common method of creating threaded fasteners today.”
Rolled threads = 30% stronger and better fatigue resistance

6. Fasteners & hardware Threads can be cut - definition
“Threads formed by cutting into a piece of stock.”

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10. Fasteners & hardware
Fasteners are made to imperial or metric measurements
4 classifications of threads (imperial)
Unified National Coarse (UNC)
Unified National Fine (UNF)
Unified National Extra fine (UNEF)
Unified National Pipe Thread (NPT,UNPT)
Metric fasteners available in standard, fine and superfine

11. Fasteners & hardware Cap screws (a.k.a. bolts) nomenclature
S = shank diameter
T = thread diameter
R = root diameter

12. Fasteners & hardware
When measuring fastener diameter, always use “T” thread diameter which measures at the crest of the thread
Beware: hex head size is not bolt size

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14. Fasteners & hardware
When measuring fastener diameter, always use “T” thread diameter which measures at the crest of the thread
Beware: hex head size is not bolt size

15. Fasteners & hardware Bolts are usually made from steel
Different grades of steel give different strengths
Property Class
Imperial bolts (fractional) have lines in the head of the bolt
Metric bolts have decimal number in the head of the bolt

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17. Fasteners & hardware Head markings other than property class
Manufacturer specific (warranty purposes)

18. Max pound force per square inch
Fasteners & hardware
Approximate yields strengths
Imperial
Metric
Max pound force per square inch
Grade 1
Grade 5
Grade 7
Grade 8
4.5
8.8
9.8
10.9
60,000
120,000
130,000
150,000

19. Fasteners & hardware Property class explained
Metric bolts – numerical e.g. 10.9
10 represents the grade or tensile strength
9 represents the yield point as a percentage of tensile strength
10 = 145,000 lbs/inch tensile strength
9 = 130,500 lbs/inch yield strength

20. Fasteners & hardware Understanding bolt strength Tensile strength
Yield strength
Shear strength

21. Fasteners & hardware Tensile strength (grade)
Sometimes called ultimate strength, is the maximum stress level a material can withstand without breaking
Under how much pressure will the fastener break
Factors
Materials
Diameter of bolt
Accelerators?

22. Fasteners & hardware Yield strength
Maximum strength a material can withstand and return to its original form without damage or deformation
Identifying a bolt that has reached yield

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24. Fasteners & hardware Shear strength
The force required to shear or split the bolt into two parts
Approx 60% of ultimate tension strength

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26. Fasteners & hardware M8 X 1.5 X 24 ½ X 13 X 1 M = metric 8 = ? 1.5 = ?
24 = ?
½ X 13 X 1
Imperial
½ = ?
13 = ?
1 = ?

27. Fasteners & hardware Studs Rods with threads on both ends
Can have different threads on each end
Why a stud/nut vs. a bolt?
Soft material where coarse threads are needed but requires clamping force of fine threads
Remember the finer the thread the greater holding power & resistance to vibration
Remember coarse threads for soft material
Square, cross, circle

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29. Fasteners & hardware Nuts Most common is hex nut
Grade (tensile strength only) of nut must match bolt grade
If a grade 8 bolt were used with a grade 5 nut – connection is max grade 5

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31. Fasteners & hardware Types of nuts Hex nut
Hex nut – nylon insert (lock nut)
Hex jam nylon lock nuts
Cap nuts
Flanged serrated
Wing nuts
K-nuts
Prevailing torque lock nuts
Castellated

32. Fasteners & hardware Washers Different washers have defined purposes
Flat washers
spread load of tightening nut or bolt
prevents digging
Copper – sealing – crush
Lock washers
Lock head of bolt or nut to prevent loosening

33. Fasteners & hardware Types of washers available in metric & imperial
Flat
USS
SAE
Fender
Lock washers
Split
Internal teeth
External teeth

34. Fasteners & hardware Pins Push pins Cotter pins Bend once
One time use only! Throw away!
Use with castellated nuts/shafts
Available in different sizes and lengths

35. Fasteners & hardware

36. Fasteners & hardware Rivets Used for attaching two pieces of material
Rivet gun

37. Fasteners & hardware

38. Fasteners & hardware Keys Used for aligning shafts
Used for preventing pulley rotation on shaft
Key sits in keyway machined into respective parts
Types
Flat/squre
woodruff

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43. Fasteners & hardware
Retaining rings and snap rings are fasteners used to axially position a component on a shaft or in a bore.  The primary retaining ring type can be internal or external.  Internal retaining rings fit into a housing or bore.
Note diameter and thickness of fastener for proper application

44. Fasteners & hardware
Use special pliers for retaining ring installation and removal
Under tension – watch for launched rings

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48. Fasteners & hardware
Thread repair
Tap/die set
Helicoil ™

49. Fasteners & hardware
Helicoil insert are made from high quality stainless steel wire, with a diamond shaped cross section, wound to the shape of a spring thread. The insert, which is larger in diameter than the tapped hole, is compressed during installation then allowed to spring back, permanently anchoring the insert in the tapped hole. Because of its larger diameter, the Helicoil Insert has a greater contact area and is normally stronger than the original threads. (toolsnextday UK)

50. Fasteners & hardware
Step 1 – Drill to clear out bad threads **right size please
Step 2 – tap with helicoil tap
Step 3 – insert helicoil
Step 4 – knock tab *if in combustion chamber break off and pull out with pliers

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Step 1

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Step 2

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Step 3

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Step 4

55. Fasteners & hardware
OEMs may recommend the use of sealant or lubricant per application
Antiseize
May recommend in aluminum
Thread sealants
Used on fasteners tightened in oil cavities or coolant passages
Threadlocker
Prevents bolts from loosening due to vibration

56. Fasteners & hardware
Major manufacturer in sealants/lubricants/threadlockers is Loctite

57. Fasteners & hardware Factors that affect torque Thread condition
Damaged/Burred
Corrosion
Lubrication
Reduces friction (even water) – changes torque value
Temperature
Heat vs. cold – shrinkage vs. expansion
Fastener composition
Different materials have different torque values

58. Fasteners & hardware Factors that affect torque Torque Chart
What do you do?
Always follow manufacturer literature on fastener torque
Apply lubrication when specified otherwise dry
*wheel nuts
Torque Chart

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