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Industrial Scaffolding Coupler & Fitting Manufacturer

EK Scaffolding is a leading Chinese manufacturer and global exporter of high-quality scaffolding couplers and fittings. Built with premium Q235 and Q355 steel, our product range includes drop forged coupler, pressed coupler, and cast iron couplers engineered to meet strict international standards, including BS1139, EN74 (Class A & B), and JIS.
With thousands of containers shipped worldwide to over 30 countries—including the UK, Germany, France, Norway, Australia, and across Europe—we supply high-durability right angle coupler, swivel coupler, putlog coupler, beam coupler, board retaining coupler, and sleeve couplers.

 

  Looking for reliable direct-factory supply? Contact us today for a fast quote and technical datasheet!

Explore Our Scaffolding Coupler Series

According to different usage scenarios and different sizes of copper pipes, the most commonly used scaffolding coupler specifications are: 48.3*48.3. There are also some special specifications as shown in the following table:
 

According to different sizes

Double Coupler

Swivel Coupler

48.3*34

48.3*34

34*34

34*38

48.3*38

48.3*38

38*38

38*42

48.3*42

48.3*42

42*42

42*60

48.3*48.3

48.3*48.3

48.3*60.3

-

48.3*60

48.3*60

60*60

60*76

48.3*76

48.3*76

76*76

86*89

48.3*60.3

48.3*89

89*89

-

60.3*60.3 60.3*60.3 - -
 
Sleeve/Joint Coupler Girder Coupler Putlog/Single Coupler Board Retaining Coupler Distance Coupler SK - Bjelke Klips Dobbelt Oppheng Klips Gravelock Ring Coupler
48.3*48.3 48.3*45 48.3*48.3 48.3*38 48.3*74 48.3 48.3*48.3 48.3 48.3
40*40 48.3*50 - 48.3*45 48.3*98 - - - -
- 48.3*55 - 38*38 - - - - -

Our scaffolding coupler has obtained many international certificates, such as EN 74-1:2005 and EN 74-1:2005 Clause 7.4.3, etc.

 

Drop Forged Double Coupler

Summary of Results:

No.

Test Item

Test Method

1

Slipping Force

EN 74-1:2005

2

Failure Force

EN 74-1:2005

Slipping Force: The first time the pressure is applied, when the pressure is greater than 10kN, the sliding distance of the scaffolding steel pipe should be less than 7mm. The test result is: when the pressure is 10.6kN, the sliding distance of the steel pipe on the scaffolding coupler is less than 7mm, which meets the standard requirements.
The second pressure is applied, when the pressure is greater than 15kN, the sliding distance of the steel pipe on the scaffolding coupler should be between 1mm-2mm. The test result is: under a pressure of 30kN, the sliding distance of the second test is less than 1mm, which is consistent with Claim.

Failure Force:The bearing weight of the scaffolding coupler must reach 20KN. The test result: It can bear a weight of 24KN, and the destructive resistance of the coupler reaches the standard.

Test Results:

Test Clause

Test Item

Test Requirement

Test Result

Conclusion

 

7.2.1

 

 

Slipping force

 

△1≤7mm, Fs,5%≥10.0kN

△1=7mm, Fs,5%=15.88kN

 

Pass

 

1mm≤△2≤2mm, Fs,5% ≥15.0kN

1mm≤△2≤2mm, Fs,5%=15.91kN

7.2.2

Failure force

Ff,5%/γR2 ≥30.0kN

Ff,5%/γR2=50.63kN

Pass

Right-Angle Coupler Specifications Table

Item

Drop Forged Right Angle Coupler

Cold Pressed Right Angle Coupler

Manufactur Process

Drop Forged

Cold Pressed

Material

High-quality Q235 / Q355 carbon structural steel

High-quality Q235 steel plate

Pipe (OD)

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Standard

BS1139 / EN74 Class B / JIS

BS1139 / EN74 Class A / JIS

Bolt Specification

T-bolt M12 / M14 × 88 mm

Eye Bolt M12 × 85 mm

Nut Specification

21mm Flange Nut (1/2" BSW) / 22mm / 23mm

21mm / 22mm hex nut

Bolt Grade

Available in Grade 4.8 or Grade 8.8 high-strength options.

