Rotary 11506 PK3 Blades

What It Is

The Rotary 11506 PK3 is a set of three 20-inch mower blades designed for residential zero-turn and riding mowers. They are a direct replacement for OEM blades on select models, intended for standard mulching or bagging applications.

Fitment & Compatibility

Before buying, confirm your mower deck size is 20 inches (blade length). These blades fit many John Deere, Husqvarna, Craftsman, and MTD models using a 5-point star center hole and a 1-inch diameter spindle. Check your owner’s manual for OEM part numbers like John Deere AM137413 or Husqvarna 532137413. Measure your current blade length from tip to tip and verify the center hole shape—these won’t fit round-hole spindles. Aftermarket, so verify deck pattern (e.g., 3-blade 60-inch decks). Avoid if your deck uses a different hole pattern or offset.

Key Things to Know

• Quality: Medium-carbon steel, pre-sharpened, and balanced. Good for average residential use, but not as durable as premium heat-treated blades for heavy-duty or rocky terrain.
• Installation: Easy with a socket wrench. Use a blade removal tool to lock the spindle. Torque bolts to 70-80 ft-lbs. Always disconnect the spark plug first.
• Gotchas: The 5-point star hole is standard, but some older or non-standard decks use a diamond or keyhole shape. Check for blade offset (these are flat, not angled) to avoid poor lift.
• Lift: Designed for moderate airflow; not ideal for wet grass or deep mulching. Expect some clumping if cutting tall, damp grass.

Should You Buy It

Buy if you have a 20-inch deck with a 5-point star spindle and need affordable, reliable blades for regular mowing on average lawns. Skip if you have a round-hole spindle, need heavy-duty blades for rough terrain, or require high-lift for mulching thick grass.