Radial In-Feed
The cutting head feeds radially into a shaft or internal bore to establish keyway depth.
Mills / Keyseat cutters
Keyseat Cutters
What Are Keyseat Cutters and How Do They Work?
A keyseat cutter, often called a Woodruff keyway cutter, mills narrow slots, keyseats, and retaining-ring grooves in shafts and bore housings. Its circular cutting head and reduced-diameter shank provide radial cutting access and neck clearance.
Side-Face Shearing
Ground peripheral teeth cut parallel slot walls for controlled drive-key fit.
Neck Clearance
The reduced neck provides clearance between the cutter and adjacent shaft shoulders.
Staggered-Tooth Option
Alternating right- and left-hand tooth geometry can improve shearing action and chip clearance.
Key Features and Benefits of Keyseat Cutters
Standard Woodruff Sizing
Available in standard ANSI Woodruff dimensions for matching specified key sizes.
Side-Milling Rigidity
Solid construction limits tool deflection during radial in-feed passes.
Staggered-Tooth Availability
Staggered flutes can break chips, suppress chatter, and improve surface finish.
Controlled Wall Transitions
Precision-ground tooth margins support clean keyseat edges and accurate key fit.
Multi-Material Capability
Available tool materials and coatings support alloy steel, stainless steel, cast iron, brass, and aluminum.
Keyseat Cutters Specifications
| Specification | Range / Details |
|---|---|
| Cutter Diameter Range | 1/4" to 1-1/2"+; standard ANSI Woodruff sizes 202 to 1212 |
| Cutter Width Range | 1/16" to 3/8"+; metric 1.5 mm to 10 mm+ available |
| Tooth Styles | Straight tooth or staggered tooth with alternate helix |
| Flute Count | 6 to 16+ peripheral teeth, varying by head diameter |
| Shank Style | Straight cylindrical or Weldon flat shank |
| Operation Type | Keyseat milling, Woodruff slotting, and snap-ring grooving |
Materials and Coatings Available for Keyseat Cutters
| Material / Coating | Best For | Key Advantage |
|---|---|---|
| Solid Carbide | Hardened steels, stainless steel, and high-volume production. | High rigidity limits tool flex and supports controlled keyway width. |
| HSS / HSS-Co | Interrupted cuts, manual machines, and low-volume repair. | Impact toughness helps resist tooth chipping in manual shaft-slotting operations. |
| TiAlN / AlTiN Coating | Tough alloy steels, cast iron, and dry milling. | Thermal hardness helps protect peripheral teeth from friction-related wear. |
Solid carbide provides rigidity for production work, HSS or HSS-Co provides impact toughness for manual and interrupted cuts, and TiAlN or AlTiN supports high-heat ferrous machining.
Which Machines Use Keyseat Cutters?
CNC Machining Centers
Use automated radial milling passes to cut keyseats on turned or milled shafts.
CNC Lathes with Live Tooling
Mill axial keyways directly on turned shafting in a single setup.
Manual Knee Mills
Used in maintenance and repair work for manual Woodruff keyway cutting.
Applications and Industries for Keyseat Cutters
Woodruff Keyseat Milling
Cuts half-moon keyways in drive shafts for standard Woodruff keys.
Retaining-Ring Grooving
Machines internal and external snap-ring grooves in shafts and bore cavities.
Straight Keyway Slotting
Mills narrow parallel keyseats in power-transmission shafts and gear hubs.
T-Slot and Undercut Milling
Cuts narrow side channels and clearance undercuts in machinery components.
Frequently Asked Questions About Keyseat Cutters
What is the difference between straight-tooth and staggered-tooth keyseat cutters?
Straight teeth align parallel to the cutter axis and suit lighter keyways and non-ferrous materials. Staggered teeth use alternating axial rake angles to shear metal progressively, break chips, reduce chatter, and improve finish in tougher alloys.
How do I select the right size keyseat cutter for a Woodruff key?
ANSI Woodruff cutter numbers encode nominal width and diameter. In the source example, a #404 cutter is 4/32" (1/8") wide and 4/8" (1/2") in diameter. Confirm the required cutter against the key and drawing.
Can a keyseat cutter plunge axially into material?
No. Standard keyseat cutters are non-center-cutting and are intended for radial in-feed and side milling. Position the tool at an open edge or a prepared clearance area before feeding radially.
How do I limit chatter when milling deep keyways?
Use a rigid cutter and workholding setup, keep tool projection short, consider staggered-tooth geometry, and provide effective coolant or cutting oil for chip evacuation.
Does Bauron manufacture custom keyseat cutters?
Bauron can review non-standard head diameters, custom face widths, neck-clearance lengths, and application-specific coatings based on part drawings.
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Design and Engineering Support
Bauron provides design and engineering support for custom geometries, specialized coatings, and application-specific keyseat milling requirements.
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