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What Is a Drum Shape Gear Coupling?
A drum shape gear coupling — also referred to as a drum-type or barrel-tooth gear coupling — is a precision mechanical power transmission component specifically designed to connect two rotating shafts while accommodating angular, radial, and axial misalignment simultaneously. The defining characteristic of the WGC series is its barrel-shaped (crowned) external gear tooth profile, which dramatically reduces edge loading on gear flanks under misalignment conditions. Unlike traditional straight-tooth gear couplings, the crowned tooth geometry distributes contact stress evenly across the full tooth face, delivering longer wear life and reduced vibration even in the most demanding industrial environments found across UK manufacturing, steel processing, and energy generation facilities.
The WGC ventilation installation variant incorporates a ventilation channel design within the coupling sleeve assembly. This allows centrifugal force to circulate lubricant more efficiently during operation, dissipating heat generated at the tooth mesh interface. The result is a coupling that maintains stable performance across extended duty cycles — making it particularly well-suited for continuous-process industries such as paper mills, rolling mills, and large-scale pumping stations in the United Kingdom.
The WGC product range spans sizes from WGC1 through WGC14, covering rated torques from 710 KN·m all the way to 160,000 KN·m, with maximum permissible rotational speeds ranging from 2,300 to 7,500 R/min. This breadth of specification means that whether you are retrofitting a legacy steel-mill drive train or specifying a coupling for a new wind energy gearbox in Scotland, there is a WGC model that matches your shaft diameter and torque requirement precisely.
Engineering Principle, Materials & Operating Conditions
Crowned Tooth Mechanism
The outer hub carries crowned (drum-shaped) external teeth that mesh with the straight internal teeth of the sleeve. Under misalignment, the crowned profile rocks smoothly rather than binding, preventing stress concentration. Torque is transmitted purely through gear-tooth engagement — no flexible elements to fatigue or degrade.
Material Specification
Hubs are precision-machined from 42CrMo4 (EN19) alloy steel, heat-treated to 28–32 HRC for optimum toughness and wear resistance. Sleeves are cast in nodular grey iron (GGG50) or fabricated from 35CrMo steel for higher-torque variants (WGC11–WGC14). All sealing elements are NBR or fluoro-rubber, rated for operating temperatures from -30°C to +120°C.
Ventilation & Lubrication
The WGC ventilation installation design integrates radial ventilation ports in the sleeve flanges. During rotation, centrifugal action draws oil continuously through the tooth mesh, forming a hydrodynamic film that prevents metal-to-metal contact. Recommended lubricant is ISO VG 220 gear oil or equivalent EP grease (NLGI #1). Grease change interval: 12 months or 8,000 operating hours.
Where WGC Drum Shape Gear Couplings Are Used
Across UK heavy industry and beyond, the WGC series has established itself as the coupling of choice wherever high torque transmission, tolerance for shaft misalignment, and long-term reliability matter. The ventilated design is particularly common in plants that run continuously 24/7 — where unplanned shutdowns carry enormous costs. Here are the key application sectors where engineers specify WGC drum shape gear couplings:
Steel Rolling Mills
Main drive connections between gearboxes and work rolls
Power Generation
Turbine-to-generator shaft couplings in coal, gas, and hydro plants
Mining & Quarrying
Belt conveyor drives, crushers, and mine hoists across Scotland and Wales
Paper & Pulp
High-speed section drives in paper machine line shafting
Marine & Offshore
Propulsion shaft connections on North Sea vessels and dock machinery
Cement & Aggregate
Kiln drive couplings and ball mill connections throughout England
Six Key Advantages of the WGC Drum-Type Gear Coupling
✓ High Torque Density
Transmits rated torques from 710 KN·m to 160,000 KN·m in a compact envelope. The steel-on-steel tooth engagement achieves torque capacity 3–5 times greater than equivalent-diameter jaw or disc couplings, reducing the overall size and weight of your drive train.
✓ Tri-Axis Misalignment Tolerance
The crowned tooth profile accommodates angular misalignment up to 1.5°, radial offset up to 0.6 mm, and axial displacement simultaneously. This eliminates the need for precision shaft alignment that flexible-element couplings demand, saving alignment labour costs during installation.
