MTD 490-100-M115 20" Mulching Blade Star for Columbia Bolens Yard-Machines 020 02MY 02M2 02BT 02B 020W OEM-742-0640

What It Is

This is a 20-inch mulching blade designed to replace the OEM part 742-0640 on MTD-built lawn tractors and walk-behinds, including Columbia, Bolens, and Yard Machines models. It uses a Star center hole pattern to lift grass and cut it into fine clippings for natural lawn feeding.

Fitment & Compatibility

Check your deck size – this blade fits only 20-inch cutting decks. Measure your blade length from tip to tip across the center; if it’s not exactly 20 inches, this won’t work.

Star center hole – the blade has a 5-point star center (not a standard oval or round hole). Confirm your spindle matches a star pattern. Common on MTD/Columbia/Bolens/Yard Machines models with part numbers starting in 020, 02MY, 02M2, 02BT, 02B, or 020W.

OEM cross-reference – fits MTD 742-0640 (and 490-100-M115). Aftermarket blades may use a different brand name but must match these numbers. Do not assume a 20-inch blade fits your brand – check your owner’s manual or pull the old blade.

Quick check – remove one blade bolt, lift the old blade, and compare the hole shape and length. If it matches the star pattern and is 20 inches, you’re good.

Key Things to Know

• Mulching vs. bagging – this blade is for mulching only. It has a curved, serrated edge to chop clippings fine. If you need to bag or discharge, buy a separate blade set.
• Installation – easy if you have a socket wrench and torque wrench. Tighten the center bolt to 35-50 ft-lbs. Use thread locker if your manual recommends it.
• Balance check – after installing, spin the blade by hand. If it wobbles or vibrates, the blade may be unbalanced. A $10 blade balancer is worth it.
• Common gotcha – the star hole can wear out over time if the bolt is loose. Always check the spindle for damage before installing a new blade.

Should You Buy It

If you own a 20-inch MTD-family mower (Columbia, Bolens, Yard Machines) with a star spindle and want to mulch leaves and grass into fine clippings, this blade is a solid, OEM-quality choice. At $26.49, it’s well-priced for a direct replacement that avoids aftermarket fitment headaches. Skip it if you need a bagging or standard lift blade.