Description
Plain Bore Yoke B-Keyway
Precision-Machined Yoke Fittings for Agricultural & Industrial PTO Drive Shaft Applications
The Plain Bore Yoke B-Keyway is a core connecting component widely used across agricultural machinery, construction equipment, and industrial power transmission systems throughout the United Kingdom and beyond. Designed to mate directly with PTO drive shafts, this yoke features a precision plain bore with a B-type keyway slot, ensuring positive torque transmission without slippage under demanding operating conditions. Whether you are running a heavy-duty tractor-mounted implement on a Scottish farm or driving auxiliary equipment on a factory floor in the English Midlands, the dimensional accuracy and metallurgical consistency of this component directly influence the reliability and service life of the entire driveline assembly. Every unit produced at our facility undergoes strict dimensional inspection and surface treatment verification before dispatch, reflecting our commitment to delivering components that perform exactly as specified, right out of the box.
Why UK Engineers Choose This Yoke
A well-specified plain bore yoke with B-keyway geometry is not simply a commodity part — it is a precision interface between your power source and your implement. The engineering choices behind bore tolerance, keyway profile, and surface hardness determine how reliably torque is transmitted under sustained load, shock loading, and temperature variation. Our yokes are manufactured from medium-carbon or alloy steel billets selected for their homogeneous grain structure, then CNC-machined to achieve bore tolerances consistent with H7 fits. The B-type keyway is broached to DIN 6885 standards, ensuring compatibility with standard keystock across the UK and European supply chain. A controlled heat treatment cycle imparts core toughness alongside a hardened surface, extending fatigue life in repetitive duty cycles.
CNC-Machined Bore Precision
Bore diameters machined to H7 tolerance class, ensuring consistent shaft fit without post-installation adjustment or shimming.
DIN 6885 B-Keyway Profile
Broached keyway conforms to DIN 6885 Part 1 dimensions, compatible with standard parallel keys across UK and EU sourcing channels.
Heat-Treated Alloy Steel
Core toughness with surface hardening resists fatigue crack initiation even under cyclical high-torque loading in agricultural and industrial environments.
Wide Series Range
Eight series groups (1.05 through 8.05) covering bore diameters from 20 mm to 45 mm address a broad spectrum of shaft sizes and torque ratings.
Custom Bore & Keyway Options
Non-standard bore diameters and alternative keyway profiles are available on request, supported by in-house CNC capabilities without minimum order surcharges on tooling.
100% Dimensional Inspection
Every yoke is gauged before shipment. Bore, keyway width, and overall length are verified against drawing tolerances with documented inspection records available on request.
Material, Design Principle & Application Scenarios
The plain bore yoke with B-keyway operates on a straightforward but critical mechanical principle: the parallel key seated in the B-keyway bridges the bore and the shaft, creating a positive interference in the rotational direction. Unlike interference press fits or splined connections, a keyed plain bore yoke can be assembled and disassembled in the field using basic hand tools — a practical advantage for UK agricultural contractors who need to swap implements across multiple tractors during the busy planting or harvesting season. The plain bore itself is left without splines or threading, which simplifies manufacture and allows tight bore-to-shaft concentricity, reducing vibration generation at speed.
Material selection follows a tiered approach based on series load rating. Smaller series (1.05–3.05) are typically produced from C45 medium-carbon steel, providing adequate toughness for light-to-medium agricultural duty. Larger series (5.05–8.05) transition to 40Cr or 42CrMo4 alloy steel, offering higher hardenability and fatigue resistance necessary for continuous-duty industrial PTO applications such as generator sets, industrial mixers, and hydraulic pump drives. All grades are sourced from certified steel mills with full material traceability. Surface treatment consists of phosphate coating or electrophoretic paint depending on the export destination and customer specification, protecting the bore and exterior faces from corrosion during ocean freight to UK distribution warehouses.
Rotavators, slurry pumps, hay balers, and post-hole borers across UK farms and estates.
Hydraulic pump drives, industrial conveyors, and power generation sets in UK manufacturing facilities.
Cement mixers, compactors, and auger drives on UK construction sites where field serviceability is essential.
Direct OEM-dimension replacement for worn or damaged yokes in existing PTO drive shaft assemblies — no shaft modification required.
Technical Specifications
The table below covers all standard series of the Plain Bore Yoke B-Keyway. Dimensions A through F correspond to the engineering drawing. Please refer to the drawing below for dimensional reference when selecting your series.
