Description
WH3 Light-Industrial Cast-Iron Oldham Coupling — Small Machine-Tool and Vacuum-Pump Drive Joint
The WH3 light-industrial Oldham coupling brings the WH family into the duty class of mid-size light-industrial equipment. With 63 N·m rated torque, 18–22 mm bore range, and 7 000 rpm permissible speed, the WH3 is sized for small machine-tool auxiliary drives, vacuum-pump installations, small compressor drives, and the broad population of light-industrial equipment in the 3–6 kW continuous-power band. The size class corresponds directly to the most common light-industrial OEM equipment specifications — substantial enough to handle continuous-duty production loads, light enough to remain cost-economic, and dimensionally compatible with the IEC 60072 standard motor frame outputs that dominate this power class.
For light-industrial OEM equipment designers, the WH3 represents the productive size at the heart of the WH family’s value proposition. The 63 N·m rated torque comfortably accommodates the typical 30–50 N·m continuous-duty demands of small machine-tool spindles, vacuum-pump installations, and compressor drives. The 7 000 rpm permissible speed extends well above typical operating speeds for these applications, providing comfortable margin for inrush events and routine speed-overshoot. And the 1.8 kg coupling mass remains manageable for single-person installation without specialised hoist or handling equipment. The combined specification profile makes the WH3 a strongly competitive choice across the broad population of light-industrial OEM equipment designs.
Specifications
| Parameter | Value |
|---|---|
| Model | WH3 |
| Nominal Torque (Tn) | 63 N·m |
| Permissible Speed (n) | 7 000 rpm |
| Bore Range (d) | 18 – 22 mm |
| Outside Diameter (D) | 68 mm |
| Overall Length (L) | 78 mm |
| Slider Material | Hardened 45-steel HRC 45-55 |
| Hub Material | HT250 cast iron |
| Radial Misalignment (Δy) | 0.6 mm |
| Angular Misalignment (Δα) | 0.5° |
| Axial Misalignment (Δx) | 0.5 mm |
| Mass | 1.8 kg |
| Shaft Engagement | Keyway + setscrew |
| Lubrication | Grease (re-pack annually) |
Materials
HT250 Cast Iron Hubs (Standard)
Hubs are sand-cast in HT250 grey iron with stress-relief annealing before machining. The cast-iron section delivers cost-economic strength with substantial fatigue-life margin against the WH3’s rated torque. For light-marine, light-chemical-process, or other corrosive-ambient applications, QT500-7 ductile-iron hub variant is documented and available — the spheroidal-graphite microstructure provides expanded corrosion resistance and higher fracture toughness for application-specific deployments.
Hardened Steel Slider
Cross-slider is precision-machined from 45-steel medium-carbon bar, induction-hardened on all four wear surfaces to HRC 45–55. Standard catalogue thickness handles steady-state torque with substantial fatigue margin. For applications with frequent reversal duty (small machine-tool spindles with frequent direction-change cycles), 40Cr alloy-steel slider variant with HRC 55 surface is the engineering-preferred upgrade.
Light-Industrial Mounting
H7-reamed hub bore with parallel keyway to GB/T 1096 (DIN 6885 / JIS B 1301). M8 set-screw for axial location. The cast-iron section’s excellent machinability accommodates custom-bore variants without specialised tooling. For vacuum-pump and small-compressor applications requiring expanded mounting reliability, taper-bushed mounting variants are available through engineering review — typically eliminating keyway-shear concerns for installations with frequent start-stop cycles.
Engineering for Small Machine-Tool and Vacuum-Pump Applications
Small machine-tool installations (benchtop CNC mills, small lathes, surface grinders) and vacuum-pump installations (laboratory vacuum, light-industrial process vacuum, small commercial-vacuum applications) share an engineering characteristic that the WH3 is specifically optimised for: substantial continuous-duty torque with occasional shock-load events from start-up inrush or process-disturbance transients. The WH3’s 4× safety factor against rated peak torque accommodates these events without compromising fatigue-endurance margin. The 0.6 mm parallel-misalignment envelope absorbs the realistic motor-and-pump-housing tolerance accumulation. And the cast-iron section’s inherent vibration-damping properties improve the running characteristics of the host equipment in ways that aluminum or steel couplings cannot match.