Grade 4.8 / Grade 8.8 available

Weight

1.00 – 1.15 kg/piece

0.85 - 0.95 kg / piece

Slip Resistance

≥ 15.0 kN (Complies with EN74 Class B standard)

≥ 10.0 kN (Complies with EN74 Class A standard)

Ultimate Load

≥ 30.0kN

≥ 20.0kN

Surface Treatment

Electro-Galvanized) / HDG

Electro-Galvanized / HDG

MOQ

1,000 pcs

2,000 pcs

Packaging

25 pieces/woven bag, 1,000 pieces/steel pallet

30 pieces/woven bag, 1,200 pieces/wooden pallet

Application

Heavy-duty steel pipe scaffolding, high-rise buildings, petrochemical industry, large-scale bridges

Standard civil buildings, masonry scaffolding, light-duty construction

Additional Notes:
Nut & Spanner Compatibility:
21mm (1/2" BSW): Standard specification for UK and European markets (compatible with 21mm spanner).
22mm (M14): Standard for international markets, as well as the Middle East and Southeast Asia.
23mm: Specified standard for Australian and New Zealand markets.
Custom Tube Diameter:
In addition to the standard Ø48.3mm, custom options are available for Ø60.3mm or reduced-size right-angle couplers (Ø38mm / Ø42mm).

Product Features & Customization:
High Load Capacity: Designed according to EN74 Class B standards, making it ideal for heavy-duty scaffolding, high-rise building construction, shipbuilding, and oil & gas projects.
Nut Size Options:
21mm (1/2" BSW Nut): UK, European & Middle East markets.
22mm / 23mm Nut: Australian, New Zealand & Southeast Asian markets.
7/8" (22.2mm) Hex Nut: American & Canadian markets.

OEM Service: Custom logo embossing, washer thickness, bolt grade, and packaging options are available upon request.
 

Drop Forged Swivel Coupler  Class “B”

Under normal circumstances, it is difficult to reach B grade, but we reached

 
Under normal circumstances, it is difficult to reach B grade, but we reached.
 

Summary of Results:

No.

Test Item

Test Method

1

Slipping Force

EN 74-1:2005

2

Failure Force

EN 74-1:2005

 

Test Results:

Test Clause

Test Item

Test Requirement

(Swivel coupler, Class B)

Test Result

Conclusion

 

7.2.1

 

 

Slipping force

 

△1≤7mm, Fs,5%≥10.0kN

△1≤7mm, Fs,5%=10.6kN

 

Pass

 

1mm≤△2≤2mm, Fs,5% ≥15.0kN

Fs=30kN, △2˂1mm

7.2.2

Failure force

Ff,5%/γR2 ≥20.0kN

Ff,5%/γR2=24.4kN

Pass

Swivel Coupler Specifications Table

Item

Drop Forged Swivel Coupler

Pressed Swivel Coupler

Manufacturing Process

360° Drop-Forged + Central Swivel Pin

Cold Stamping + Rotary Riveting

Material

High-quality Q235B / Q355B structural steel

High-quality Q235 steel plate

Pipe OD

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Swivel Angle

360-degree free rotation with no blind spots

360-degree free rotation with no blind spots

Thickness

≥4.0 – 4.5 mm (High-rigidity cover plate)

≥3.0 - 3.5 mm

Standard

EN74-1 Class B / Class A / BS1139 / AS/NZS 1576.2

BS1139 / EN74 Class A

Center Pin

Ø16 mm – Ø18 mm High-strength solid forged rivets

Ø14 mm – Ø16 mm High-strength carbon steel rivets

Bolt Spec

T-Bolt M12 / M14 × 88 mm

Eye Bolt M12 × 85 mm

Nut Spec

21mm (1/2" BSW) / 22mm / 23mm (Australian Standard)

21mm / 22mm Hex Nut

Unit Weight

1.10 kg – 1.25 kg/piece (standard weight 1.15 kg)

0.90 kg – 1.00 kg/piece

Slip Resistance

≥15.0 kN (Complies with Class B standards)

≥10.0 kN (Complies with Class A standards)

Failure Load

≥28.0 - 30.0kN

≥20.0kN

Surface treatment

Electro-Galvanized) / HDG

Electro-Galvanized / HDG

MOQ

1000 pcs

2000 pcs

Packaging

25 pieces/woven bag, 1,000 pieces/steel pallet

30 pieces/woven bag, 1,200 pieces/wooden pallet

Application

Diagonal braces, curved or irregularly shaped scaffolding, shipbuilding, and petrochemical industries.

Temporary edge protection railings, diagonal bracing, and event stage setup.

Difference Between Right-Angle Coupler and Swivel Couplers:

Right-Angle Coupler (Right Angle / Double): Secures a fixed 90° intersection; primarily used to connect main load-bearing members (standards and ledgers).

