Mower Mulching Blade Compatible with Craftsman 42 Inch Fits Husqvarna YTH18542 YTA18542 YTH1542 YTH1842 YT150 YTH180 Poulan Pro with 42" Deck Replaces 134149 138971 532134149 422719 138498 (WS-Y0018)

What It Is

This is a replacement mulching blade set designed for 42-inch cutting decks on select Craftsman, Husqvarna, and Poulan Pro lawn tractors. It chops grass clippings finely and recirculates them into the lawn for natural fertilization, ideal for regular mowing without bagging.

Fitment & Compatibility

• Deck size: Only fits 42-inch decks. Measure your deck width (blade tip to tip) to confirm.
• Model fit: Compatible with Husqvarna YTH18542, YTA18542, YTH1542, YTH1842, YT150, YTH180, and Poulan Pro models with 42-inch decks. Also fits some Craftsman models—check your manual or existing blade part number.
• OEM replacement numbers: Replaces 134149, 138971, 532134149, 422719, 138498. Compare these to your current blade’s part number.
• Measurements: Blade length is 21 inches (center hole to tip), center hole diameter is 1 inch, and thickness is 0.25 inches. Verify these against your old blade.
• Gotcha: Not for zero-turn mowers or decks with odd bolt patterns. Confirm your spindle’s bolt pattern (typically 5-point star or 6-point) before buying.

Key Things to Know

• Quality: 4.4/5 rating from 250 reviews indicates good durability for residential use, but may wear faster on rocky or sandy soil.
• Installation: Easy DIY—remove the old blade, clean the spindle, and torque the bolt to 40-50 ft-lbs. Use a blade removal tool or block of wood to prevent spinning.
• Common gotcha: Mulching blades require sharp edges to work well; they dull faster than standard lift blades. Sharpen or replace every 25-30 hours of use.
• Performance: Works best with dry grass—wet clippings can clump and leave piles. For best results, mow frequently and don’t cut more than 1/3 of grass height.

Should You Buy It

If you own one of the listed Husqvarna, Craftsman, or Poulan Pro tractors with a 42-inch deck and want cleaner mulching without bagging, this is a solid, affordable upgrade. It’s easy to install and performs well for typical suburban lawns. Avoid if you have heavy-duty commercial use, wet/overgrown grass, or a deck size other than 42 inches.