Toothed lock Washers

1. Industry Context

Threaded fastener joints represent more than 70% of mechanical connections across global industrial infrastructure. Despite advances in bonding and welding technologies, bolted assemblies remain dominant because they provide:

• Controlled preload generation
• Field maintainability
• Inspection accessibility
• Replaceability without structural damage

However, vibration, cyclic loading, thermal expansion, and dynamic shear forces introduce a critical engineering challenge:

Loss of clamp load leading to self-loosening.

Toothed lock washers were developed specifically to mitigate this failure mode.

They are extensively deployed across:

• Structural steel assemblies
• Rotating machinery
• Electrical grounding systems
• Automotive components
• Offshore platforms
• Turbine and pump systems
• Rail infrastructure
• Power distribution equipment

For EPC projects and OEM manufacturing, toothed lock washers serve as secondary mechanical locking devices supporting preload retention.

2. Technical Definition

Engineering Definition

A Toothed Lock Washer is a mechanical locking washer incorporating radially formed teeth designed to:

1. Penetrate mating surfaces,
2. Increase friction coefficient,
3. Resist rotational loosening,
4. Maintain clamping force under vibration.

Unlike spring washers that rely on elastic deflection, toothed lock washers function primarily through surface interference locking.

Functional Mechanism

When tightening torque is applied:

1. Teeth plastically deform or bite into:
   • Nut face
   • Bolt head
   • Joint surface
2. Relative rotation becomes mechanically resisted.
3. Micro-slippage between surfaces is prevented.

This creates a mechanical anti-rotation barrier rather than a purely frictional solution.

3. Load Mechanics & Force Behavior

3.1 Bolt Preload Fundamentals

A bolted joint functions as a preloaded spring system.$$F_p = \frac{T}{K \times D}$$

Where:

Parameter	Description
Fp	Preload force
T	Applied torque
K	Nut factor
D	Nominal diameter

Toothed washers contribute by maintaining preload stability rather than increasing preload magnitude.

3.2 Forces Acting on a Joint

Typical industrial joints experience combined loading:

• Axial tensile loads
• Transverse shear
• Cyclic vibration
• Thermal expansion
• Impact loading

Loss of preload occurs due to:

• Embedment relaxation
• Surface creep
• Differential expansion
• Micro-slip under vibration

Toothed lock washers counteract these mechanisms.

3.3 Friction Enhancement Mechanism

The teeth produce:

• Localized high contact stress
• Increased coefficient of friction
• Mechanical interlocking

Typical friction increase:

Surface Condition	μ (Coefficient of Friction)
Plain steel surface	0.12–0.18
With toothed washer	0.30–0.45

This dramatically improves resistance to rotational loosening.

4. Joint Design Principles

4.1 Correct Washer Placement

Engineering rule:

Teeth must engage the rotating component.

Recommended positioning:

Assembly	Washer Location
Bolt & Nut	Under rotating element
Electrical bonding	Against conductive surface
Painted structures	Against metal substrate

4.2 Surface Hardness Compatibility

Tooth penetration requires:$$H_{washer} > H_{joint}$$Hwasher​>Hjoint​

Typical guidance:

Component	Hardness Range
Washer	300–450 HV
Joint surface	< 250 HV

If the joint surface is harder than the washer, locking effectiveness reduces significantly.

4.3 Preload Retention Behavior

Unlike prevailing torque nuts:

• No additional tightening torque required
• Maintains standard torque values
• Compatible with automated assembly

Advantages for EPC installations:

• Predictable torque control
• Easy inspection
• Reusable under controlled conditions

5. Torque–Tension Relationship

Only 10–15% of applied torque produces useful preload.

Torque distribution:

Energy Loss Component	Percentage
Thread friction	40%
Bearing surface friction	45%
Useful preload	15%

Toothed lock washers increase bearing surface friction — improving preload retention stability.

6. Failure Mechanisms Prevented

6.1 Self-Loosening (Junker Effect)

Primary failure under vibration:

• Transverse displacement
• Progressive preload loss
• Complete nut rotation

Toothed washers disrupt slip initiation.

6.2 Fatigue Failure

Reduced preload causes alternating stress:$$\sigma_a = \frac{F_{external}}{A}$$

Maintaining preload minimizes fatigue crack initiation.