Swivel Coupler: Allows for 360° rotation; specifically designed to connect diagonal bracing tubes, ensuring the lateral stability of the overall scaffolding structure.

 

Safety Note Regarding the Center Pin:

The performance of a swivel coupler hinges on its central rotating rivet. Forged swivel couplers utilize large-diameter (Ø16mm/Ø18mm) hot-forged rivets that resist loosening or breakage under high tensile loads, ensuring compliance with EN74-1 Class B safety standards.

Pressed Sleeve Coupler

Summary of Results:

No.

Test Item

Test Method

1

Bending Moment Resistance

EN 74-1:2005 Clause 7.4.3

2

Slipping Force

EN 74-1:2005 Clause 7.2.1

 

Test Results:

Test Item

Test Result

Test Requirement 

(Sleeve coupler, Class B)

Conclusion

Bending Moment Resistance

△4=5mm, Mb,5% =1.43kNm

△4=5mm, Mb,5% ≥1.4kNm

Pass

Sleeve Coupler Detailed Specifications Table

Item

Pressed Steel Sleeve Coupler / Joint Clamp

Cast / Forged Sleeve Coupler

Manufacturing Process

High-quality Cold Pressed

Cast or Drop-Forged

Material

High-quality Q235 carbon steel plate (thickness ≥ 3.5–4.0 mm)

Malleable iron or Q235B forged steel

Pipe OD

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Connection Method

External End-to-End Joint

External End-to-End Joint

Overall Length

200 mm – 210 mm

200 mm - 210 mm

Standard

EN74-1 Class A / BS1139 / AS/NZS 1576.2

EN74-1 / BS1139 Standard

Bolt Spec

Central long bolt M12/M14 × 75 mm or M12 × 80 mm

Center Hex Bolt M12 / M14 × 75 mm

Nut Spec

21mm (1/2" BSW) / 22mm / 23mm (Australian Standard)

21mm/22mm hex nut

Unit Weight

0.95 kg – 1.05 kg/piece (standard weight 1.00 kg)

1.10 kg – 1.25 kg/piece

Tensile Load

≥6.0 kN (Complies with EN 74-1 tensile strength requirements for couplers)

≥6.0 - 9.0 kN

Ultimate Load

≥15.0kN

≥18.0kN

Surface treatment

Electro-Galvanized / HDG

Electro-Galvanized / HDG

MOQ

1000 pcs

1000 pcs

Packaging

20 pieces/woven bag, 1,000 pieces/steel pallet

20 pieces/woven bag, 1,000 pieces/steel pallet

Top Markets

The UK, Ireland, New Zealand, Australia, Malaysia

Parts of Europe, Oil and gas projects in the Middle East

Differences between Sleeve Couplers and Joint Pins:

Sleeve Coupler (External Connection): Wraps around the exterior of the steel tube and is secured with bolts; offers superior resistance to bending and tension, serving as the standard external connecting component compliant with EN74 / BS1139 specifications.

Joint Pin (Internal Connection): Inserts into the interior of the steel tube and expands to secure the connection; primarily used for internal joining, though its resistance to bending moments is lower than that of the sleeve coupler.

 

Nut and Tool Compatibility:

UK & Ireland: Standardized with 21mm (1/2" BSW) nuts.

Australia & New Zealand: 23mm nuts are recommended; hot-dip galvanizing (HDG) is mandatory to ensure durability for outdoor use in coastal environments.

Putlog / Wrapover Coupler

Summary of Results:

No.

Test Item

Test Method

1

Slipping Resistance

BS 1139-2.2:2009+A1:2015 Clause 7 & Annex A.2

 

Test Results:

Test Item

Test Result

Test Requirement

Conclusion

Slipping Resistance

1mm≤△2≤2mm, Fs,5% =1.83kN

1mm≤△2≤2mm, Fs,5% ≥1.04kN

Pass

Putlog / Wrapover Coupler: Detailed Specifications Table

Name

Pressed Steel Putlog / Wrapover Coupler

Drop Forged Putlog Coupler

Manufacturing Process

High-quality cold stamping (Cold Pressed)

Hot Die-Forged Cover Plate/Base

Material

High-quality Q235 carbon structural steel plate

High-quality Q235B / Q355B forged steel

Pipe OD

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Type

Wrapover Single Clamp

Forged Single Clamp

Thickness

≥3.0 - 3.5mm

≥4.0mm

Standard

BS1139 Standard / EN74

BS1139 / EN74 Standard

Bolt Spec

T-bolt M12×85 mm or M12×88 mm

T-bolt M12 × 88 mm

Nut Spec

21mm (1/2" BSW) / 22mm / 23mm (Australian Standard)

