Key Stock

Key Stock

When a gear, pulley or sprocket starts slipping on its shaft, the cause is often a missing or worn key. Key stock is a common repair part used in farm equipment, small engines and general mechanical work. Tractor Supply offers a range of key stock sizes and profiles as part of our rugged hardware selection, built for jobs that need a reliable fix.

Metal Keys Built for Shaft and Hub Assemblies

A key stock is a small metal piece that fits into a matching slot to lock a rotating component to a shaft so both turn as one unit. A hub that loses its key can spin freely on the shaft instead of driving it, and that puts stress on nearby parts in a hurry. Whether used in gears, pulleys, couplings or sprockets, key stock plays a critical role in maintaining alignment and preventing mechanical failure.

Fasteners of this type show up across a wide range of equipment, from lawn mower blade hubs and tractor drives to electric motors and small engine assemblies. We offer key stocks in a variety of materials, sizes and profiles, including square, rectangular and semi-circular (woodruff), to match the demands of your application.

Square Keys for General-Purpose Shaft Work

Square keys have a flat, rectangular shape that fits the slot cut into most shafts and hubs. That slot is called a keyway, and when the key seats into matching keyways on both pieces, it locks them together so rotation transfers directly from one to the other. Sizing is consistent across manufacturers, so a 1/4-in. key fits any 1/4-in. keyway, regardless of the brand of equipment you're working on. Widths range from 1/8 in. to 1/2 in., covering the shaft sizes found in most residential and light farm machines. A few common sizes in your toolbox means most shaft repairs get done without a parts run.

Woodruff Keys for Curved Keyway Slots

Some shafts taper toward the end instead of maintaining a constant diameter, and that shape requires a key that matches it. The Woodruff key is in the shape of a half-circle, and it fits into a rounded slot cut into the shaft rather than a flat-bottomed groove. That curved seat keeps the key from sliding sideways when the load shifts during operation. Small engines commonly use this style to hold components such as flywheels and crankshafts in place, where a square key would rock or seat unevenly against the shaft surface.

Explore Key Stock from Tractor Supply

A worn or missing key can take down a piece of equipment that would otherwise have years of work left in it. Running your equipment without a proper key accelerates keyway wear, turning a simple key replacement into a far more complex and costly repair, which is the last thing you want. Find key stock in various profiles and sizes to keep your equipment running smoothly, along with the rest of our tools inventory, on our website or at your local Tractor Supply store.