6.3 Embedment Relaxation

Surface flattening reduces clamp force.

Tooth penetration minimizes embedment loss.

6.4 Electrical Joint Failure

In grounding systems:

• Paint films increase resistance.
• Teeth cut through coatings ensuring metal-to-metal contact.

7. Design Selection Criteria

Engineers select toothed lock washers based on:

Mechanical Parameters

• Bolt diameter
• Preload level
• Vibration severity
• Joint material hardness

Environmental Conditions

• Corrosion exposure
• Temperature range
• Chemical exposure
• Offshore/sour service

Assembly Constraints

• Available tightening access
• Automation compatibility
• Electrical continuity requirements

8. Functional Advantages Over Other Locking Systems

Locking Method	Mechanism	Limitation
Spring Washer	Elastic force	Relaxation risk
Nylon Lock Nut	Polymer friction	Temperature limits
Adhesive Lock	Chemical bonding	Maintenance difficulty
Toothed Washer	Mechanical biting	Requires suitable surface hardness

9. Engineering Applications Overview

Toothed lock washers are critical where:

• Vibration is moderate to high
• Fastener size is small–medium
• Electrical continuity required
• Space constraints exist

Typical assemblies:

• Control panels
• Motor housings
• Instrumentation mounts
• Automotive assemblies
• Sheet metal structures
• Rail signaling equipment

10. Role within SM Fasteners Product Ecosystem

Within the integrated portfolio of
SM Fasteners, toothed lock washers complement:

• Bolts & nuts
• Precision screws
• Threaded rods
• Rings & retaining elements
• High-performance PEEK fasteners
• Corrosion-resistant specialty alloys

Manufacturing under ISO 9001 quality systems ensures:

Controlled hardness

Dimensional repeatability

Full traceability

Global EPC procurement acceptance

11. Product Types and Variants

Toothed lock washers are classified according to tooth orientation, locking mechanism, and application environment. Selection directly influences locking effectiveness, electrical performance, and joint durability.

11.1 External Tooth Lock Washers

Engineering Characteristics

• Teeth located on outer circumference
• Maximum surface engagement area
• High resistance to rotation
• Superior vibration performance

Functional Advantages

• Higher torsional resistance
• Effective on larger bearing surfaces
• Improved grounding conductivity

Typical Applications

• Structural panels
• Electrical bonding
• Motor assemblies
• Sheet metal fastening

11.2 Internal Tooth Lock Washers

Engineering Characteristics

• Teeth positioned internally
• Hidden under screw head
• Cleaner aesthetic appearance
• Reduced external interference

Advantages

• Suitable for small head screws
• Prevents scratching visible surfaces
• Ideal for precision equipment

Applications

• Electronics assemblies
• Instrumentation
• Control panels
• Automotive interiors

11.3 Internal–External Combination Washers

Engineering Characteristics

• Dual locking teeth configuration
• Maximum gripping action
• High vibration resistance

Recommended Use

• Dynamic machinery
• Rotating equipment
• Heavy industrial environments

11.4 Countersunk Tooth Lock Washers

Engineering Characteristics

• Conical profile
• Designed for countersunk screws
• Maintains flush assembly

Applications

• Aerospace interiors
• Control cabinets
• Precision housings

11.5 Heavy-Duty Toothed Lock Washers

Engineered for:

• High preload bolts
• Structural applications
• High dynamic loading

Characteristics:

• Increased thickness
• Hardened teeth geometry
• Enhanced penetration capability

12. Dimensional Logic and Geometry

Engineering geometry directly determines washer performance.

12.1 Critical Dimensional Parameters

Parameter	Symbol	Engineering Function
Inner Diameter	d₁	Bolt clearance
Outer Diameter	d₂	Load distribution
Thickness	t	Structural stiffness
Tooth Height	h	Penetration ability
Tooth Count	n	Friction multiplication
Pitch Angle	α	Anti-rotation efficiency

Engineering Design Principle

Tooth penetration pressure:$$P = \frac{F}{A_{tooth}}$$

Smaller contact area produces higher localized stress enabling mechanical locking.