21mm/22mm/23mm

Unit Weight

0.60 kg – 0.70 kg/piece (standard weight 0.63 kg)

0.68 kg - 0.75 kg/ piece

Slip Resistance

≥0.63 kN (Complies with BS1139 standard for non-load-bearing single couplers)

≥1.0kN

Surface Treatment

Electro-Galvanized / HDG

Electro-Galvanized / HDG

MOQ

2000 pcs

1000 pcs

Packaging

35 pieces/woven bag, 1,400 pieces/steel pallet

30 pieces/woven bag, 1,200 pieces/steel pallet

Top Markets

The UK, Australia, South America, Vietnam, South Africa

UK, Middle East oil and gas engineering, Europe

Core Applications and Limitations of Putlog Couplers:

Primary Use: Specifically designed to secure putlogs (transoms) to ledgers to support scaffold boards, or to secure guardrails.

Safety Warning (Non-load-bearing coupler): Putlog couplers feature a single-clamp design; they are strictly prohibited for use in the primary load-bearing connections between standards (verticals) and ledgers (horizontals). Right-angle (double) couplers must be used for primary load-bearing joints.

 

Market Preferences and Nut Specifications:

UK & Ireland: High demand (putlog transoms are widely used in standard scaffolding erection); universally equipped with 21mm (1/2" BSW) flange nuts.

Australia & New Zealand: Compatible with 23mm nuts; hot-dip galvanized (HDG) finish is commonly required.

Girder / Gravlock Coupler

Summary of Results:

No.

Test Item

Test Method

1

Strength test

AS/NZS 1576.2:2016 Appendix L

2

Slip test along tube

AS/NZS 1576.2:2016 Appendix M

3

Slip test along tube a flange

AS/NZS 1576.2:2016 Appendix N

 

Test Results:

Test Clause

Test Item

Test Requirement

Test Result

Conclusion

Appendix L

Strength test

P=30.0kN, neither flange clamp shall show any permanent set

P=30.0kN, neither flange clamp showed any permanent set

Pass

Appendix M

Slip test along tube

P=12.5kN, Slippage ≤ 6mm

P=12.5kN, Slippage<6mm

Pass

Appendix N

Slip test along tube a flange

P=12.5kN, Slippage ≤ 6mm

P=12.5kN, Slippage<6mm

Pass

Girder / Gravlock Coupler Detailed Specifications Table

Name

Drop Forged Gravlock / Girder Coupler

Cast / Pressed Steel Beam Clamp

Manufacturing Process

Heavy-Duty Drop Forging (One-Piece)

Casting (Malleable Iron / Cast Steel) or Composite Stamping

Material

High-quality Q235B / Q355B / 45# high-strength carbon steel

High-toughness malleable iron or Q235 steel

Pipe OD

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Ø48.3 mm (standard 1.9" scaffolding steel tube)

Clampable Flange Thickness

Maximum clamping capacity: 45 mm

Maximum clamping capacity: 35 mm – 40 mm

Design Structural Configuration

Must be used in pairs

Must be used in pairs

Standard

EN74 Standard / BS1139 / AS/NZS 1576.2

BS1139 Standard / AS 1576

Bolt Spec

Grade 8.8 High-Strength Bolt M16×90 mm (High Clamping Force)

Grade 8.8/4.8 Bolts M14 / M16 × 85 mm

Nut Spec

23mm/24mm Heavy-duty Hex Nut (7/8" / 22.2mm ANSI Standard Optional)

21mm/22mm/23mm Hex Nut

Unit Weight

1.40 kg – 1.50 kg/piece (standard weight 1.45 kg)

1.20 kg – 1.35 kg / piece

Safe Working Load (SWL)

Slip Load: 10.0 kN/pair; Pull-out Load: 30.0 kN/pair

Sliding load: 6.5 - 8.0 kN/pair; Pull-out load: 20.0 kN/pair

Surface Treatment

Electro-Galvanized / HDG

Electro-Galvanized / HDG

MOQ

500 pieces (or 250 pairs)

1,000 pcs

Packaging

15 pieces/carton, 600 pieces/steel pallet

20 pieces/woven bag, 800 pieces/wooden pallet

Top Markets

The United States, Canada, the United Kingdom, Singapore, the United Arab Emirates, and Brazil

Conventional construction projects in Southeast Asia and the Middle East

Critical Safety Warning — Must Be Used in Pairs:

During installation, girder couplers (Gravlock) must be fitted symmetrically in pairs on the opposing flanges of the I-beam to ensure balanced load distribution. Single-sided use is strictly prohibited.

