331737B 406712 Mulching Blade with Circle Mounting Pattern, 21" Lawn Mower Blade Compatible with Craftsman, Husqvarna 21 inch Deck Push Walk Behind Lawnmower, Replace for 165833, 175064, 189028 (2Pcs)

What It Is

This is a 21-inch mulching blade set (2-pack) with a circle mounting pattern, designed for push and walk-behind lawn mowers from Craftsman, Husqvarna, and other brands with 21-inch decks. It replaces OEM part numbers 165833, 175064, and 189028, and is intended for mulching grass clippings into fine particles that decompose quickly.

Fitment & Compatibility

Before buying, confirm three things:

1. Deck size: Only for 21-inch decks. Measure your blade from tip to tip (not the deck housing).
2. Mounting pattern: Circle pattern with a 3-inch center hole and 5-point star drive. If your mower uses an oval or diamond hole, this won’t fit.
3. Brand/model: Direct fit for most Craftsman and Husqvarna 21-inch push mowers (e.g., 900 series, 700 series). Also fits some Poulan, McCulloch, and MTD models with the same pattern. Check your owner’s manual for OEM numbers 165833, 175064, or 189028.

Always measure your old blade’s length, center hole diameter, and thickness (this blade is 0.125 inch thick). Verify the blade adapter/drive washer shape matches.

Key Things to Know

• Quality: Made from hardened steel with a painted finish. Reviews note they stay sharp for 5–10 mowings on typical lawns.
• Installation: Easy if you have a socket wrench and blade removal tool. Torque to 30–40 ft-lb. Use thread locker if your mower vibrates heavily.
• Gotcha: These are mulching blades only—not for bagging or side discharge. They have a high-lift design that creates more suction, which can strain smaller engines if grass is wet or thick.
• Balance: Out of the box, they’re balanced. But if you sharpen them, re-check balance to avoid vibration.

Should You Buy It

Buy this set if you have a 21-inch Craftsman or Husqvarna push mower with a circle mounting pattern and want affordable, decent-quality mulching blades for regular lawn maintenance. Skip it if you need a bagging or high-lift blade, or if your mower uses an oval or diamond mounting hole.