12.2 Standard Dimensional Specification Table

(Aligned with SM Fasteners Manufacturing Capability)

Bolt Size	Inner Dia (mm)	Outer Dia (mm)	Thickness (mm)	Typical Tooth Count
M3	3.2	6.0	0.4	8
M4	4.3	8.0	0.5	9
M5	5.3	10.0	0.6	10
M6	6.4	12.0	0.7	11
M8	8.4	16.0	0.8	12
M10	10.5	20.0	1.0	14
M12	13.0	24.0	1.2	16
M16	17.0	30.0	1.6	18
M20	21.0	36.0	2.0	20

Manufactured under ISO-controlled tooling ensuring dimensional repeatability.

12.3 Geometry vs Locking Performance

Geometry Factor	Effect
More teeth	Higher vibration resistance
Greater tooth height	Better penetration
Increased OD	Improved load distribution
Higher hardness	Stronger locking action

13. Applicable International Standards

Toothed lock washers supplied by SM Fasteners conform to globally accepted standards enabling EPC interchangeability.

13.1 DIN Standards

Standard	Description
DIN 6797	External/Internal Tooth Lock Washers
DIN 6798	Serrated Lock Washers
DIN 6905	Heavy Duty Lock Washers

13.2 ISO Standards

Standard	Application
ISO 10669	Serrated Washers
ISO 7089	Plain washer reference dimensions
ISO 898-1	Mechanical properties of fasteners
ISO 3269	Acceptance inspection

13.3 ASTM Standards

Standard	Scope
ASTM F436	Hardened washers
ASTM A684	Steel strip properties
ASTM F606	Mechanical testing
ASTM A967	Passivation (SS)

13.4 British Standards (BS)

Standard	Description
BS 1802	Lock washers
BS 4320	Washer dimensions
BS EN ISO 4759	Fastener tolerances

13.5 Interchangeability Considerations

International procurement often mixes specifications.

System	Equivalent Usage
DIN 6797	ISO serrated washers
BS 1802	DIN compatible
ASTM F436	Heavy structural washers

SM Fasteners engineering verification ensures compatibility across global projects.

14. Thread Standards & Tolerance Compatibility

Although washers are non-threaded, compatibility with thread systems is critical.

Thread Standards Table

Thread System	Standard	Typical Application
Metric Coarse	ISO 261	Global industrial
Metric Fine	ISO 965	Precision equipment
UNC	ASME B1.1	North America
UNF	ASME B1.1	High strength joints
BSW	BS 84	Legacy infrastructure
BSF	BS 84	Heavy engineering
NPT	ANSI B1.20	Piping systems

Tolerance Interaction

Washer ID clearance must accommodate:

$$d_{washer} = d_{bolt} + Clearance$$

Typical clearance: +0.2 to +0.5 mm

Ensures:

• Easy installation
• No binding
• Proper seating

15. Dimensional Inspection Criteria

ISO 9001 manufacturing control at SM Fasteners includes:

• Optical profile measurement
• Go/No-Go gauges
• Statistical Process Control (SPC)
• Tool wear monitoring

16. Weight Chart — Toothed Lock Washers

(Aligned with SM Fasteners export packing calculations)

Size	Approx Weight / Piece (g)	Weight / 100 pcs (kg)
M3	0.10	0.01
M4	0.18	0.018
M5	0.30	0.03
M6	0.45	0.045
M8	0.80	0.08
M10	1.30	0.13
M12	2.00	0.20
M16	4.50	0.45
M20	7.50	0.75

Used for:

• Container load planning
• EPC logistics estimation
• Inventory forecasting

17. Engineering Selection Matrix

Condition	Recommended Washer Type
Electrical grounding	External tooth
Cosmetic assemblies	Internal tooth
Severe vibration	Combination tooth
Flush mounting	Countersunk
Heavy load	Heavy-duty toothed

18. Integration Within SM Fasteners Manufacturing Platform

Through controlled production under ISO 9001 quality management,
SM Fasteners provides:

• Metric & imperial dimensional compliance
• Custom OD/ID geometries
• Special tooth designs
• High-temperature alloys
• PEEK washer variants for electrical insulation

All variants are engineered for EPC, OEM, and global project supply chains.