 

Bolt and Nut Specifications by Market:

North American Market (US & Canada): High demand (due to the prevalence of high-rise steel structures); typically specified with 7/8" (22.2 mm) heavy-duty nuts to allow workers to use electric impact wrenches directly during installation.

UK, Middle East, and Singapore: Standard configuration involves M16 high-strength bolts with 23 mm or 24 mm nuts; large-scale oil and gas platform projects mandate a hot-dip galvanized (HDG) finish.

Board Retaining Clamp / BRC Clamp

Summary of Results:

No.

Test Item

Test Method

1

Failure Force

With Reference to EN 74-1:2005


Test Results:
Test Item Test Result
1# 2# 3# 4# 5# 6#
Failure Force(kN) 42.84 38.89 43.60 42.91 40.79 29.8

Detailed Specifications for Board Retaining Clamps

Specifications

Pressed Board Retaining Clamp (BRC)

Forged Heavy-Duty Board Retaining Clamp

Product Name (English)

Pressed Steel Board Retaining Clamp / BRC Clamp

Drop Forged Board Retaining Clamp

Manufacturing Process

Precision Cold Pressing / Stamping

Hot Die-Forged Head + Stamped Plate Assembly

Material

High-quality Q235 Carbon Steel (Thickness ≥3.5–4.0 mm)

High-quality Q235B/Q355B Forged Steel + Steel Plate

Applicable Pipe OD

Ø48.3 mm (Standard 1.9" Scaffolding Pipe)

Ø48.3 mm (Standard 1.9" Scaffolding Pipe)

Applicable Board Thickness

Fits 38 mm – 50 mm Wooden & Standard Metal Boards

Fits 38 mm – 50 mm Wooden & Heavy-Duty Metal Boards

Standards & Certification

BS1139 / EN74

BS1139 / EN74

Clamping Bolt Spec

Square Head Bolt (M10 / M12 × 70 mm)

Square Head / T-Bolt (M12 × 75 mm)

Nut Spec

19 mm / 21 mm (1/2" BSW) Flange Nut

21 mm / 22 mm Hex Nut

Unit Weight Range

0.55 kg – 0.65 kg/pc (Standard: 0.60 kg)

0.68 kg – 0.75 kg/pc

Holding Force

≥1.5 – 2.0 kN (Prevents board uplift and sliding)

≥2.5 kN

Surface Treatment

Electro-Galvanized / Hot-Dip Galvanized (HDG)

Electro-Galvanized / Hot-Dip Galvanized (HDG)

Minimum Order Quantity (MOQ) 

2,000 pcs

1,000 pcs

Packaging

40 pcs/woven bag, 1,500 pcs/steel pallet

30 pcs/woven bag, 1,200 pcs/steel pallet

Top Markets

UK, Sweden, Finland, Norway, Ireland, Australia

UK, Nordic offshore engineering sector, Middle East

Nuts, Bolts and Rivets

The following are the standard parts used in the scaffolding coupler: screw, nut, gasket and other information: 
 
Common Type: T-Bolt, Eye Bolt, Spliting End Bolt. The diameters of the six common scaffolding coupler bolts, the effective length of the bolts and the applicable countries are as follows:
 
CommonType:Hexagon nuts,wing nuts, flange nut.
According to the size of wrenches in different countries, the common scaffolding coupler nut sizes are 19mm, 21mm, 22mm, and 23mm. Among them, 19mm nuts are generally used in scaffolding couplers in Japan, South Korea and some Southeast Asian countries, 21mm nuts are generally used in related scaffolding couplers in the United Kingdom and Commonwealth countries, and 22mm nuts are suitable for scaffolding systems in the United States, Germany and some European countries. , And 23mm nuts are mainly used in Australia.
 

