Description
EP6-50 Set Screw Oldham Coupling — 50 mm Heavy-Duty Three-Piece Slider for Industrial Pump and Mixer Drives
The EP6-50 Oldham coupling is the heavy-duty member of the EP6 set-screw range. A 50 mm outside diameter, 38 mm overall length, six catalogue bores from 14 mm through 20 mm, and a torque envelope reaching 19 N·m rated / 38 N·m peak at 3 000 rpm place this coupling in the duty class of mid-range industrial pumps, agitator drives, mixer reduction outputs, and large-format packaging-line carriages. It is the workhorse of the EP6 family for production plants that demand a flexible coupling that can absorb realistic frame-fabrication misalignment without becoming a maintenance item.
Distinct from the smaller couplings in the family, the EP6-50 introduces a second design choice: at this size and torque level, customers regularly weigh the EP6-50 against double-Oldham (tandem) configurations and against larger metallic-disc couplings. The EP6-50 wins on three counts: lower reflected inertia at the motor, simpler installation (no flexible disc-pack timing requirement), and substantially better tolerance for thermal growth between motor and load — a factor that often catches engineers by surprise when running plant cycles span a 30 °C ambient swing.
Specifications
| Parameter | Value |
|---|---|
| Model | EP6-50 |
| Outside Diameter (ΦD) | 50 mm |
| Overall Length (L) | 38 mm |
| Bore Range (d1 / d2) | 14, 15, 16, 18, 19, 20 mm |
| Rated Torque | 19 N·m |
| Maximum Torque | 38 N·m |
| Maximum Rotational Speed | 3 000 rpm |
| Moment of Inertia | 6.0 × 10⁻⁵ kg·m² |
| Static Torsional Stiffness | 780 N·m/rad |
| Parallel Misalignment | 3.3 mm |
| Angular Misalignment | 3.0° |
| Set-screw Thread | M8 |
| Wrench Tightening Torque | 15 N·m |
| Mass (max bore) | 144 g |
| Backlash | Zero |
Materials
Hard-Anodised Aluminum Hubs
Hubs are CNC-turned from A6061-T6 and hard-anodised to a 50 µm coating thickness — a step up from the decorative anodise on smaller EP6 sizes. The harder surface protects the slot walls against the small but cumulative wear that the polymer slider can produce over years of high-cycle service. Hub mass is held below 60 g per side to keep reflected inertia in check.
PEEK / GF-POM Slider Options
Catalogue slider is 15 % glass-fibre POM-H, the same compound used on the EP6-40. For applications above 100 °C continuous, or where chemical attack from cleaning agents is expected, a virgin PEEK slider is offered as a documented upgrade — extending the temperature ceiling to +260 °C and dramatically improving solvent resistance.
M8 Set Screws — Two per Hub
Two M8 stainless cup-point set screws per hub, separated by 90°. The 15 N·m wrench torque specification provides enough pre-load to lock against the 38 N·m peak torque rating. Set-screw seating in 6061-T6 aluminum holds up well to repeated service cycles, with no thread-stripping reported across more than a decade of fleet data.
Why an Oldham Coupling at This Power Level
At 19 N·m and 3 000 rpm — roughly 6 kW continuous transmitted mechanical power — the engineer choosing a flexible coupling typically considers four families: jaw / spider, beam, bellows, and Oldham. The EP6-50 wins selection battles in this duty class for a specific reason: it is the only architecture that combines positive zero backlash with a generous (3.3 mm) parallel-misalignment tolerance. Jaw couplings at this size deliver one or two millimetres of parallel offset, but with measurable lash. Bellows and beam couplings deliver zero lash but at most 0.5 mm offset before fatigue cycles become a service-life concern.
The EP6-50’s three-piece slider geometry means that the misalignment is absorbed as sliding friction in two orthogonal interfaces, not as elastic flexure of metal. Service life is therefore determined by polymer wear, not by metal fatigue — and polymer wear is forgiving, predictable, and easy to inspect. The end result, on a real production line, is a coupling that survives 24/7 duty for years between centre-disc replacements, with no degradation of the angular transmission accuracy that the host servo system depends on.
Industry Applications
Industrial Mixer Drives
Coupling between gear reducer output and impeller shaft on chemical-process mixers, paint blenders, and adhesive compounders. Tolerates the thermal growth between cold-start and operating temperatures.
⛽ Fluid Pump Trains
Centrifugal, gear, and lobe pumps in process plants. The EP6-50 acts as a thermal-growth tolerance buffer between electric motor and pump suction housing.
Large-Format Packaging Lines
Pallet wrapping, case-erecting, and palletiser drives. POM slider absorbs the impact loads when a stack hits the gate stop.