19. Material Grades and Selection Criteria

Material selection determines the mechanical reliability, corrosion resistance, temperature capability, and service life of toothed lock washers.

Unlike plain washers, toothed lock washers require:

• High surface hardness
• Controlled ductility
• Tooth integrity under preload
• Resistance to wear and relaxation

SM Fasteners manufactures washers from industrial-grade certified raw materials supported by EN 10204 Material Test Certificates (MTC).

19.1 Industrial Material Categories

Carbon Steel

Primary choice for structural and general industrial applications.

Typical Grades:

• C45
• EN8
• SAE 1045
• ASTM A684 strip steel

Characteristics:

• High strength
• Economical
• Suitable for coating systems

Applications:

• Construction assemblies
• Machinery frames
• Automotive components

Alloy Steel

Used where higher mechanical strength or elevated temperature resistance is required.

Typical Grades:

• 4140
• 4340
• EN19
• ASTM A193 Grade B7 compatible assemblies

Advantages:

• Higher hardness potential
• Improved fatigue resistance
• Stable tooth performance

Applications:

• Power plants
• Turbines
• Heavy rotating equipment

Stainless Steel

For corrosion-resistant installations.

Common Grades:

Grade	Standard	Key Feature
A2-70	ISO 3506	General corrosion resistance
A4-80	ISO 3506	Marine & chloride resistance
304	ASTM A240	General industrial
316	ASTM A240	Offshore & chemical
316L	ASTM A240	Welded assemblies

Advantages:

• Corrosion resistance
• Electrical conductivity stability
• Low maintenance

Duplex & Super Duplex Stainless Steel

Used in aggressive offshore and subsea conditions.

Typical Grades:

• UNS S31803
• UNS S32205
• UNS S32750
• UNS S32760

Benefits:

• High strength
• Excellent chloride resistance
• Superior SCC resistance

Nickel-Based Alloys

Critical for extreme environments.

Material	Application
Inconel 625	High temperature turbines
Incoloy 825	Acidic chemical plants
Monel 400	Seawater exposure
Hastelloy C276	Severe corrosion service
Nickel 200	Electrical conductivity applications
SMO 254	High chloride resistance

High-Performance Polymer — PEEK Washers

SM Fasteners supplies PEEK toothed lock washers for specialized applications.

Advantages:

• Electrically insulating
• Lightweight
• Chemical resistant
• Non-magnetic
• Radiation resistant

Applications:

• Semiconductor equipment
• Medical devices
• Aerospace electronics
• LNG instrumentation

20. Material Comparison Table

Material	UTS (MPa)	Yield (MPa)	Corrosion Resistance	Temperature Limit	Relative Cost	Typical Industry
Carbon Steel	600–800	350	Low	300°C	Low	Construction
Alloy Steel	900–1200	700	Moderate	450°C	Medium	Power & Heavy Equipment
SS 304	700	450	Good	425°C	Medium	General Industry
SS 316	750	450	Excellent	500°C	Medium-High	Offshore
Duplex	800	550	Very High	300°C	High	Oil & Gas
Super Duplex	950	700	Extreme	300°C	Very High	Subsea
Inconel 625	1030	690	Outstanding	980°C	Premium	Aerospace/LNG
PEEK	100	90	Chemical Resistant	260°C	Premium	Electronics

21. Mechanical Properties (Grade-Wise)

Toothed washers must maintain hardness without brittleness.

Material Grade	Hardness (HV)	Tensile Strength (MPa)	Recommended Use
Carbon Steel Hardened	350–450	700	General locking
Alloy Steel Q&T	400–500	1000	Dynamic loading
SS A2-70	200–250	700	Corrosion resistance
SS A4-80	240–300	800	Marine
Duplex	260–320	800	Offshore
Inconel	250–350	1030	High temperature

22. Corrosion Resistance vs Environment

Environment	Carbon Steel	SS304	SS316	Duplex	Super Duplex	Nickel Alloys	PEEK
Indoor Industrial	✓	✓	✓	✓	✓	✓	✓
Marine Atmosphere	✗	△	✓	✓	✓	✓	✓
Seawater Immersion	✗	✗	✓	✓	✓✓	✓✓	✓
Acidic Chemicals	✗	△	✓	✓	✓✓	✓✓	✓✓
H₂S / Sour Service	✗	△	✓	✓✓	✓✓	✓✓	✓
High Temperature	△	△	✓	✓	✓	✓✓	△

Legend: ✓ Suitable | △ Limited | ✗ Not recommended

Materials supplied in compliance with NACE MR0175 / ISO 15156 when required.