Market/Region

SEA & Middle East

UK & Europe

AU / NZ

USA / Canada

Standard

EN74 / BS1139 / JIS

EN74-1 / BS1139

AS/NZS 1576.2

OSHA / ANSI A10.8

Bolt & Nut Specs

Eye Bolt / T-Bolt + 22mm (M14) Hex Nut

T-Bolt M12/M14 + 21mm (1/2" BSW) Flange Nut

T-Bolt M12/M14 + 23mm Flange Nut

M12/M14 Bolt + 7/8" (22.2mm) Heavy-Duty Hex Nut

Spanner/Tool

22mm Metric Spanner

21mm (7/16" Whitworth) Scaffolding Spanner

23mm Spanner

7/8" Imperial Spanner

Class

Class A / Class B available

Class B (High load-bearing, slip resistance ≥15kN)

Class B equivalent

Heavy-Duty

Common Surface Finish

Electro-Galvanized

Electro-Galvanized (EG) / Hot-Dip Galvanized (HDG)

Hot-Dip Galvanized (HDG) strongly preferred

Electro-Galvanized / Painted

Market Preferences / Pain Points

High emphasis on cost-performance and delivery times; large oil & gas projects in the Middle East mandate EN74 Class B, while standard civil construction favors 22mm nuts.

Class B certification is mandatory for the vast majority; requires EN74 markings and factory traceability codes.

Coastal climate necessitates high corrosion resistance (HDG); 23mm nut size specified (incompatible with the 21mm standard used in the UK/Europe).

Workers are accustomed to using 7/8-inch nuts (US standard) and electric impact wrenches; some projects prefer the use of heavy washers.

Nut Dimensions & Spanner Size

Middle East and Southeast Asia: 22mm (M14) metric hex nuts are widely accepted.

UK and European markets: 21mm (1/2" BSW) flange nuts are strictly used. Scaffolding ratchet spanners carried by workers in Europe are exclusively 21mm.

Australian market: 23mm nuts are the standard. Shipping 21mm or 22mm nuts to Australia by mistake means workers cannot tighten them with their on-site tools, leading to bulk returns.

North American market: Imperial 7/8" (22.2mm) nuts are used.

The bolt diameter and unit width and height of common hexagon nuts are shown in the following table:

Width across flats for hexagon nut, And Using Countries

Width

21

United Kingdom and the Commonwealth of Nations

Width

22

USA, Germany and some Eurupean countries

Width

23

Australia

Width

19

Japan, South Korea and some Southeast Asian countries




 
 

 

Bolt Dia.

Width across flats

Height

Width across flats

Height

Width across flats

Height

Hexagon Nut

1/2"

S21

H11

S22

H11

S23

H11

Hexagon Nut

 

SF21

H14

SF22

H14

SF23

H14

Hexagon Nut

 

SF21

H19

SF22

H19

SF23

H119

Hexagon Nut

 

S21

H15

 

 

 

 

Hexagon Nut

M14

S22

H11

S23

H11

 

 

Hexagon Nut

 

SF22

H14

SF23

H14

 

 

Hexagon Nut

 

SF22

H19

SF23

H119

 

 

Hexagon Nut

M12

SF19

H9

 

 

 

 

Wing Nut

1/2

 

 

 

 

 

 

 

Dia.

Effective length / Bolt length

Use

 

 

T-Bolt

 

1/2

75-88

United Kingdom and the Commonwealth of Nations

M14

75-87

USA, Germany and some Eurupean countries

M14

98-110

USA, Germany and some Eurupean countries

 

 
Eye Bolt

1/2

67-86

United Kingdom and the Commonwealth of Nations
M12 57-73 United Kingdom and the Commonwealth of Nations
M14 70-90 USA, Germany and some Eurupean countries

Spliting End Bolt

1/2

45-82 For Putlog coupler, BRC, etc.

 

Carriage Bolt

 

 

1/2

 
116-125

 

For tube external clamp, universal clamp, etc.

 
85-92

Hexagon Bolt

M16

72-80 For Girder Coupler, DF Joint Pin

Flat T-Bolt

1/2

66-76

For Italian couplers

The thickness and inner/outer diameter of the washer are as follows:

 

Thickness

Inner / Outer Dia.