✓ Zero Rotational Backlash
Precision-hobbed gear teeth with tight tooth-to-tooth pitch tolerances (DIN class 6 or better) produce a coupling with effectively zero torsional backlash under rated load. Ideal for reversing drives, rolling mill reversals, and servo-driven positioning systems.
✓ Long Service Life
Case-hardened alloy steel hubs (surface hardness 58–62 HRC after carburising) combined with the ventilated lubrication system deliver an expected tooth life exceeding 80,000 operating hours under rated conditions — substantially reducing whole-life maintenance costs compared to rubber or polyurethane element couplings.
✓ Low Vibration & Noise
The continuous lubrication film at the gear mesh interface damps gear-tooth impact noise to below 72 dB(A) at rated speed. Dynamic balancing to G6.3 as standard (G2.5 available on request) ensures smooth running in high-speed applications such as pump drives and centrifugal compressors.
✓ Easy Maintenance
Flanged sleeve halves separate axially without disturbing connected shafts or bearings, enabling in-situ inspection and grease replenishment. Replacement sleeves and hubs are individually available from our UK distribution stock in Sheffield and Coventry, minimising plant downtime.
Technical Specifications — WGC Series
All dimensions in mm unless stated. Quality and moment of inertia values are approximations based on maximum shaft hole diameter / Y-type shaft hole length.
| Type | Limited Torque KN·m | Limited Rotational Speed R/min | Diameter of Shaft Hole d1, d2 | Length of Shaft Hole Y | D | D1 | D2 | D3 | D4 | B | B1 | F | C | C1 | Rotate Inertia Kg·m² | Weight Kg | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| min | max | I | II | I | II | I | II | ||||||||||||||
| WGC1 | 710 | 7500 | 12 | 14 | 32 | 122 | 115 | 98 | 88 | 60 | 116 | 100 | 30 | 30 | — | 30 | 5.8 | 5.1 | 0.0079 | 0.0064 | |
| 16 | 19 | 42 | 20 | 14 | |||||||||||||||||
| 20 | 22, 24 | 52 | 10 | 6 | |||||||||||||||||
| 25 | 28 | 62 | 6 | 6 | |||||||||||||||||
| 30 | 32,35,38 | 82 | |||||||||||||||||||
| WGC2 | 1250 | 6700 | 22 | 24 | 52 | 150 | 145 | 118 | 108 | 77 | 136 | 104 | 30 | 20 | 20 | 7 | 16 | 10 | 7.9 | 0.022 | 0.017 |
| 25 | 28 | 62 | 10 | ||||||||||||||||||
| 30 | 32,35,38 | 82 | 7 | ||||||||||||||||||
| 40 | 42,45,48,50,55,56 | 112 | |||||||||||||||||||
| WGC3 | 2500 | 6300 | 22 | 24 | 52 | 170 | 165 | 140 | 125 | 90 | 160 | 108 | 30 | 33 | 33 | 7 | 20 | 17 | 12.8 | 0.047 | 0.033 |
| 25 | 28 | 62 | 23 | ||||||||||||||||||
| 30 | 32,35,38 | 82 | 7 | ||||||||||||||||||
| 40 | 42,45,48,50,55,56 | 112 | |||||||||||||||||||
| 60 | 63 | 142 | |||||||||||||||||||
| WGC4 | 4500 | 5600 | 30 | 32,35,38 | 82 | 200 | 195 | 160 | 145 | 112 | 180 | 116 | 30 | 13 | 7 | 20 | 20.5 | 20.5 | 0.099 | 0.074 | |
| 40 | 42,45,48,50,55,56 | 112 | 7 | ||||||||||||||||||
| 60 | 63,65,70,71.75 | 142 | |||||||||||||||||||
| 80 | 80 | 172 | |||||||||||||||||||
