What is Keyway Slotting?
Keyway slotting is a specialist machining process used to cut internal or external keyways, splines and slots into a component — features that cannot be produced by conventional milling or turning alone. A keyway is a precisely machined groove, typically cut into a bore or shaft, that accepts a key: a small metal component that locks a shaft and a hub (such as a gear, pulley or coupling) together so they rotate as one, transmitting drive without slipping.
Our keyway slotting service uses a slotting machine, which employs a reciprocating cutting action — the tool moves in a linear up-and-down motion, removing material incrementally with each stroke. This is fundamentally different from milling or turning, and is the only practical method for producing certain internal features, particularly blind keyways and splines deep within a bore where a milling cutter cannot reach.
At Elmax Engineering Ltd, our keyway slotting capability complements our wider machining services, allowing us to produce complete, fully featured drive components without sending work out to a third party. This keeps lead times short and quality consistent across the whole component.
Keyway slotting is often the final operation on a component that has already been through our CNC machining Manchester process, forming part of our complete Manchester precision engineering service from our Stockport facility.
How Our Keyway Slotting Service Works
Producing an accurate keyway requires careful setup and a controlled cutting process. Here's how our keyway slotting service typically works:
Component Preparation
The component — typically a bore, shaft or hub already produced via our CNC turning services or milled to its main dimensions — is set up and aligned precisely on the slotting machine ahead of cutting.
Tool Setup
A slotting tool matched to the required keyway width is fitted and aligned to the exact position and depth specified on the drawing.
Reciprocating Cutting
The tool moves in a linear reciprocating motion, removing a small amount of material on each stroke and gradually cutting the keyway, slot or spline to the full required depth.
Inspection
The finished keyway is checked for width, depth and position accuracy using calibrated gauges before the component is passed for final inspection and despatch.
Applications of Keyway Slotting
Our keyway slotting service is used to produce a wide range of drive and locating features:
Internal Keyways
Keyways cut into a bore to accept a key that locks a shaft in place — the most common application of keyway slotting, used in gears, pulleys and couplings.
External Keyways
Slots cut along the outside of a shaft to accept a key, allowing a hub or component to be securely fixed and driven without rotating independently.
Splines & Serrations
Multiple narrow grooves cut around a bore or shaft, providing a high-strength drive connection that distributes torque evenly across several engagement points.
Square & Rectangular Slots
Precision square or rectangular internal slots for components requiring a non-standard engagement feature beyond a simple keyway.
Gear & Sprocket Features
Drive features machined into gears, sprockets and pulleys to ensure secure, positive engagement with the shafts they are mounted on.
Coupling Components
Keyways and slots in shaft couplings, ensuring accurate alignment and reliable torque transmission between connected shafts.
Why Choose Elmax Engineering for Keyway Slotting?
Our keyway slotting service is typically combined with our CNC milling service and cylindrical grinding capability to produce complete, fully finished drive components. We serve a wide range of industries across Manchester and the North West — read more on our engineering blog.
Frequently Asked Questions — Keyway Slotting
A keyway is a precisely machined groove that accepts a key — a small metal component that locks a shaft and a hub, gear or pulley together so they rotate as one unit, transmitting drive without slipping. Keyway slotting is the process used to cut these grooves accurately.
Some external keyways can be milled, but many internal keyways — particularly blind keyways deep within a bore — cannot be reached by a milling cutter. Keyway slotting uses a reciprocating cutting tool that can access these internal features, making it the only practical method for many components. Our CNC milling service can produce some slot features directly, but specialist internal keyways are handled by our dedicated slotting capability.
A keyway is a single groove that accepts a separate key component. A spline consists of multiple grooves machined directly into a shaft or bore that mesh with matching grooves on the mating component, distributing torque across several engagement points without a separate key. Our keyway slotting service produces both.
We hold tight positional and dimensional tolerances on width, depth and location, consistent with standard engineering keyway specifications. Where a component requires extremely tight tolerances on the surrounding bore or shaft, our cylindrical grinding service can be used in combination with keyway slotting.
Send your drawings or sample component to Cameron@elmax-engineeringltd.uk or use our contact form, specifying the keyway dimensions and quantity required. You can also call us on 0161 432 8840 to discuss your requirements.
Need Keyway Slotting in Manchester or Stockport?
Get in touch with Elmax Engineering Ltd for precision keyway slotting and complete drive components. CNC turning, milling, grinding and slotting all under one roof.