Description
What Makes This Yoke Different
The Plain Bore Yoke with D-Keyway and Clamp Bolt is a core connection component in modern PTO drive shaft systems. Unlike standard round-bore yokes, the D-shaped keyway profile ensures a precise angular lock between the yoke and the shaft, completely eliminating rotational slip under high-torque cycling. The integrated clamp bolt arrangement adds a secondary mechanical retention force, meaning the assembly stays secure even when the drivetrain is subject to reversal loads, shock inputs, or vibration — conditions commonly encountered on UK farms, construction sites, and industrial processing plants.
Manufactured from high-grade steel with controlled heat treatment, these yokes are designed to work within Ever-Power’s full range of PTO drive shafts — providing British engineers and procurement teams with a dependable, dimensionally accurate component that meets the demanding cycle requirements of European agricultural machinery standards.
Why UK Engineers Specify This Yoke
Zero-Slip D-Keyway Drive
The flat on the D-bore mates directly with the shaft flat, delivering positive torque transmission without relying solely on friction. Combined with the clamp bolt, shaft pull-out under axial load is resisted far more effectively than plain round-bore designs.
High-Grade Steel Construction
Each yoke is forged or machined from alloy steel, then heat-treated to achieve the surface hardness and core toughness required for continuous PTO operation. The result is a part that resists both fatigue cracking and deformation across thousands of operating hours.
Wide Series Range
Available across Series 1 through 8 with bore diameters from 20 mm to 50 mm, this yoke covers the majority of tractor and implement shaft sizes used on UK and European machinery — reducing the need to source multiple components from different suppliers.
Fast UK Dispatch
Stock items ship promptly from our UK-accessible logistics network, with consolidated pallet options for larger orders. Lead times for custom-specified bore sizes and surface treatments are quoted individually and kept as tight as our production schedule allows.
Dimensional Consistency
CNC machining to tight tolerances on the yoke bore, cross-hole, and clamp bolt thread ensures interchangeability across batch deliveries. UK maintenance teams can therefore replace worn yokes without re-alignment or re-drilling — saving valuable downtime during seasonal peaks.
How the D-Keyway & Clamp Bolt System Works
The operating principle of this yoke design is elegantly straightforward, yet mechanically robust enough for continuous agricultural field use. When the yoke is slid onto a D-section shaft, the flat on the bore aligns with the flat on the shaft, providing an immediate anti-rotation keyed interface. The clamp bolt — positioned perpendicular to the bore axis — is then tightened to draw the yoke walls inward around the shaft, generating a clamping force that acts radially around the circumference. This dual-action retention (keyed engagement plus radial clamp) means the assembly handles both torque and axial withdrawal forces simultaneously.
Under field conditions — such as when a tractor PTO engages rapidly, or when a combine’s feeder house reverses to clear a blockage — the yoke must absorb instantaneous torque spikes without micro-slipping. Micro-slip leads to fretting wear, elongated bores, and eventual catastrophic loosening. The D-keyway prevents this by distributing the tangential load over a much larger contact area than a round bore, while the clamp bolt prevents any linear movement along the shaft that could work the key loose over time. It is this combination that distinguishes the plain bore D-keyway clamp bolt yoke from simpler alternatives and justifies its use on higher-torque PTO drive shafts.
Material
Alloy steel with heat treatment (surface hardened, tough core)
Surface Finish
Electrophoretic coating or phosphate + oil (corrosion protection for UK climate)
Drive Interface
D-bore keyway profile + radial clamp bolt for dual retention
Application Temp.
-20 degrees C to +120 degrees C continuous operation
Technical Specification & Dimensional Drawing
Dimensional reference drawing for the Plain Bore Yoke — D-Keyway & Clamp Bolt series:
Note: Dimensions are reference values. Custom bore sizes and special surface treatments available on request. Contact our engineering team for non-standard requirements.
Where This Yoke Is Used — UK Application Scenarios
Across the United Kingdom, the Plain Bore Yoke with D-Keyway and Clamp Bolt turns up in a remarkably wide range of power transmission scenarios. In arable farming, it is the standard connection method on the input end of seed drill PTO drive shafts, where the seasonal start-up loads can be severe and any loosening during a planting run would be costly. On grassland farms in Scotland and the Welsh uplands, the same yoke connects mower-conditioner gearboxes to tractor PTOs — a demanding application given the continuous high-speed running and the risk of sudden impact from hidden stones. Livestock operations use it on feed mixer wagons, slurry pump shafts, and silage blowers throughout England’s dairy belt, from Somerset through to Shropshire and Cheshire.