Grain & Bulk-Material Augers
Coupling between drive motor and screw-auger input on grain conveyors, silo unloaders, and feed mills. Misalignment tolerance forgives the long, lightly-supported shaft installations typical of agricultural sites.
Bottle-Cap Torque Machines
Tightening-spindle drives on rotary capping machines. The 38 N·m peak torque envelope handles capping-head torque-up profiles without coupling slip.
♻️ Recycling & Sorting Lines
Drum-screen, magnetic-separator, and air-classifier drives. The coupling tolerates the misalignment introduced by frame flex under heavy material loads.
Why Choose Ever-power
Quality & Compliance
Ever-power’s ISO 9001:2015 production system covers the EP6-50 from raw-material receipt to outbound logistics. RoHS, REACH, and CE conformity documentation are available with each order. For pharmaceutical and food applications, supplementary FDA 21 CFR 177.2470 material certification covers the POM slider grade.
Customisation
Beyond the catalogue bore set (14 / 15 / 16 / 18 / 19 / 20 mm), Ever-power machines mixed-bore EP6-50 units, keyway-broached bores, stainless hub variants, and special slider materials including PEEK, PTFE-filled POM, and FDA-direct-contact PEEK. Logo etching on the hub is offered as a private-label option for OEM resale.
Aftermarket Support
Spare centre discs for the EP6-50 are stocked separately and ship in two business days. For fleet operators, our engineering desk can provide a customer-specific service-interval estimate based on duty profile, operating temperature, and parallel-offset history. 24-hour technical response is standard.
Customer Reviews & Case Studies
★★★★★
India — Specialty Chemical Plant
Used in: Agitator drive train on a 5 m³ jacketed reactor running continuous 18-hour batch cycles.
Feedback: “Plant temperature cycles between 22 °C overnight and 48 °C peak during summer afternoons. The 3.3 mm parallel allowance absorbs the resulting thermal growth between motor mount and reactor support, where our previous gear-coupling had been wearing premature. EP6-50 has been in service 27 months without intervention.”
★★★★★
Turkey — Bottle Capping Machine OEM
Used in: Capping-spindle drive on a 36-head rotary capper for olive-oil bottles.
Feedback: “The 38 N·m peak envelope easily handles our 28 N·m capping torque-up. Constant-velocity output ensures uniform cap-on-bottle torque across all 36 heads — a measurable improvement over the jaw couplings we used on the previous machine generation. We have standardised on the EP6-50 across our capping-machine line.”
★★★★☆
Vietnam — Grain Handling Integrator
Used in: Auger drive on a 30 t/h rice-mill conveyor.
Feedback: “Long auger shafts deflect noticeably under load — the 3.3 mm offset tolerance kept our motor bearings out of the warranty-claim column. Knock one star only because we wish for an inch-bore variant for our older US-built motors; engineering did supply this as a custom item but it added two weeks lead time.”
Frequently Asked Questions
What is the recommended service-life replacement interval for the slider?
For an EP6-50 operating at 70 % rated load, 60 % of rated speed, with parallel offset below 1.5 mm, expected slider life exceeds 6 years of continuous-duty service. Replacement-only of the slider — without removing hubs from shafts — is a 10-minute operation. Full-coupling replacement is rarely necessary.
Can the EP6-50 be balanced for high-speed operation?
Standard production balancing meets ISO 1940 G6.3 grade up to the catalogue 3 000 rpm. For operation above 3 000 rpm in special applications, ISO 1940 G2.5 balance is available — please specify “G2.5 balance” at order entry.
How does the EP6-50 handle frequent direction reversals?
The slider geometry is symmetric — CW and CCW transmission characteristics are mechanically identical. Reversal endurance has been validated to over 10 million cycles at rated load in customer reliability testing. The lack of an elastic restoring element means there is no fatigue accumulation in reversal duty.
What axial play does the EP6-50 accommodate?
The slider geometry tolerates approximately ±0.5 mm of axial shaft displacement without slot bottom-out. For larger axial growth — common in long shaft installations — please specify an axial-extension variant.
Are bulk discount terms available?
Yes. EP6-50 carries a tiered volume-discount structure starting at 25 pieces and reaching its maximum at 500 pieces. For annual MRP commitments, fixed-price supply agreements can be negotiated. Contact our sales desk with the projected annual volume for a tailored offer.
Ready to Quote the EP6-50?
From single-piece replacements for existing fleet equipment to volume MRP supply of new-build production lines, the EP6-50 is one of Ever-power’s flagship industrial-duty Oldham couplings. Explore the rest of our flexible coupling product family, learn about our production scale and supply commitments, or proceed directly to a B2B enquiry below.
