Description
21 Standard Sizes
Custom Fabrication Available
Up to 710 kN·m Torque
What Makes the SWC-BH Universal Joint Coupling Different
The SWC-BH standard flex welding type universal joint coupling is a Cardan-principle shaft coupling designed specifically for industrial drive lines where angular misalignment, axial shaft movement, and shock torque loading all occur simultaneously — conditions that defeat simpler coupling designs within months. The coupling’s welded yoke configuration permanently joins each yoke body to the drive shaft tube rather than relying on a bolted flange interface, producing a homogeneous load path that distributes stress evenly across the weld zone rather than concentrating it at bolt holes. This seemingly small construction difference has a pronounced effect on fatigue life in applications such as rolling mill drives, crusher main shafts, and propulsion trains where torque reversal and vibration are continuous.
The range spans 21 model sizes from the SWC58BH — at 58 mm gyration diameter and 0.15 kN·m nominal torque — through to the SWC550BH at 550 mm diameter and 710 kN·m. Mid-range models such as the SWC160BH to SWC315BH cover the majority of industrial gearbox output and pump drive applications encountered by UK engineers, while the upper sizes supply the torque density demanded by steel mill roughing stands and large marine propulsion systems. Every size in the series incorporates a telescoping spline section providing controlled axial float, allowing shaft thermal growth and end-play to be absorbed without loading adjacent bearings. The entire series is available in standard catalogue dimensions, with custom bore geometry, shaft tube diameter modifications, and non-standard flange configurations offered as a routine manufacturing service.
Complete Size Range — SWC-BH Series Specifications
All standard sizes listed below. For non-catalogue bore diameters or modified flange geometry, contact our technical sales team directly.
| Model | D (mm) | Tn (kN·m) | Tf (kN·m) | β max (°) | Ls (mm) | Lmin (mm) | D1 (mm) | Wt (kg) |
|---|---|---|---|---|---|---|---|---|
| SWC58BH | 58 | 0.15 | 0.075 | ≤22 | 35 | 325 | 47 | 2.2 |
| SWC90BH | 90 | 1 | 0.5 | ≤22 | 45 | 435 | 74.5 | 6.6 |
| SWC120BH | 120 | 2.5 | 1.25 | ≤25 | 80 | 485 | 102 | 10.8 |
| SWC160BH | 160 | 10 | 5 | ≤25 | 80 | 660 | 137 | 68 |
| SWC200BH | 200 | 32 | 16 | ≤15 | 110 | 860 | 170 | 86 |
| SWC250BH | 250 | 63 | 31.5 | ≤15 | 140 | 1035 | 218 | 172 |
| SWC285BH | 285 | 90 | 45 | ≤15 | 140 | 1190 | 245 | 263 |
| SWC315BH | 315 | 125 | 63 | ≤15 | 140 | 1315 | 280 | 382 |
| SWC390BH | 390 | 250 | 125 | ≤15 | 170 | 1590 | 345 | 738 |
| SWC440BH | 440 | 355 | 180 | ≤15 | 190 | 1875 | 390 | 1190 |
| SWC490BH | 490 | 500 | 250 | ≤15 | 190 | 1985 | 435 | 1452 |
| SWC550BH | 550 | 710 | 355 | ≤15 | 240 | 2300 | 492 | 2380 |
Tn = Nominal torque · Tf = Fatigue torque · β = Max angular fold · Ls = Axial float travel · Lmin = Minimum assembly length · D1 = Flange dia · Complete 21-size range available.
Four Engineering Advantages That Drive Long Service Life
Full-Penetration Weld Joint
The yoke is welded directly to the shaft tube rather than clamped or bolted, creating a joint where the steel is continuous across the connection boundary. This eliminates fretting corrosion and bolt-interface micro-movement — the two failure modes that shorten bolted coupling life in applications subject to cyclic torque reversals such as roll table drives and reciprocating compressor trains. UK maintenance engineers who have made the switch from flanged alternatives routinely report service intervals extending by a factor of two or more.
Built-In Axial Float Compensation
Every SWC-BH universal joint coupling contains a precision splined sliding section that passively absorbs shaft thermal expansion and gearbox end-play. When a power plant drive heats from ambient to operating temperature, the shaft grows in length — without controlled float, this force transfers directly into thrust bearings, shortening their life dramatically. The axial float values in the SWC-BH series (35 mm to 240 mm depending on size) are calculated to match typical industrial drive-line thermal and dynamic requirements rather than being nominal figures.
High Angular Misalignment Capacity
Smaller SWC-BH models tolerate angular misalignment up to 25°, while larger torque-range units handle up to 15° continuously under full load. These figures comfortably exceed the capabilities of disc, diaphragm, or elastomeric jaw couplings, making the SWC-BH the rational choice for mobile plant, off-road machinery, and any drive train where shaft alignment cannot be maintained precisely over the service interval. Mining equipment operating in northern England’s quarrying regions routinely relies on this misalignment tolerance to survive ground-induced deflections.
