Engine Woodruff keys that aren’t the exact size can wreck a crankshaft taper and cost hundreds to repair. This list shows 10 kits that combine toughness, tight tolerances, and clear labeling for engine work. Included are metric assortments, crankshaft-specific keys for ATVs, and large 160–210 piece sets for varied projects.
Read on to pick the right hardness and finish to match your engine’s needs.
| 110-Piece Metric Woodruff Key Assortment Kit |
| Most Complete Set | Material: High-hard carbon steel | Shape / Type: Woodruff (semi-circle / half-moon) | Use / Application: Automotive and machinery; crankshafts, shafts, pulleys | VIEW LATEST PRICE | Read Our Analysis |
| Woodruff Key Assortment Metric Carbon Steel (80pc) |
| Cost-Effective Choice | Material: High-grade carbon steel | Shape / Type: Woodruff (half-moon) | Use / Application: Automotive and machinery; pulleys and drive shafts | VIEW LATEST PRICE | Read Our Analysis |
| 200pcs Metric Woodruff Key Assortment Kit |
| Heavy-Duty Assortment | Material: High hard carbon steel | Shape / Type: Woodruff (semi-circle / half-moon) | Use / Application: Automotive engines, industrial machinery, machine tools | VIEW LATEST PRICE | Read Our Analysis |
| Crankshaft Woodruff Keys for Yamaha ATVs and UTVs |
| OEM Fitment Pick | Material: (OEM replacement) Steel (crankshaft woodruff key) | Shape / Type: Woodruff (crankshaft woodruff key) | Use / Application: Yamaha crankshaft replacement (ATV/UTV/motorcycles) | VIEW LATEST PRICE | Read Our Analysis |
| Woodruff Key Assortment 120pcs (Half Moon) |
| Organized Essentials | Material: High-quality carbon steel | Shape / Type: Woodruff (half-moon) | Use / Application: Automotive engines, industrial machinery, machine tools | VIEW LATEST PRICE | Read Our Analysis |
| Performance Tool W5343 80Pc Woodruff Key Assortment SAE Grey |
| SAE Maintenance Kit | Material: Metal (steel) construction | Shape / Type: Woodruff (SAE half-moon) | Use / Application: Securing gears, pulleys, sprockets to shafts (maintenance/repair) | VIEW LATEST PRICE | Read Our Analysis |
| Yinpecly Woodruff Key Assortment Kit (120pcs) |
| Reliable Standard Set | Material: High hard carbon steel | Shape / Type: Woodruff (semi-circle / half-moon) | Use / Application: Automotive engines, industrial machinery, machine tools | VIEW LATEST PRICE | Read Our Analysis |
| 210pcs Round Ended Parallel Drive Shaft Key Set |
| Parallel Key Specialist | Material: 45# carbon steel | Shape / Type: Parallel drive / round-ended (shaft key) — similar keyed stock style | Use / Application: Connecting gears/pulleys/flywheels to shafts (automotive, industrial) | VIEW LATEST PRICE | Read Our Analysis |
| Woodruff Key Assortment Kit (175 pcs 8–30mm) |
| Wide Size Range | Material: High hard carbon steel | Shape / Type: Woodruff (half-moon / round-ended) | Use / Application: Automotive, machinery, keyed connections on shafts | VIEW LATEST PRICE | Read Our Analysis |
| Woodruff Key Assortment Kit (8mm–30mm 160 pcs) |
| Workshop Staple | Material: Premium keyway material (steel) | Shape / Type: Woodruff (round-ended / feather key style for keyways) | Use / Application: Small engines, go-karts, motors, industrial/repair applications | VIEW LATEST PRICE | Read Our Analysis |
More Details on Our Top Picks
110-Piece Metric Woodruff Key Assortment Kit
Should you work on cars or machines and want a reliable starter kit, the 110-piece Metric Woodruff Key Assortment Kit is a smart pick that keeps you ready for many repairs. You get 15 sizes that span thicknesses from 2.5 mm to 8 mm and lengths from 10 mm to 32 mm, with heights of 4 mm to 13 mm, so you can match most crankshaft and shaft keyways. Made from high-hard carbon steel, these keys resist wear, shake, and corrosion, and have low friction. The clear labeled storage box keeps parts organized, and assistance is available in case you require help.