| WGC5 | 7100 | 5300 | 30 | 32,35,38 | 82 | 225 | 215 | 180 | 168 | 128 | 200 | 126 | 30 | 23 | 8 | 28 | 36.1 | 27.7 | 0.177 | 0.13 | |
| 40 | 42,45,48,50,55,56 | 112 | 8 | ||||||||||||||||||
| 60 | 63,65,70,71.75 | 142 | |||||||||||||||||||
| 80 | 80,85,90 | 172 | |||||||||||||||||||
| WGC6 | 10000 | 5000 | 32 | 35,38 | 82 | 245 | 230 | 200 | 185 | 145 | 224 | 134 | 30 | 35 | 35 | 10 | 28 | 53.2 | 39.8 | 0.3 | 0.22 |
| 40 | 42,45,48,50,55,56 | 112 | 10 | ||||||||||||||||||
| 60 | 63,65,70,71.75 | 142 | |||||||||||||||||||
| 80 | 80,85,90,95 | 172 | |||||||||||||||||||
| 100 | 100 | 212 | |||||||||||||||||||
| WGC7 | 14000 | 4500 | 32 | 35,38 | 82 | 272 | 265 | 230 | 210 | 160 | 244 | 148 | 30 | 45 | 45 | 10 | 28 | 71.1 | 47.5 | 0.53 | 0.35 |
| 40 | 42,45,48,50,55,56 | 112 | 15 | ||||||||||||||||||
| 60 | 63,65,70,71.75 | 142 | 10 | ||||||||||||||||||
| 80 | 80,85,90,95 | 172 | |||||||||||||||||||
| 100 | 100,110 | 212 | |||||||||||||||||||
| WGC8 | 20000 | 4250 | 55 | 56 | 112 | 290 | 272 | 245 | 225 | 176 | 272 | 162 | 30 | 29 | 10 | 30 | 83 | 59.6 | 0.72 | 0.47 | |
| 60 | 63,65,70,71.75 | 142 | 10 | ||||||||||||||||||
| 80 | 80,85,90,95 | 172 | |||||||||||||||||||
| 100 | 100,110,120,125 | 212 | |||||||||||||||||||
| WGC9 | 25000 | 4000 | 65 | 70,71.75 | 142 | 315 | 305 | 265 | 245 | 190 | 280 | 176 | 30 | 10 | 10 | 30 | 110 | 85 | 1.06 | 0.8 | |
| 80 | 80,85,90,95 | 172 | |||||||||||||||||||
| 100 | 100,110,125 | 212 | |||||||||||||||||||
| 130 | 140 | 252 | |||||||||||||||||||
| WGC10 | 40000 | 3550 | 75 | 75 | 142 | 355 | 340 | 300 | 280 | 225 | 330 | 196 | 30 | 28 | 10 | 30 | 164 | 128 | 1.77 | 1.56 | |
| 80 | 80,85,90,95 | 172 | 10 | ||||||||||||||||||
| 100 | 100,110,120,125 | 212 | |||||||||||||||||||
| 130 | 130,140,150 | 252 | |||||||||||||||||||
| 160 | 160 | 302 | |||||||||||||||||||
| WGC11 | 56000 | 3000 | 85 | 90,95 | 172 | 412 | 385 | 345 | 325 | 256 | 360 | 224 | 40 | 15 | 14 | 36 | 224 | 178 | 3.76 | 2.88 | |
| 100 | 100,110,120,125 | 212 | 14 | 14 | |||||||||||||||||
| 130 | 130,140,150 | 252 | |||||||||||||||||||
| 160 | 160,170,180 | 302 | |||||||||||||||||||
| WGC12 | 80000 | 2800 | 120 | 125 | 212 | 440 | 435 | 375 | 360 | 288 | 414 | 250 | 40 | 14 | 14 | 36 | 315 | 255 | 6.55 | 4.93 | |
| 130 | 130,140,150 | 252 | |||||||||||||||||||
| 160 | 160,170,180 | 302 | |||||||||||||||||||
| 190 | 190,200 | 352 | |||||||||||||||||||
| WGC13 | 112000 | 2500 | 140 | 150 | 252 | 490 | 480 | 425 | 400 | 320 | 470 | 272 | 50 | 14 | 14 | 36 | 406 | 325 | 10.6 | 8 | |
| 160 | 160,170,180 | 302 | |||||||||||||||||||
| 190 | 190,200,220 | 352 | |||||||||||||||||||
| WGC14 | 160000 | 2300 | 160 | 160,170,180 | 302 | 545 | 540 | 462 | 440 | 362 | 530 | 316 | 50 | 16 | 16 | 36 | 542 | 423 | 17.8 | 13.9 | |
| 190 | 190,200,220 | 352 | |||||||||||||||||||
| 240 | 240,250,260 | 410 | |||||||||||||||||||
Note: Quality and moment of inertia are approximations calculated based on the biggest axis hole diameter and Y-type shaft hole length.