23. Heat Treatment Processes

Heat treatment is critical for achieving tooth performance.

23.1 Hardening

Purpose:

• Increase surface hardness
• Improve tooth penetration ability

Process:

1. Austenitizing
2. Quenching (oil/polymer)
3. Controlled cooling

Typical hardness target:
38–48 HRC

23.2 Tempering

Objective:

• Reduce brittleness
• Improve fatigue resistance

Temperature range:
150–450°C depending on material grade.

23.3 Case Hardening / Carbonitriding

Used for:

• Thin washers
• Enhanced wear resistance

Benefits:

• Hard surface
• Tough core

23.4 Solution Annealing (Stainless Steel)

Required for corrosion resistance restoration.

Process:

• Heating to ~1050°C
• Rapid quenching

Prevents sensitization and intergranular corrosion.

23.5 Hydrogen Embrittlement Control

Critical for coated high-strength washers.

Preventive Controls:

• Baking after electroplating
• Controlled hardness limits
• ISO 4042 compliance

24. End-to-End Manufacturing Workflow

SM Fasteners operates under ISO 9001 process control ensuring complete traceability.

24.1 Raw Material Verification

Incoming inspection includes:

• Heat number verification
• Chemical analysis
• Spectrometer testing
• MTC review

24.2 Strip Preparation

• Precision slit coils
• Surface cleaning
• Thickness verification

24.3 Precision Stamping / Blanking

High-speed progressive dies produce:

• Inner diameter
• Outer diameter
• Tooth geometry

Critical tolerance control:
±0.02–0.05 mm

24.4 Tooth Forming Operation

Teeth are formed through controlled cold forming.

Engineering objective:

• Maintain sharp tooth profile
• Avoid micro-cracking

24.5 Heat Treatment

Automated furnace systems provide:

• Uniform hardness
• Controlled atmosphere
• Batch traceability

24.6 Deburring & Surface Conditioning

Processes:

• Vibratory finishing
• Shot blasting
• Edge smoothing

Ensures:

• Safe handling
• Accurate seating
• Consistent torque performance

24.7 Final Inspection & Sorting

Includes:

• Optical inspection
• Hardness testing
• Dimensional sampling
• Statistical quality control

25. Surface Finishing & Coating Engineering

Surface treatment determines corrosion performance and service life.

25.1 Coating Types

Coating	Standard	Thickness	Typical Use
Plain Oil	—	Minimal	Indoor
Zinc Plating	ISO 4042	5–12 µm	General industry
HDG	ISO 10684	40–80 µm	Structural steel
Zinc Flake	ASTM F1136	8–12 µm	Automotive
Mechanical Galvanizing	ASTM B695	50 µm	Heavy assemblies
Black Oxide	ASTM D769	1 µm	Indoor machinery
Passivation	ASTM A967	—	Stainless steel
PTFE/Xylan	Project Spec	20–30 µm	Low friction
Dacromet/Geomet	OEM Specs	8–12 µm	Corrosion-critical

25.2 Surface Finish Performance Comparison

Coating	Corrosion Resistance	Friction Control	Temperature Limit
Zinc	Medium	Moderate	120°C
HDG	High	High friction	300°C
Zinc Flake	Very High	Stable	300°C
PTFE	Excellent	Low friction	260°C
Passivated SS	Excellent	Stable	500°C

25.3 Coating Selection Engineering Criteria

Selection depends on:

• Galvanic compatibility
• Required salt spray hours
• Operating temperature
• Electrical conductivity needs
• Assembly torque stability

26. Traceability & Process Integration

Every washer manufactured by
SM Fasteners
is traceable through:

• Heat number marking
• Batch identification
• Inspection records
• Heat treatment reports
• Coating certification

Integrated ISO 9001 system ensures global EPC acceptance.