- Material:High-hard carbon steel
- Shape / Type:Woodruff (semi-circle / half-moon)
- Use / Application:Automotive and machinery; crankshafts, shafts, pulleys
- Packaging / Storage:Classified storage box with clear model labels
- Size Range / Assortment Count:110 pcs; 15 metric sizes (thickness 2.5–8 mm; length 10–32 mm; height 4–13 mm)
- Precision / Fit:Fine workmanship; precision fit for keyways
- Additional Feature:Classified storage box
- Additional Feature:15-size variety
- Additional Feature:Low friction finish
Woodruff Key Assortment Metric Carbon Steel (80pc)
Should you work on cars or machines and want a reliable set that covers most common needs, the Woodruff Key Assortment Metric Carbon Steel 80pc is a smart choice you’ll appreciate. You get 80 pieces in eight sizes that fit many shafts and pulleys, so you won’t hunt for the right key. The keys use high grade carbon steel, so they resist wear and corrosion and last through tough jobs. Precision manufacturing gives accurate fit and secure connections, which keeps parts aligned. A sturdy plastic case with clear labels keeps keys organized and easy to grab whenever you need them.
- Material:High-grade carbon steel
- Shape / Type:Woodruff (half-moon)
- Use / Application:Automotive and machinery; pulleys and drive shafts
- Packaging / Storage:Sturdy plastic case with clear label, organized compartments
- Size Range / Assortment Count:80 pcs; 8 sizes (listed mm per piece)
- Precision / Fit:Precision-engineered; accurate fit into intended slots
- Additional Feature:Cost-effective supply
- Additional Feature:Sturdy plastic case
- Additional Feature:Precision-engineered fit
200pcs Metric Woodruff Key Assortment Kit
Should you work on engines, farm equipment, or machine tools and want one reliable kit that covers most repair jobs, this 200pcs metric Woodruff key assortment is a great choice for you. You get 200 pieces in 15 popular metric sizes, all semi-circle woodruff shapes that fit keyways snugly. Made from high hard carbon steel, they resist wear and hold torque between shafts and components. You can use them on cars, tractors, and machine tools. The durable plastic case keeps sizes organized and easy to reach. You’ll feel confident repairing parts with this practical, well-made assortment.
- Material:High hard carbon steel
- Shape / Type:Woodruff (semi-circle / half-moon)
- Use / Application:Automotive engines, industrial machinery, machine tools
- Packaging / Storage:Durable plastic storage case
- Size Range / Assortment Count:200 pcs; 15 metric sizes
- Precision / Fit:Precision-engineered to fit keyways snugly
- Additional Feature:Largest quantity option
- Additional Feature:Durable plastic case
- Additional Feature:Popular-size coverage
Crankshaft Woodruff Keys for Yamaha ATVs and UTVs
In case you ride Yamaha ATVs or UTVs and need a reliable replacement part, these crankshaft Woodruff keys are a smart choice because they fit a wide range of models and years, so you won’t waste time guessing compatibility. You’ll get two MOTO1988 crankshaft keys with OEM numbers 90280-16053-00, 90280-05048-00, 90280-05001-00. They work on many bikes like DT, YZ, XT families and on ATVs such as Big Bear, Grizzly, Raptor, Kodiak, Wolverine, Bruin, Timberwolf and UTVs like Rhino and Viking plus select snowmobiles. Check year, model, submodel and part numbers to confirm fit.