For vacuum-pump applications specifically, an additional engineering consideration deserves attention. Many vacuum-pump installations operate in environments where lubrication-loss is operationally significant — vacuum-pump oil drift, sealed-system contamination considerations, or chemical-process compatibility requirements. The WH3’s grease-lubricated cross-slider operates in a sealed coupling guard configuration (IP54 with appropriate housing) that prevents grease drift into the host system. Combined with the annual grease-repack schedule, this lubrication-management profile aligns well with vacuum-pump installation requirements.
For broader engineering background on small machine-tool and vacuum-pump coupling specification, see Ever-power’s light-industrial coupling engineering portal.
Industry Applications
⚙️ Small Machine-Tool Auxiliaries
Auxiliary-drive couplings on small CNC machining centres, benchtop CNC equipment, small lathes, and surface-grinders. Vibration damping supports surface-finish accuracy targets.
Vacuum-Pump Installations
Drive couplings on laboratory vacuum pumps, light-industrial process vacuum systems, and small commercial-vacuum installations. IP54 sealed coupling guard prevents lubricant drift into host system.
Small Compressor Drives
Drive couplings on small reciprocating and rotary-vane compressors in light-industrial and commercial-utility installations. Substantial misalignment envelope absorbs compressor-frame tolerance.
️ Light Heat-Exchange Fans
Drive couplings on light commercial heat-exchange fans, small chiller-system condenser fans, and small HVAC auxiliaries. Continuous-duty operation across the seasonal-cycle range.
Small Process-Pump Installations
Drive couplings on small chemical-process pumps, small water-treatment installations, and light-industrial-process pump applications. QT500 hub variant available for chemical-ambient compatibility.
Light-Industrial Retrofit
Replacement-coupling specifications for discontinued small machine-tool, vacuum-pump, and light-industrial equipment couplings. Standard-catalogue dimensions support direct retrofit for substantial population of legacy installations.
Why Choose Ever-power
Quality & Compliance
WH3 production runs under ISO 9001:2015. Cast-iron melt traceability per heat with chemical-composition certification. Documentation pack covers RoHS, REACH, and CE conformity. For light-industrial OEM customers, supplementary documentation supporting ISO 12100 safety-of-machinery integration is available. For small machine-tool OEM customers, ISO 230-1 geometric-accuracy contribution documentation is supplied on request.
Customisation
Catalogue bore range 18–22 mm; custom-bore variants from 16 mm to 25 mm produced under engineering review with 1-week lead time. Imperial-bore variants (3/4″, 7/8″) supported. QT500 ductile-iron hub upgrade for chemical-process and light-marine applications. 40Cr alloy slider for reversal-duty deployments. Taper-bushed mounting via standard locking-assembly families on engineering enquiry.
Aftermarket
WH3 slider plates and 40Cr alloy variants stocked for 1-business-day shipment. 1.8 kg mass per coupling supports air-freight standard. English-speaking engineering desk responds within 24 hours. For light-industrial OEM customers with multi-product portfolios, consolidated supply arrangements covering WH-family and EP6-family specifications can be structured.
Customer Reviews & Case Studies
★★★★★
East Timor — Small Machine-Tool Operator
Used in: Auxiliary-drive coupling on benchtop CNC milling equipment in a furniture-prototype facility.
Feedback: “Specified the WH3 as a cost-economic alternative to the original-OEM precision-coupling spec. Four years of small-batch production duty without any coupling-attributable downtime. Slider-wear inspection during the most recent annual maintenance showed approximately 40 % service-life consumed — clear margin against next major equipment overhaul. Excellent operational specification for our equipment economics.”