27. Inspection & Quality Control Framework

Toothed lock washers are small components but critically influence joint reliability, vibration resistance, and electrical continuity. For EPC and OEM supply, inspection requirements are equivalent to structural fasteners.

SM Fasteners integrates inspection within an ISO 9001 quality management system, ensuring repeatable mechanical performance and global project acceptance.

27.1 Incoming Material Inspection

Verification performed prior to production:

Inspection Activity	Method	Standard
Material certification review	MTC validation	EN 10204 3.1
Chemical composition	Optical emission spectroscopy	ASTM E415
Strip thickness verification	Digital micrometer	ISO 9445
Surface quality	Visual inspection	ISO 8785

Objective: Prevent non-conforming metallurgy entering production.

27.2 In-Process Manufacturing Inspection

Stage	Inspection
Stamping	OD/ID dimensional control
Tooth forming	Profile verification
Heat treatment	Hardness testing
Deburring	Edge condition inspection
Coating	Thickness measurement

Statistical Process Control (SPC) ensures dimensional stability across high-volume manufacturing.

27.3 Final Inspection Requirements

Test	Purpose
Dimensional inspection	Fit and seating accuracy
Hardness testing	Tooth penetration capability
Surface coating thickness	Corrosion performance
Visual inspection	Burrs & deformation
Functional seating test	Locking performance validation

Inspection acceptance aligned with ISO 3269.

27.4 Mechanical & Metallurgical Testing

Applicable verification methods:

• Rockwell/Vickers hardness testing
• Microstructure examination
• Salt spray corrosion testing (ASTM B117)
• Torque retention testing
• Metallographic analysis

27.5 Positive Material Identification (PMI)

Required for:

• Duplex
• Super Duplex
• Nickel alloys
• Critical oil & gas service

PMI confirms alloy chemistry traceability.

27.6 Non-Destructive Examination (NDT)

Where specified by EPC projects:

• Magnetic particle inspection
• Dye penetrant testing
• Micro-crack detection post heat treatment

27.7 Documentation & Certification

Typical supply documentation:

• EN 10204 3.1 / 3.2 MTC
• Heat treatment report
• Coating compliance certificate
• Dimensional inspection report
• Certificate of Conformity (CoC)

28. Mechanical Performance & Proof Strength

Toothed lock washers themselves do not carry tensile load but must withstand compressive stresses from bolt preload.

Mechanical Property Reference Table

Washer Material	Hardness Range	Compressive Strength (MPa)	Service Class
Hardened Carbon Steel	350–450 HV	900	Standard Industrial
Alloy Steel	400–500 HV	1100	Heavy Duty
SS A2-70	200–250 HV	600	Corrosion Resistant
SS A4-80	240–300 HV	700	Marine
Duplex SS	260–320 HV	850	Offshore
Inconel 625	250–350 HV	1000	High Temperature

29. Tightening Torque Engineering

Correct torque application ensures washer effectiveness.

Torque Relationship

$$T = K \times D \times F$$

Where:

• T = Torque
• K = Nut factor
• D = Bolt diameter
• F = Desired preload

Typical nut factors:

Condition	Nut Factor (K)
Dry	0.20
Light oil	0.18
Zinc coated	0.16
PTFE coated	0.12

Tightening Torque Chart (Typical Engineering Values)

Bolt Size	Property Class	Dry Torque (Nm)	Lubricated Torque (Nm)
M5	8.8	5	4
M6	8.8	9	7
M8	8.8	22	17
M10	8.8	45	36
M12	8.8	78	62
M16	8.8	190	150
M20	8.8	370	295

Toothed lock washers do not require torque increase.

30. Preload Calculation — Worked Engineering Example

Design Requirement

Bolt Size: M10
Property Class: 8.8
Desired preload: 70% of proof load

Proof load (M10-8.8):$$F_p = 36\,kN$$

Required preload:$$0.7 \times 36 = 25.2\,kN$$

Torque required:$$T = 0.2 \times 0.01 \times 25200$$

$$T = 50.4\,Nm$$

Recommended Torque ≈ 45–50 Nm

Toothed washer maintains this preload under vibration.