Forged Steel Throughout, Needle-Roller Bearings
Unlike cast-yoke designs, the SWC-BH uses forged alloy steel bodies that develop directional grain structure aligned with loading direction during manufacture. Needle-roller bearing cups at each trunnion — rather than plain bronze bushings — provide the low articulation friction needed to prevent heat generation at the cross journal. The result is a coupling that generates minimal heat even at elevated operating angles, an important characteristic in sealed drive lines where grease heat-up causes lubricant degradation and premature bearing failure.
Material Specification, Working Principle & Application Scenarios
The SWC-BH operates on the double-Cardan universal joint principle: two yokes connected by a cross-journal assembly transmit rotary motion through a range of operating angles while maintaining near-constant angular velocity at the driven shaft. Precision needle-roller cups seated in the trunnion bores of the cross journal carry the load, distributing contact stress over a large number of small-diameter rolling elements. The spline sleeve connecting the two yoke assemblies slides freely under axial load while transmitting full torque through spline flanks. Sealing at both the spline interface and bearing cups is provided by NBR lip seals, with high-temperature fluorocarbon seal options available for process-heat environments.
Material selection is driven by fatigue performance rather than cost minimisation. Yoke bodies and the cross journal are produced from 42CrMo4 (EN 1.7225) alloy steel, forged and then quenched and tempered to a core tensile strength in the range of 900–1100 MPa. This gives adequate toughness to survive shock loading without brittle fracture, combined with the tensile strength needed to resist bending loads at the cross-journal trunnion roots — the location where universal joint cross failure most commonly initiates in competitive designs. Surface hardening of trunnion journals by induction heating is applied to the standard range to improve contact fatigue life at the bearing raceway.
From the Field — Three UK Customer Deployments
These accounts represent the kind of drive-line challenges UK engineers bring to us and the outcomes they achieved with the SWC-BH series.
Roughing Mill Roll Table — Replacing Worn Gear Couplings Every 14 Months
A steel plate mill in South Wales had been running gear-type couplings on their No. 2 roughing mill table for years, accepting replacement as a fixed maintenance cost. The primary failure mode was gear-tooth pitting caused by the angular deflection of the roll pass geometry — deflection that the gear coupling could absorb only through tooth sliding, which wore rapidly under the combination of high torque and misalignment. Switching to SWC-285BH universal joint couplings with weld-end configuration eliminated the tooth-contact mechanism entirely. The first set completed 34 months of service before scheduled inspection revealed minor needle-bearing wear — no unscheduled stops occurred in that period.
“We used to plan a coupling change into every major mill shutdown. Two and a half years in, the SWC-BHs look like they might see a third shutdown before they need attention. That changes how we budget maintenance considerably.”
— Lead Mechanical Engineer, Plate Rolling Division, South Wales
Jaw Crusher Main Drive — Chronic Coupling Misalignment Failures
A Derbyshire limestone quarry operation was experiencing coupling failures on the main drive shaft of their primary jaw crusher approximately every eight to ten months. Detailed inspection traced the root cause to foundation settlement creating a persistent angular misalignment of approximately 9° between the motor and flywheel shaft centrelines. Rather than undergoing repeated costly foundation remediation, the site engineering team specified SWC-225BH flex welding type universal joint couplings rated for continuous operation at up to 15° deflection. The coupling cost was recovered within the first avoided repair, and the installation has since operated for over two years without drive-related intervention.
“Foundation repair was going to take the crusher offline for three weeks. Fitting the SWC-BH took one shift and solved the same problem. The engineering logic was obvious in hindsight — we should have done it sooner.”
— Site Engineering Manager, Limestone Quarrying Operation, Peak District
Anchor Handling Vessel Stern Thruster Drive — OEM Replacement Discontinued
An Aberdeen-based offshore vessel management company needed replacement intermediate shaft couplings for the stern thruster drive trains of two anchor-handling vessels. The original OEM coupling was no longer manufactured, and the only alternative quotes were coming back at 18-week lead times. HZPT supplied custom SWC-350BH couplings with modified yoke bores to match the existing shaft ends, complete with material certificates and dimensional inspection records, within five weeks. Both vessels completed their subsequent Lloyd’s class renewals with zero drive-line defects noted, allowing continued offshore operations without the extended yard time an 18-week lead time would have forced.
“Five weeks for a custom coupling with full documentation was frankly better than we expected. The dimensional fit was spot-on and the class surveyor had no comments on the material records. A genuinely seamless replacement process.”
— Fleet Technical Superintendent, Offshore Vessel Operations, Aberdeen
Manufacturing Process — From Forging to Final Assembly
Forging blank → tempering → semi-precision turning → through-hole drilling → tapered bore preparation → fine turning with grinding allowance → cylindrical grinding to final size → thread processing after assembly.
Custom SWC-BH Couplings — HZPT Factory & Engineering Services
HZPT’s manufacturing plant operates forging presses, multi-axis CNC turning and milling centres, gear-grinding machines, CMM dimensional verification, and controlled-atmosphere heat treatment — all within a single facility dedicated to precision coupling production. This integrated capability means that non-standard configurations pass through the same quality chain as catalogue items rather than being subcontracted. For UK industrial buyers, this translates to faster engineering response, shorter quotes, and reliable delivery on modified parts. The factory has supplied custom SWC-BH flex welding type universal joint couplings with alternate yoke bore configurations, modified flange bolt-circle diameters, extended axial float travel, and surface treatments including hot-dip galvanising and phosphate coating, all within standard commercial lead times.