- Material:(OEM replacement) Steel (crankshaft woodruff key)
- Shape / Type:Woodruff (crankshaft woodruff key)
- Use / Application:Yamaha crankshaft replacement (ATV/UTV/motorcycles)
- Packaging / Storage:Loose 2-piece pack (replacement keys; no multi-compartment case)
- Size Range / Assortment Count:2 pcs; single OEM sizes for specific Yamaha models
- Precision / Fit:OEM-fit crankshaft key for exact model compatibility
- Additional Feature:OEM part numbers listed
- Additional Feature:Vehicle-specific fitment
- Additional Feature:Sold in 2-piece sets
Woodruff Key Assortment 120pcs (Half Moon)
Should you work on cars, farm gear, or workshop machines and want a simple, reliable way to lock rotating parts to shafts, this 120-piece Woodruff key assortment is a great choice for you. You get ten sizes in a clear, sturdy box so parts stay sorted and handy. Made from high-quality carbon steel, these half-moon keys fit keyways precisely, holding gears, pulleys, and flywheels firmly to shafts for accurate torque transfer. You’ll appreciate durable, damage-resistant pieces that won’t fail mid-repair. The sizes cover common needs, so you can fix engines, machine tools, and agricultural gear without hunting for the right key.
- Material:High-quality carbon steel
- Shape / Type:Woodruff (half-moon)
- Use / Application:Automotive engines, industrial machinery, machine tools
- Packaging / Storage:Transparent, sturdy storage box with fixed compartments
- Size Range / Assortment Count:120 pcs; 10 sizes (detailed counts per size)
- Precision / Fit:Precisely matches keyways; reliable fixation
- Additional Feature:Transparent compartmented box
- Additional Feature:Ten-size selection
- Additional Feature:Mixed quantity distribution
Performance Tool W5343 80Pc Woodruff Key Assortment SAE Grey
Should you do regular engine work or maintain older American vehicles, the Performance Tool W5343 80Pc Woodruff Key Assortment is a smart pick because it gives you the common SAE sizes you’ll reach for most often and keeps them neatly stored for quick repairs. You’ll find 80 metal pieces in eight popular sizes, including 1/8 x 3/16 x 33/64 and 1/8 x 1/4 x 41/64, all made to fit imperial shafts, gears, pulleys and sprockets. The grey set comes in a re-sealable plastic case that organizes parts and keeps them accessible. It’s durable, handy and made in China.
- Material:Metal (steel) construction
- Shape / Type:Woodruff (SAE half-moon)
- Use / Application:Securing gears, pulleys, sprockets to shafts (maintenance/repair)
- Packaging / Storage:Re-sealable plastic case
- Size Range / Assortment Count:80 pcs; 8 SAE sizes
- Precision / Fit:Machined sizes for routine maintenance fit (SAE)
- Additional Feature:SAE (imperial) sizes
- Additional Feature:Re-sealable case
- Additional Feature:China origin
Yinpecly Woodruff Key Assortment Kit (120pcs)
Should you work on engines or machines and want a reliable set that’s ready whenever you are, the Yinpecly Woodruff Key Assortment Kit (120pcs) fits the bill perfectly. You get 120 pieces in ten metric sizes, all semi circle woodruff keys made from high hard carbon steel. They’re precision cut to fit keyways and lock gears, spindles, and shafts so parts don’t slip. A durable plastic case keeps everything tidy and easy to grab. Whether you’re a mechanic, hobbyist, or woodworker, this kit gives strength, accuracy, and organization, so you’ll feel confident tackling automotive and industrial projects.
- Material:High hard carbon steel
- Shape / Type:Woodruff (semi-circle / half-moon)
- Use / Application:Automotive engines, industrial machinery, machine tools
- Packaging / Storage:Durable plastic storage case
- Size Range / Assortment Count:120 pcs; 10 sizes
- Precision / Fit:Precision-engineered for accurate fit in keyways
- Additional Feature:High-hard carbon steel
- Additional Feature:Durable carry case
- Additional Feature:Suitable for woodworkers
210pcs Round Ended Parallel Drive Shaft Key Set
Should you work on engines, machines, or DIY projects and want a reliable set that saves time and frustration, this 210 piece Round Ended Parallel Drive Shaft Key Set is a smart choice for you. You’ll find fifteen metric sizes in a clear, sturdy case that keeps each size tidy and ready. Made from 45# carbon steel, these keys resist breakage and hold parts firmly to shafts. Use them for gears, pulleys, and flywheels in cars, tools, or farm gear. With plenty of pieces for many jobs, you’ll feel prepared, confident, and less stressed whenever repairs call.