31. Failure Mechanisms & Engineering Prevention

Failure Mode	Cause	Washer Contribution
Self-loosening	Vibration	Teeth resist rotation
Embedment relaxation	Surface flattening	Penetration stabilizes joint
Fretting corrosion	Micro movement	Eliminates slip
Electrical resistance rise	Coatings	Teeth cut through paint
Fatigue cracking	Preload loss	Maintains clamp force

32. Industry Application Mapping

Construction & Structural Steel

• Steel frames
• HVAC supports
• Cladding assemblies
• Bridge accessories

Oil & Gas (Upstream–Downstream)

• Instrument mounting
• Control panels
• Valve actuators
• Offshore electrical bonding

NACE-compliant material options available.

Power Generation

• Turbine housings
• Switchgear assemblies
• Generator terminals

Petrochemical & Chemical Plants

• Pump skids
• Pipe support systems
• Reactor instrumentation

LNG & Offshore Platforms

• Marine corrosion-resistant assemblies
• Explosion-proof equipment
• Subsea monitoring systems

Automotive & Heavy Equipment

• Engine accessories
• Transmission assemblies
• Hydraulic equipment

Railways & Infrastructure

• Signaling systems
• Electrical grounding
• Rolling stock assemblies

Shipbuilding & Marine Engineering

• Navigation equipment
• Deck hardware
• Electrical continuity joints

PEEK Washer Applications

SM Fasteners provides engineered PEEK toothed lock washers for:

• Electrically isolated joints
• Cryogenic LNG systems
• Semiconductor cleanrooms
• Aerospace electronics

33. Thread Standards & Tolerance Compatibility

Thread Type	Standard	Typical Region
Metric Coarse	ISO 261	Global
Metric Fine	ISO 965	Precision equipment
UNC	ASME B1.1	USA
UNF	ASME B1.1	Aerospace
BSW	BS 84	Legacy UK
BSF	BS 84	Heavy engineering

Washer clearance tolerances designed to accommodate all systems supplied by SM Fasteners.

34. Surface Finish Selection Matrix

Environment	Recommended Finish
Indoor machinery	Zinc plated
Outdoor structural	Hot dip galvanized
Offshore	SS316 / Duplex
Chemical plant	PTFE / Nickel alloy
High temperature	Inconel
Electrical bonding	Passivated stainless

35. Weight Chart — Export & Logistics Planning

(Aligned with SM Fasteners production database)

Size	Weight/Piece (g)	Weight/100 pcs (kg)
M3	0.10	0.01
M4	0.18	0.018
M5	0.30	0.03
M6	0.45	0.045
M8	0.80	0.08
M10	1.30	0.13
M12	2.00	0.20
M16	4.50	0.45
M20	7.50	0.75

Used for:

• Container optimization
• Freight calculations
• EPC material planning

36. Export Packaging & Global Supply Capability

SM Fasteners supports international EPC supply requirements.

Industrial Packaging

• VCI anti-corrosion packing
• Moisture barrier bags
• Batch labeling
• Thread protection

Export Crating

• ISPM-15 compliant wooden crates
• Palletized shipments
• Vacuum sealing for offshore projects
• Barcode traceability

Supply Chain Capabilities

• Project-wise batch control
• Mixed fastener kits
• Custom labeling
• Vendor documentation packages

37. Documentation Supplied with Shipments

Typical export documentation:

• Material Test Certificates (EN 10204 3.1/3.2)
• Inspection Reports
• Heat Treatment Records
• Coating Compliance Certificates
• Certificate of Conformance
• Packing List & Traceability Sheet

38. Integration with SM Fasteners Engineering Systems

Under ISO 9001 quality governance,
SM Fasteners delivers:

• Precision stamping & heat treatment
• Advanced alloy manufacturing
• PEEK fastener engineering capability
• Custom dimensional design
• Full international standards compliance
• Reliable EPC and OEM supply readiness

39. Engineering Summary

Toothed lock washers provide a mechanically reliable, compact, and standards-compliant locking solution for modern industrial assemblies.

Key engineering outcomes:

• Maintained preload under vibration
• Improved electrical continuity
• Reduced fatigue failure risk
• Compatibility with global fastener systems
• Reliable performance across severe industrial environments

When manufactured under certified systems with controlled metallurgy and inspection discipline, toothed lock washers become a critical component supporting long-term joint integrity.