Our 18-year accumulated engineering database covers coupling behaviour across steel, mining, marine, paper, and heavy power generation industries, enabling our technical team to assess replacement and upgrade requirements rapidly, propose the correct model with confidence, and identify where a standard size will serve versus where a custom configuration is genuinely needed. For UK OEM procurement teams and MRO buyers managing discontinued part numbers, we operate a reverse-engineering service that produces fully dimensional replacements from sample parts or engineering sketches, with material and heat-treatment certification supplied as standard. Blanket order agreements with phased delivery are available for customers who need predictable stock availability across a maintenance season without carrying inventory themselves.
Questions UK Buyers Ask Most Often
What is the cost of an SWC-BH standard flex welding type universal joint coupling supplied to a UK address, and how do I request a price from your sales team?
Pricing varies by model number, quantity ordered, and whether any custom fabrication is required. For standard catalogue sizes — SWC58BH through SWC550BH — we return a CIF UK-port quotation typically within one working day. For custom bore or flange configurations, detailed pricing usually follows within 48 to 72 hours after our technical team reviews the requirements. Email your model reference, required quantity, and any dimensional modifications to [email protected] and we will respond promptly.
How do I select the correct SWC-BH universal coupling size for a quarrying conveyor drive in northern England rated at 50 kN·m with shaft misalignment of around 10 degrees?
For 50 kN·m nominal torque and 10° angular misalignment, the SWC250BH (Tn = 63 kN·m, β ≤ 15°) provides adequate torque margin at a service factor above 1.25 and handles your misalignment angle within its rated envelope. If the drive sees regular blocked-material shock loads — common on conveyor head drums — stepping up to the SWC285BH (Tn = 90 kN·m) is advisable. Share your operating data and our engineering team will confirm selection in writing.
Where can a UK marine engineering firm source a replacement SWC-BH flex welding type universal coupling at short notice when the original OEM part number has been discontinued?
HZPT supplies custom-dimensioned SWC-BH universal joint couplings as a standard service. For discontinued OEM references, we work from sample parts, dimensional sketches, or original drawings to produce replacements with matching bore diameters, shaft tube sizes, and flange configurations. Custom units ship within three to six weeks with full dimensional and material certification. UK marine engineering contractors serving Aberdeen, Tyneside, and Southampton yards use this route regularly for vessel repair and refit projects. Contact [email protected] with your measurement data to start the process.
When should a UK power station rotating equipment engineer choose the SWC-BH weld-end coupling over a standard bolted flange coupling for a boiler feed pump drive?
The weld-end configuration should be chosen whenever the coupling is expected to operate for extended intervals — 18 months or more — without disassembly, or wherever shaft alignment cannot be guaranteed to remain within the angular tolerance of a diaphragm or elastomeric coupling over the service period. In boiler feed pump drives, thermal cycling causes shaft centreline shift that accumulates over time; the SWC-BH accommodates this passively through its axial float and angular capacity rather than transmitting the resulting forces into pump or motor bearings. For drives running two-shift cycles in power generation duty, the all-steel SWC-BH also eliminates the temperature-related degradation that affects elastomeric disc elements.
Which lubrication and maintenance schedule is recommended for an SWC-BH universal joint coupling installed on a marine thruster drive in a UK North Sea offshore environment?
For North Sea offshore environments — characterised by persistent salt spray, vibration, and temperature cycling — we recommend re-greasing the needle-roller bearing cups with an EP2 marine-grade lithium-complex grease every 500 to 750 operating hours, coinciding with planned maintenance dives or dry-dock intervals where possible. NBR seals should be visually inspected for lip wear or cracking at each greasing event. For vessels operating in continuous water-spray conditions or high-humidity enclosed spaces, fluorocarbon (FKM) seal upgrades are available and substantially extend seal service life. The spline section should receive a fresh application of EP grease on assembly and at any overhaul where the sliding section is disassembled.
What are the lead times and delivery options for bulk orders of SWC-BH flex welding type universal couplings shipped to UK industrial buyers from your manufacturing facility?
Standard catalogue sizes in common mid-range models (SWC160BH to SWC315BH) are typically held or rapidly produced and ship within two to four weeks for UK-destined orders. Custom-configuration units require three to six weeks from drawing approval. Delivery to UK port of entry is offered on CIF terms; ex-works pricing is also available for buyers with established UK freight arrangements. For MRO buyers managing seasonal maintenance windows, we offer blanket purchase agreements where a confirmed annual quantity is allocated to a rolling delivery schedule, providing price certainty and stock availability without the buyer holding inventory. Volume pricing tiers are available from the first full pallet quantity upwards.
UK B2B Industrial Supply
Specify the Right SWC-BH Universal Joint Coupling Today
Tell us your shaft diameter, required torque, operating misalignment angle, and application environment. We will identify the correct model, confirm pricing for UK delivery, and advise on any custom modifications — with no obligation and a typical response within one working day.
edit by gzl