- Material:45# carbon steel
- Shape / Type:Parallel drive / round-ended (shaft key) — similar keyed stock style
- Use / Application:Connecting gears/pulleys/flywheels to shafts (automotive, industrial)
- Packaging / Storage:Transparent sturdy case with fixed compartments
- Size Range / Assortment Count:210 pcs; 15 metric sizes (detailed counts per size)
- Precision / Fit:Precisely sized for secure fit to rotating shafts
- Additional Feature:45# carbon steel
- Additional Feature:Detailed piece counts
- Additional Feature:Long-length keys included
Woodruff Key Assortment Kit (175 pcs 8–30mm)
Should you work on engines, machines, or home projects and want a single kit that covers almost every common Woodruff key need, this 175-piece assortment is a smart choice. You get 15 sizes from 8 mm to 30 mm, so you rarely hunt for the right half-moon key. The keys are round-ended and made from high hard carbon steel, which gives strength, wear resistance, and corrosion protection. They fit accurately in key slots and hold shafts and cranks securely. A durable plastic case keeps pieces organized and ready. You’ll enjoy broad coverage, reliable performance, and clear value for workshops.
- Material:High hard carbon steel
- Shape / Type:Woodruff (half-moon / round-ended)
- Use / Application:Automotive, machinery, keyed connections on shafts
- Packaging / Storage:Durable plastic storage case
- Size Range / Assortment Count:175 pcs; 15 sizes (8–30 mm)
- Precision / Fit:Precision-engineered for accurate fit in slots
- Additional Feature:Broad 8–30mm coverage
- Additional Feature:Corrosion-resistant finish
- Additional Feature:Mid-large kit size
Woodruff Key Assortment Kit (8mm–30mm 160 pcs)
In case you work on small engines, go-karts, or workshop repairs and want one reliable kit to cover most jobs, this Woodruff key assortment is a smart pick because it gives you 160 precision-machined keys in sizes from 8mm to 30mm. You’ll appreciate the 15 sizes that match common shafts and keyways, and the premium material lets you trust them under stress. The keys fit consistently, so you won’t fight alignment. A compartmented plastic case keeps parts sorted and fast to find, which speeds repairs. Use this kit for motors, tractors, motorcycles, and industrial assembly with quiet confidence.
- Material:Premium keyway material (steel)
- Shape / Type:Woodruff (round-ended / feather key style for keyways)
- Use / Application:Small engines, go-karts, motors, industrial/repair applications
- Packaging / Storage:Compartmentalized plastic case
- Size Range / Assortment Count:160 pcs; 15 sizes (8–30 mm)
- Precision / Fit:Precision-machined dimensions for dependable fit
- Additional Feature:Suitable for small engines
- Additional Feature:Industrial-grade use
- Additional Feature:Compartmentalized case
Factors to Consider When Choosing Engine Woodruff Keys
As you pick an engine Woodruff key, start alongside matching material hardness and size so the key fits snugly and resists deformation. You’ll also want corrosion and wear resistance to keep the key reliable over time, while precision and tight tolerances guarantee smooth power transfer. Considering these factors together helps you choose a key that lasts and keeps your engine running confidently.
Material Hardness Rating
You’ll often find that the hardness of an engine woodruff key is one of the initial things you should check before choosing or replacing one, because it controls how the key wears, bends, and fails under load. You want a balance. Carbon steels in HRC 30–50 give you shear strength and some ductility, so they resist wear without snapping. In the event hardness falls below HRC 30, the key can deform and cause fretting in high torque engines. Provided it’s above HRC 50, brittleness raises the risk of fracture on impact. Case hardened keys add a hard surface HRC 55–62 over a tougher HRC 30–40 core, combining wear resistance with shock tolerance. Always match original hardness and confirm with Rockwell or Vickers testing.
Size And Fit
After you’ve checked hardness, the next thing to focus on is how the key actually fits the shaft and hub; size and fit decide whether the engine will run smooth or start making trouble. You’ll measure the keyseat width and the shaft radius initially. Standard thicknesses run from about 2.5 mm to 8 mm and lengths from roughly 10 mm to 32 mm, so pick a key that matches the machined slot. Make sure the semicircular profile matches shaft curvature so it seats flush without gaps or sticking out. Check arc length so it engages the hub without slipping or bottoming out. Consider fit class too. Use clearance fits for light duty and snug or interference fits for high torque. Finally, match thickness to expected loads.
