What is Keystock?
Keystock is square or rectangular bar stock used to make machine keys. Once cut to size, a key sits in matching keyways in the shaft and hub to create a positive, slip-free drive for pulleys, sprockets, couplings, and similar components.
What size keystock do I need for my shaft?
- Match the nominal key width and height to the shaft and hub keyway dimensions.
- Test-fit the bar: it should slide fully into both keyways and seat without rocking.
- For worn or slightly inconsistent keyways, consider undersize or oversize fit options (see below).
Oversize vs undersize keystock, what’s the difference?
- Standard fit: sized near nominal for typical new keyways.
- Oversize fit: slightly larger to take up clearance for a tighter side fit.
- Undersize fit: slightly smaller to ease assembly or suit keyways that vary a bit.
Materials & finishes
- Carbon steel: strong, easy to machine; often plain or zinc plated.
- Stainless steel: corrosion resistance for damp or washdown areas.
- Brass/Bronze: non-sparking, good for corrosion resistance and fitting work.
Common lengths & profiles
- Square and rectangular profiles in popular inch sizes.
- Typical stock lengths include 1 ft, 3 ft, 6 ft, and 12 ft (cut to your final length).
How to select keystock (quick guide)
- Measure the keyway width in the shaft and hub; choose the nominal size that fits both.
- Pick a fit class (standard/oversize/undersize) based on desired seating and assembly effort.
- Confirm the key seats fully without lifting the hub; deburr and lightly chamfer key ends.
- Select material/finish for the environment and strength needed.
- Cut length for full engagement across the hub; avoid overhang that could interfere with components.
Typical applications & industries
- Motors and gearboxes driving pulleys, sprockets, or couplings
- Conveyors, mixers, pumps, and general machinery
- Maintenance/MRO repairs and retrofit kits
Installation & best practices
- Verify fit in both keyway and keyseat; the key should seat without rocking.
- Deburr/chamfer edges; keep mating surfaces clean and lightly oiled as appropriate.
- Align components before tightening; recheck after initial run-in.
- Inspect keys during maintenance for wear, peening, or fretting and replace as needed.
Troubleshooting & tips
- Key rocks in the keyway: size/fit mismatch. Try oversize stock or rework to a proper sliding fit.
- Hub won’t seat fully: burrs or raised edges. Deburr and check key height against the hub keyway depth.
- Corrosion in service: step up to stainless or use plated carbon steel for added protection.
Related power-transmission hardware
- Shaft collars and set screws
- Couplings, pulleys, and sprockets
- Keyway broaches, bushings, and shims
- Retaining rings and bearings
Why buy Keystock from AlbanyCountyFasteners.com
- Square and rectangular profiles in popular inch sizes
- Material choices including carbon steel, zinc-plated steel, stainless, and non-ferrous
- Practical lengths for quick cutting and field service
- USA-based support for sizing, fit, and installation questions
FAQs
Helpful answers on sizing, fits, materials, and setup for keystock.
How do I choose the correct keystock size?
Match the nominal width and height to the shaft and hub keyways, then test for a snug sliding fit without rocking.
When should I use oversize or undersize keystock?
Use oversize for tighter side fit or to take up clearance; use undersize for easier assembly or slightly inconsistent keyways.
What material should I pick?
Use carbon steel for general service, stainless for corrosion resistance, and brass/bronze for non-sparking or fine fitting.
Can I cut and machine keystock?
Yes. Cut to length, deburr, and lightly chamfer edges. Ensure full hub engagement with no overhang.
Does keystock need lubrication?
Keep seating surfaces clean and lightly oiled during assembly; avoid heavy lubrication that could attract debris in dusty environments.