* All dimensions in millimetres. Tolerance class H7 for bore D. Non-standard dimensions available on request.
Manufacturing Facility & Custom Engineering
Our production facility operates a dedicated PTO component machining line equipped with CNC turning centres, vertical machining centres, and broaching machines capable of handling a full range of bore and keyway geometries. The site runs multi-shift operations with a quality control checkpoint at each stage — incoming material inspection, in-process dimensional gauging, and final inspection before packaging. This level of process control is what allows us to guarantee tight bore tolerances across every batch, whether you are ordering ten units or ten thousand.
Customisation is a core part of what we offer. UK distributors, OEM assemblers, and agricultural machinery manufacturers have different requirements from a standard product catalogue, and we recognise that. Our engineering team can work from customer drawings, sample components, or performance specifications to produce plain bore yokes with non-standard bore diameters, alternative keyway profiles (A, C, or D types), custom flange drilling patterns, or modified overall lengths. Prototype lead times are typically two to three weeks, with production lead times negotiated based on volume and complexity. There are no arbitrary minimum order quantities on custom parts — we are set up to handle both small development runs and high-volume serial production efficiently.
Customer Success: How UK & European Businesses Rely on Our Yokes
Sector: Arable Farming & Contract Machinery Services
A mid-size agricultural contractor based near Harrogate, North Yorkshire, operates a fleet of twelve tractors running rotavators, combination seed drills, and slurry spreading tankers across several thousand acres of arable contract. Over three consecutive seasons, they had been experiencing premature yoke wear on a competing supplier’s components, with bore elongation becoming evident after approximately 400 hours of work on heavier clay soils. After switching to our 4.05B30 and 5.05B35 Plain Bore Yokes, their maintenance engineer reported zero bore deterioration across an equivalent 400-hour period during the following season. The dimensional consistency between batches also meant their workshop could keep a minimal spares inventory rather than stocking yokes from multiple suppliers to cover tolerance variation. Annual procurement spend on yoke replacements dropped by an estimated 30%, and unplanned downtime during the critical spring drilling window was eliminated across the fleet.
“We source plain bore yokes in batches of 200 for our implement repair business in Lincolnshire. The bore dimensions are spot-on every time — we have stopped pre-checking each piece individually because the consistency is that reliable. Lead times to our UK depot have been within the quoted window on every order.”
James R.
Agricultural Parts Distributor, Lincolnshire, UK
“We needed a non-standard bore size for a specialist pump drive application in our processing plant in the West Midlands. The engineering team responded with a detailed proposal within 24 hours, the prototype matched our drawing exactly, and the production run was delivered on schedule. The price was genuinely competitive against standard catalogued parts from UK distributors.”
Maria S.
Procurement Manager, Food Processing Industry, West Midlands, UK
“As a tractor dealer in Scotland we fit a lot of PTO shaft components during pre-delivery preparation and service. These yokes are consistently within tolerance, the surface treatment holds up well through a Scottish winter, and the range covers virtually every shaft size we encounter. Having a single reliable supplier simplifies our whole ordering process considerably.”
Alistair M.
Service Manager, Agricultural Dealership, Aberdeenshire, Scotland
Complete PTO Drive Shaft Solutions
The Plain Bore Yoke B-Keyway is designed to integrate with our full range of PTO drive shaft assemblies. If you are sourcing a complete driveline rather than individual components, our four main series cover the majority of agricultural and industrial applications encountered across the UK market.
PTO Drive Shaft G Series
General-purpose series suited to standard agricultural and light industrial PTO applications, offering a broad torque range in a compact envelope.
PTO Drive Shaft S Series
Heavy-duty series designed for high-torque applications including slurry tankers, soil cultivation machinery, and large-scale harvesting equipment.
PTO Drive Shaft L Series
Extended-length series addressing applications where shaft-to-implement distance exceeds standard configurations — common on four-wheel-drive tractor platforms.
PTO Drive Shaft T Series
Telescopic series with enhanced slide range for implements with significant depth variation during operation, including subsoilers and trailed spreaders.
Frequently Asked Questions
Ready to Source Plain Bore Yokes for Your UK Operation?
Send us your series reference and quantity. Our team responds within one business day with pricing and lead time.
✉ Contact Us: [email protected]
edit by gzl