Corrosion Resistance Properties
Because engine parts often live in wet, salty, or humid places, you should pick a Woodruff key that won’t let corrosion steal strength or ruin the fit. You want material and finish that match the job and last. Should you choose high carbon or alloy steel for strength, plan on zinc, black oxide, phosphate, nickel, or cadmium coatings to protect the surface. Each coating gives different salt spray resistance, so pick one rated for your environment. Stainless options like 304 or better 316 remove the need for plating and resist chloride attack, which helps in marine or road salt conditions. Also check mating metals to avoid galvanic problems. Use similar metals or add thin insulating coatings whenever dissimilar pairs are unavoidable.
Wear Resistance Performance
You picked a corrosion-resistant key, and now you want it to last under motion and load, so wear resistance becomes the next thing to check. Pick keys made from high-hard carbon steel or heat-treated alloys because hardness above about HRC 40 helps resist wear during repeated cycles. At the same time, choose treatments like case hardening or carburizing to protect the surface from pitting and abrasive damage. Balance hardness with toughness so the key won’t snap under shock loads. Also focus on lubrication, alignment, and load levels, since poor lubrication or misalignment speeds wear. Finally, insist on precise machining and smooth surface finish to prevent fretting and micro-movement. These choices work together to give your key long, reliable service.
Precision And Tolerance
As you pick a Woodruff key, tight tolerances and precise fits matter more than you might think, so pay attention to size, clearance, and alignment from the start. You want keys made to specified tolerances for radius, thickness, and height. For small keys tolerances around ±0.05 mm work well, and larger keys could be ±0.1 mm. Also check radial clearance. A fit near 0.01 to 0.05 mm keeps the key from moving without causing interference. Shaft runout and hub concentricity matter too. Should axial misalignment exceed 0.1 mm, the key will carry uneven loads and fatigue faster. Surface finish under Ra 1.6 µm and rounded edges lower stress risers. Finally, confirm hardness and heat treatment so wear and shear strength meet expectations.
Storage And Organization
Tight fits and correct tolerances matter in the machine shop, and they also change how you store Woodruff keys to keep them ready and reliable. You want a compartmentalized plastic case with clear, labeled slots so each size stays separate and is instantly identifiable. Group keys through thickness and diameter, for example 2.5–3.5 mm, 4–5 mm, 6–8 mm, and arrange largest-to-smallest to speed selection during repairs. Keep inventory counts on the case or a simple checklist, such as 10–40 pieces per common size, so you restock before shortages occur. Store keys in a dry, corrosion controlled place and use a light rust inhibitor or desiccant packs in the case. In the event you work on multiple projects, keep a chief consistency chart near the toolbox with thickness × length × height.
Application Compatibility Range
Upon choosing a Woodruff key, start matching the key’s exact metric or imperial size to the shaft keyway and the mating part, because a near fit can still slip under load and ruin a repair. You’ll check thickness and diameter or width and length against shaft and component tolerances to guarantee torque transfers cleanly. Also confirm common size ranges so you don’t run out during a job, since heights often span about 3 mm to 13 mm and lengths about 10 mm to 32 mm. Match the key profile to the keyway on crankshaft and driven part so seating is positive. Consider material hardness relative to engine torque and RPM, and verify OEM flywheel pulley and timing gear keyways for any variance.
Quantity And Value
Pick a quantity that matches how often you work on engines and what stops you least. In case you do occasional DIY fixes, keep a small kit of 3 to 10 common sizes. In the event you service many engines, get a larger assortment of 50 to 200 plus to avoid repeated orders. Kits with lots of keys usually cost less per piece, so you save money over time. Also stock duplicates of the sizes you use most, because a missing key can pause a job. Whenever you value a kit, check labeled storage and a wide size range, since organization saves time and stress. Balance initial cost against long term value, and choose the pack that keeps you working and calm.