★★★★★
Papua New Guinea — Mining-Support Workshop
Used in: Vacuum-pump drive coupling on a mining-support analytical-laboratory installation.
Feedback: “Remote-site location made original-OEM replacement-coupling supply logistically impractical. The WH3 fitted directly into existing mounting envelopes after dimensional-compatibility verification. Three years of continuous laboratory-support duty without performance issues. Sealed coupling-guard configuration has prevented oil drift into the vacuum-pump intake area, eliminating a maintenance concern that had been recurring with the previous coupling specification.”
★★★★☆
Fiji — Tourism-Industry HVAC Service
Used in: Heat-exchange fan drive coupling on hotel-property HVAC systems across multi-property service contract.
Feedback: “Coastal-tropical ambient (high humidity, salt-air exposure) was problematic for our previous standard-coupling specification. Specified the WH3 with QT500 ductile-iron hub upgrade across the service portfolio. Four years of continuous operation across approximately 60 HVAC installations with one slider replacement per system during scheduled annual service. Knock one star only because the QT500 upgrade lead time was 4 weeks rather than standard 1 week — engineering acknowledged this and worked to compress lead time for our subsequent orders. Otherwise outstanding.”
Frequently Asked Questions
Is QT500 ductile-iron hub upgrade worth the cost premium?
For chemical-process, light-marine, coastal-tropical-ambient, and other corrosive-ambient applications, yes — the QT500 ductile-iron hub’s expanded corrosion resistance and superior fracture toughness deliver meaningful service-life extension over the standard HT250 grey-iron specification. For typical light-industrial production-line and machine-tool applications, the standard HT250 specification provides adequate margin without additional cost premium. The cost premium for QT500 is approximately 20 % over standard catalogue specification.
How is the WH3 sealed for vacuum-pump applications?
For vacuum-pump installations requiring grease-isolation from the host vacuum system, the WH3 is supplied within a sealed coupling-guard configuration that achieves IP54 enclosure-class performance. The sealed guard prevents grease vapour drift while allowing thermal-expansion accommodation through breathable membrane vents. This configuration is the engineering-recommended specification for vacuum-pump installations and is documented in the standard installation drawing pack.
What is the documented shock-load tolerance?
The standard WH3 catalogue specification tolerates instantaneous shock loads up to 2× rated torque (126 N·m) without permanent damage. With the QT500 ductile-iron hub upgrade, peak-torque endurance rises to approximately 2.5× rated (158 N·m). For applications with dedicated shock-load duty profiles, please consult engineering for a documented duty-cycle compatibility review.
Can the WH3 be installed for marine or near-shore applications?
For light-marine and near-shore applications (coastal-tropical ambient, salt-air exposure), specify the QT500 ductile-iron hub variant with sealed coupling-guard configuration. With these two upgrades, the WH3 has multi-year service history in tourism-property HVAC installations, coastal water-treatment plants, and similar near-shore deployments. For direct saltwater exposure or open-ocean marine deployments, the larger SL family is the engineering-preferred specification.
Are consolidated WH-and-EP6 supply arrangements available?
Yes. For light-industrial OEM customers with product portfolios spanning the WH cost-economic specification and the EP6 precision specification, consolidated supply arrangements can be structured — single PO, single commercial framework, blended pricing across both family lines. Programme terms are negotiated with sales desk based on annual demand profile across both specifications. Typical lead-time benefits and volume-pricing improvements apply to the consolidated arrangement.
Quote WH3 for Light-Industrial Mid-Size Drives
For small machine-tool auxiliary, vacuum-pump, small compressor, light heat-exchange fan, small process-pump, and light-industrial retrofit applications, the WH3 is Ever-power’s preferred mid-size cost-economic specification of the WH family. Browse the wider WH series catalogue, read about Ever-power’s light-industrial supply capability, or move directly to a B2B enquiry below.