 

Washer

3.5

13-26

5

13-26

 
 
 
 
You can find different types of scaffolding coupler rivets as follows:

Comparison Dimension

British Style Coupler Rivets

American Style Coupler Rivets

German Style Coupler Rivets

Main Standards

BS1139/EN74-1 Class B

OSHA/ANSI A10.8

DIN4480/EN74-1 Class B

Hinge Pin Diameter

Ø8.0mm (Cold-headed carbon steel)

Ø9.5mm (3/8” design)

Ø8.0mm/Ø8.5mm (Precision hardened steel)

Swivel Pin

Ø16.0mm (Solid hot-forged/cold-headed)

Ø16.0mm/Ø19.0mm (3/4")

Ø16.0mm (Precision ground/with anti-wear washer)

Rivet Head Structure

Flat round flanged head

Large round/heavy thick flange

Precision countersunk/flush rivet head

Material & Treatment

Q235/45# Quenched & Tempered Steel

45# High-strength carbon steel (High impact resistance)

Premium medium-carbon steel (Quenched & tempered; extremely high surface hardness)

Riveting Assembly Process

Hydraulic cold riveting; edge fully filled, no cracks

Pneumatic/mechanical heavy-duty press riveting (High-frequency vibration resistant)

High-precision automated hydraulic press riveting (Tight tolerances)

Galvanizing/Fit Clearance

Standard clearance for electro/hot-dip galvanizing

Larger clearance; suited for rough environments/painted finishes

Precision fit clearance (Typically smooth electro-galvanized finish)

In-depth Breakdown of Key Differences

1. American-Style Rivets — Thick Shafts, Large Flanged Heads, Impact Resistance

Thick Shaft Design: North American construction sites frequently use electric impact wrenches to tighten bolts, generating immense instantaneous torque. Consequently, hinge pins on American-style couplers are often enlarged to 3/8" (approx. 9.5mm), while central swivel pins typically measure 3/4" (approx. 19mm).

Heavy Flanged Head: The riveted head is large and thick, preventing "pull-out" failure caused by the high-frequency vibration and intense tensile forces associated with electric impact tools.

 

2. German-Style Rivets — Precision Engineering, Flush/Countersunk Heads, Smooth Rotation

High-Precision Tolerances: German standards (DIN 4480 / EN74) demand exceptional flatness and fit. Rivet heads are typically flush or semi-countersunk, offering a sleek profile that minimizes the risk of snagging workers' clothing.

Swivel Pins with Anti-Friction Washers: German swivel couplers feature a hardened anti-friction metal washer at the central pivot point connecting the two halves; this ensures structural stability when tightened while providing consistent resistance (damping) during rotation.

 

3. British-Style Rivets — Universal Standards, Corrosion Resistance, Solid & Tough

Classic Ø8mm / Ø16mm Combination: British-style couplers (BS1139) represent the most widely used system globally. They utilize solid rivets with fixed diameters: Ø8.0mm for the cover plate pin and Ø16.0mm for the swivel pin.

Optimized Galvanizing Clearance: Hot-dip galvanizing (HDG) is standard practice in the UK and Commonwealth nations (e.g., Australia, New Zealand). British-style rivets are designed with precise clearance between the rivet and the coupler body hole to accommodate the galvanizing layer, ensuring smooth rotation without binding or excessive play (wobble).

 

Customized Rivet & Pin Solutions for Global Markets:

British / EU Style (BS1139/EN74): Standard Ø8mm hinge pins and Ø16mm solid swivel pins with smooth hydraulic flanged heads.

American Heavy-Duty Style: Upgraded 3/8" (9.5mm) hinge pins and 3/4" (19mm) swivel pins with heavy flange heads to withstand high-torque impact wrenches.

German Precision Style (DIN 4480): High-precision machined pins with flush/countersunk riveting and anti-friction washers for seamless 360° rotation.

UK Drop Forged Scaffolding Coupler Rivet

American Scaffolding Coupler Rivet

UK Pressed Scaffolding Coupler Rivet

German Scaffolding Coupler Rivet

Scaffolding Couplers Types

Right Angle Coupler (Double Coupler, Fixed Coupler). Most used in scaffolding. Swivel Coupler, which is the most flexible of the three common scaffolding couplers. Sleeve Coupler used for the butt joint connection of two scaffolding steel pipes, mainly vertical pipes, horizontal pipes, and diagonal braces.
 

According to British Standard, EN74-1:2005, Scaffolding couplers can be divided into the following four types on the basis of usage scenarios:

 
 
 
Right Angle Coupler: also known as Double Coupler or Fixed Coupler, is usually used to fix pipe vertically and firmly, eliminating the possibility of the steel pipes slipping off. It relies on the friction between the scaffolding coupler and the steel pipe to transfer the load. Such as the connection of the vertical rod and the large crossbar, the large crossbar and the small crossbar of scaffolding.
 
 
Swivel Coupler: Used for cross-connection and fastening of two scaffolding steel pipes at any angle. Connects and fixes two components and can rotate flexibly to facilitate construction.
 
