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

What It Is

This is a 21-inch mulching blade with a circle mounting pattern, designed for push and walk-behind lawn mowers. It’s intended for use on Craftsman and Husqvarna models with a 21-inch cutting deck, and it replaces OEM part numbers 165833, 175064, and 189028.

Fitment & Compatibility

Before buying, measure your mower deck to confirm it’s exactly 21 inches. Check that the mounting hole pattern is a circle (not an oval or star) and that the center hole diameter matches your spindle. This blade is compatible with select Craftsman and Husqvarna 21-inch push mowers—verify your model number against the manufacturer’s approved list. It is an aftermarket replacement for the listed OEM parts, so it may not be identical in thickness or balance to the original. Always compare the blade length, width, and hole size to your current blade before installing.

Key Things to Buy

• Quality: Made from heat-treated steel, it holds an edge well but may require balancing before first use—check with a blade balancer.
• Installation: Straightforward if you have a socket wrench and a block of wood to lock the blade. Torque the bolt to manufacturer specs (typically 30-50 ft-lbs).
• Gotchas: The circle mounting pattern is less common than star or oval patterns—ensure your spindle matches exactly. Mulching blades need sharp edges for effective cut; dull blades tear grass and cause clumping.
• Performance: Works best with dry grass; wet or tall grass may clog the deck.

Should You Buy It

Buy this blade if you have a 21-inch Craftsman or Husqvarna push mower with a circle mounting pattern and need a reliable, budget-friendly mulching upgrade. It’s a solid replacement for worn OEM blades, but double-check your spindle type to avoid fitment issues.