Rotary 11719 Blade, Pack of 3, 21" X 1/2"

What It Is

The Rotary 11719 Blade (pack of 3) is a 21-inch universal replacement blade for walk-behind mowers, designed for medium-duty residential cutting. Each blade measures 21” x 1/2” (length x width) with a 1” center hole and a 7-point star drive pattern.

Fitment & Compatibility

Before buying, confirm these four things:

• Deck size: Only for mowers with a 21-inch cutting deck. Measure your current blade’s length from tip to tip.
• Center hole and drive pattern: The 1” center hole with a 7-point star drive fits many MTD, Craftsman, Troy-Bilt, Cub Cadet, and Yard Machines models. Check your spindle’s shape – if it’s a 5-point star or a hex shaft, this blade won’t fit.
• OEM cross-reference: Replaces OEM part numbers 11719, 742-11719, 942-11719, and similar. Look up your mower’s model number on the deck or under the seat to verify.
• Blade thickness: These are 0.1875” thick (standard residential). If your mower uses a thicker blade (0.25”), do not substitute – it can cause imbalance or spindle damage.

Key Things to Know

• Quality: Sharp out of the box, but not hardened steel – expect to sharpen after 10-15 hours of use on typical grass. Not for heavy mulching or thick, wet grass.
• Installation: Easy – just remove the old blade, clean the spindle, and torque to 40-50 ft-lbs. Use a blade removal tool to prevent the spindle from spinning.
• Balance: Each blade in the pack is individually balanced, but always check with a blade balancer after sharpening to avoid vibration.
• Common gotcha: The 7-point star pattern can wear over time. If your spindle has visible wear, replace it before installing new blades to prevent wobble.

Should You Buy It

Yes, if you have a 21-inch MTD-style mower and need a budget-friendly multi-pack for routine residential mowing. The price per blade (~$13) is competitive, and the 4.7-star rating reflects solid value. Skip it if you need a premium, long-lasting blade for commercial use or heavy mulching – look for a thicker, hardened-steel option instead.