 
Parallel Coupler
 
Parallel Coupler: Used for fixing two parallel scaffolding steel pipes, mainly used for fastening fence.
 
 
 
Sleeve Coupler Sketch is usually used to connect two steel pipes firmly to make them one. Sleeve coupler sketch can make up for the shortcomings of a steel pipe too short.
 
 
 
 
 

According to the requirements and usage scenarios of different countries, scaffold couplers can be divided the following types:

 
 
 
Mainly used for scaffolding systems used in the UK and Commonwealth countries.
 
 
British type:
American type:
 
Mainly used in Scaffolding system of the United States.
 
German type:
 
Mainly used in German scaffolding system.
Italian type:
 
Mainly used for scaffolding systems in Italy.
 
Holland type:
 
Mainly used for scaffolding systems in Holland.
 
Japanese, Korean type:
 
Mainly used for scaffolding systems in Japan & Korea.
 
According to different production processes, there are mainly the following three types:
 
Forged scaffolding couplers:This production process can lead to a result that the toughness of the scaffolding coupler will be guaranteed while ensuring the strength. This is where forged scaffolding coupler is superior to the pressed coupler and casting coupler. Use a high frequency electric furnace to heat the carbon structural steel of the corresponding specification to austenite state at 950&#176;-1050&#176;C, and undergo a one-time forging of 300-600KN to improve its structure and mechanical properties, improve product toughness and protect its strength.
 
 
Pressed couplers:Compared to forged coupler, pressed coupler has a price advantage and especially make up for some products vacancies that cannot be produced by forging process,Use Q235, Q355, SPHC and other grades of steel plates, processed into couplers that meet the requirements of BS EN74-1:2005 through cutting, mold forming, galvanizing, assembly and other processes. Compared with forged scaffolding couplers, it has a certain price advantage, and it also makes up for the production gap that cannot be realized by some scaffolding couplers forging technology. 
 
 
Casting couplers:
Casting couplers:Even casting scaffolding coupler has high hardness its shortcomings of poor toughness that cannot be overcome finally leads to a decline in market share year by year. Heat the copper and iron to a liquid state, pour it into a casting mold, cool it naturally, and then assembleIt has the characteristics of high production efficiency, fast production cycle and low cost. Due to the insurmountable characteristics of castings: high hardness but poor toughness, the market share is declining year by year.
 

1.Hot-dip galvanized couplers: After degreasing, pickling, dipping, and drying, the scaffold couplers are immersed in the molten zinc solution for a certain period of time and then taken out.

2.Electro-galvanized couplers: Electro-galvanized couplers are scaffolding couplers that need to be processed by degreasing and pickling with electrolysis equipment, then put them into a solution of zinc salt, and then connect the negative electrode of the electrolysis equipment; Place a zinc plate on the opposite side of the piece and connect it to the positive electrode of the electrolysis device, turn on the power, and use the directional movement of the current from the positive electrode to the negative electrode to gradually deposit a layer of zinc on the surface of the scaffolding coupler.
3.Hight Protected paint couplers: Spray paint is a coating method that is sprayed through a spray gun or a disc atomizer, dispersed into uniform and fine droplets by means of pressure or centrifugal force, and applied to the surface of the scaffolding coupler.

Scaffolding Couplers manufacture

As high quality scaffolding coupler manufacturer in China, EK Scaffolding has advanced production equipment for forged couplers and pressed couplers,
All forged scaffolding coulpers use high-frequency electric furnace to heat different specifications of structural steel to 950-1050 austenite state, after 4000KN one-time forging can improver its organizational structure and mechanical properties, thereby improving the plasticity and mechanical properties of the product.

Scaffolding Coupler Brochure

Here is brochure of EK scaffolding coupler products. You can see casting and special shaped coupler, pressed coupler, sleeve scaffolding coupler and other realeted scaffold products from this brochure.

Why choose EK Scaffolding Couplers

EK Scaffolding is a China scaffolding manufacturer that started with high quality scaffolding clamps. We have 14 years experience in this scaffold industry. Values of EK Scaffolding are professional service, quality assurance and fast delivery.
world's top coupler brand
World's top OEM coupler factory brand,  forge and press scaffolding coupler all international types
Large delivery
Over 60 containers per month, port of destination customs clearane, home delivery.
Efficient and convenient
L/C, T/T, D/P, forward payment, By Sea, by rail, road transport, Efficient and convenient.
high-grade accessories
All EK scaffolding coupler use high-grade accessories, 8.8-grade high-strength screw.

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