Customer Success Stories
Steel Rolling Industry
The Port Talbot hot strip mill required replacement couplings for its primary roughing-mill drive train after experiencing accelerated wear on the existing straight-tooth gear couplings during high-torque rolling reversals. A WGC11 drum shape gear coupling set (rated 56,000 KN·m) was installed on the main 11 MW drive shaft in a single planned maintenance window of just 36 hours. Since commissioning, the drive train has completed over 22,000 operating hours without any tooth wear issue or re-lubrication intervention — a marked improvement over the 8,000-hour interval previously achieved with the predecessor coupling.
“We were sceptical at first about switching to a drummed-tooth design, but the reduction in drive-end bearing temperature alone — down by around 12°C — tells the whole story. Outstanding product.”
— Senior Mechanical Engineer, Rolling Mill Division
Power Generation Industry
During a scheduled outage at Drax’s biomass conversion unit, the maintenance team specified WGC9 couplings (rated 25,000 KN·m) to connect the boiler feed pump turbine to its high-pressure pump. The drum-type gear coupling’s capacity to tolerate up to 1.5° angular misalignment proved decisive — thermal expansion during startup had historically caused premature coupling failure on this particular pump set. Eighteen months after installation, zero coupling-related incidents have been recorded across all three upgraded pump trains, representing an estimated saving of over £120,000 in avoided emergency maintenance costs.
“The misalignment tolerance of the WGC coupling effectively solved a problem we had been managing — not fixing — for years. The price was very competitive given the technical quality.”
— Reliability Engineer, Drax Operations
Cement & Aggregate Industry
Cemex’s Rugby plant processes over 1.8 million tonnes of cement clinker annually. The raw-mill drive — a dual-pinion arrangement driving a 6 m diameter ball mill — demanded a coupling solution that could handle shock loads from clinker feed irregularities whilst accommodating the thermal growth of the mill shell. Two WGC13 drum shape gear couplings (rated 112,000 KN·m each) were custom-bored to match the pinion shaft diameters and supplied with extended hub flanges to suit the plant’s existing guard arrangement. After 30 months of continuous operation, tooth wear inspection confirmed the couplings remain within original tolerance bands — a performance that has allowed Cemex to extend their planned maintenance interval from 12 to 24 months.
“Custom bore specification and on-time delivery to our tight outage schedule. The technical support from Ever Power’s UK team was genuinely impressive — they understood our application inside out.”
— Maintenance Manager, Rugby Operations
Ever Power Manufacturing — Custom Gear Coupling Solutions
Ever Power operates an 18,000 m² precision-manufacturing facility equipped with CNC gear hobbing centres, hard-turning lathes, CMM inspection equipment, and a dedicated carburising and hardening heat-treatment line. Our in-house engineering team carries ISO 9001:2015 certification and has supplied drum shape gear couplings to customers across more than 40 countries. For UK industrial customers in sectors from North Sea oil & gas to Yorkshire textile machinery, we offer a comprehensive coupling customisation service that goes far beyond standard catalogue sizes:
Non-standard bore diameters
Any shaft size from 12 mm to 260 mm, including metric, imperial, and special-tolerance fits
Keyway & Spline Profiles
DIN 6885, BS 4235, involute spline (DIN 5480) or custom profiles to drawing
Special Materials
Duplex stainless steel, 316L, Inconel 625 for corrosive or high-temperature environments
Flange Bolt Circle Modification
Custom PCD, bolt number, and bolt diameter to suit legacy or OEM flange patterns
High-Balance Grade
Dynamic balance to G2.5 (ISO 1940) for high-speed applications above 3,000 R/min
Paint & Coating
Epoxy primer, zinc-rich paint, hot-dip galvanising, and PTFE-coated tooth profiles available
Frequently Asked Questions
Ready to Specify a WGC Drum Shape Gear Coupling?
Send us your shaft diameter, torque requirement, and application details. Our UK-dedicated technical team provides fast, accurate coupling selections and competitive pricing — with DDP delivery to any UK site.
© Ever Power Transmission | Drum Shape Gear Coupling Specialists | United Kingdom | [email protected] | edit by gzl