Beyond agriculture, the yoke appears in small-scale construction and civil engineering — powering compactor plate drives, cable reel drives, and portable generator PTOs on sites across the Midlands and the South East. Industrial applications in food processing — beet washing, potato handling, vegetable conveyors — also rely on this type of yoke where the bore must be kept clean and replacement must be quick. The availability of bore sizes from 20 mm to 50 mm means one product family handles the majority of shaft diameters a UK contractor is likely to encounter.
Arable & Grassland
Farming
Food Processing
Plants
Construction &
Site Equipment
Portable Generator
PTO Drives
Livestock &
Slurry Equipment
Complete PTO Drive Shaft Range
This yoke is compatible with all four series in the Ever-Power PTO drive shaft family. Select the series that matches your torque and operating environment:
Agricultural
PTO Drive Shaft G Series
General-purpose agricultural PTO shaft covering standard tractor implement connections up to medium torque applications on UK farms.
Standard Duty
PTO Drive Shaft S Series
Versatile S Series shaft designed for a broad range of implement types, balancing weight, strength, and cost for everyday field and site operations.
Light Duty
PTO Drive Shaft L Series
Compact and lightweight design for smaller tractors and horticultural machinery — widely specified on market garden equipment and compact utility tractors across the UK.
Heavy Duty
PTO Drive Shaft T Series
Heavy-duty T Series shaft engineered for high-torque applications including large-scale balers, forage harvesters, and industrial PTO-driven machinery requiring maximum power transfer.
Manufacturing Capability & Custom Specification Service
Ever-Power operates a dedicated precision machining facility equipped with multi-axis CNC turning centres, coordinate measuring machines, and full in-process quality control. Every batch of Plain Bore Yokes with D-Keyway and Clamp Bolt goes through dimensional verification against the nominal drawing before dispatch, which is why our UK customers rarely see out-of-spec parts arriving on site. The workshop floor covers forging, rough machining, heat treatment, finish machining, and surface coating — all under one roof — so lead times are genuinely controlled rather than dependent on sub-supplier schedules.
Our product customisation service is one of the strongest differentiators we offer to British distributors and OEM machinery builders. Non-standard bore diameters, alternative keyway profiles, modified clamp bolt positions, special coatings for high-moisture environments, and even bespoke yoke arm dimensions can all be quoted from technical drawings or dimensional specifications. We have produced custom PTO yoke components for UK manufacturers of specialist horticultural equipment, offshore energy maintenance platforms, and custom-build agricultural attachments. If your application falls outside the standard series range shown in the table above, send us a drawing or a sample — our engineering team will assess it within two working days and provide a price and lead time.
Customer Success: Real Results in the Field
Here is how buyers across the UK and Europe are putting these yokes to work in demanding real-world conditions.
🇬🇧 Case Study — East Anglian Arable Contractor, UK
Eliminating Seasonal Yoke Failures on a 3,200-Acre Operation
A large arable contracting business operating across Norfolk and Suffolk was experiencing repeated PTO yoke slippage on their fleet of seed drills during the spring planting window. The bores were wearing oval within a single season, causing shaft run-out and ultimately damaging the drill gearboxes. After switching the entire drill fleet to the Ever-Power Series 5 and 6 Plain Bore Yokes with D-Keyway and Clamp Bolt, the contractor reported zero bore wear failures across the following two planting seasons — covering approximately 6,400 drill-acres. The dual retention system held firm even on the longer daily stints the team was running across the heavy Suffolk clay soils. The maintenance manager noted that the torque-check intervals on the clamp bolts could be extended from weekly to fortnightly without any measurable movement on the shaft flat — a direct result of the D-keyway taking the primary drive load.
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We have been sourcing PTO yokes and shafts from Ever-Power for three seasons. The dimensional accuracy is consistent batch to batch, which matters a great deal when you are replacing components mid-season and cannot afford any fitting issues on a field-side repair.
James H. — Agricultural Machinery Distributor, Lincolnshire, UK
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We supply agricultural spare parts to dealers across Belgium and the Netherlands. The Ever-Power D-keyway clamp bolt yokes have become one of our most reliable product lines — returns are negligible and the range covers virtually every shaft size we encounter in the field.
Marc D. — Agricultural Parts Wholesaler, Ghent, Belgium
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Our workshop handles PTO drivetrain repairs for a large client base in the Yorkshire Dales and North York Moors. We switched to Ever-Power yokes two years ago and the callouts for shaft-slippage faults have dropped significantly. The clamp bolt system is something our technicians trust.
Tom R. — Agricultural Engineering Workshop, North Yorkshire, UK
Frequently Asked Questions
Ready to Source Plain Bore Yokes for Your UK Operation?
Whether you need a standard catalogue item or a custom specification, our team can provide a detailed quote and technical support within one business day.
edit by gzl
