MTD Genuine Parts 42" 3-in-1 Blade Set

What It Is

This is a set of three 42-inch MTD Genuine OEM blades designed for mulching, bagging, and side-discharge on compatible riding mowers. It’s a direct replacement part for tractors that use MTD’s 3-in-1 cutting system, meaning you can switch between collection, mulching, and discharge without swapping blades.

Fitment & Compatibility

Before buying, confirm your mower has a 42-inch cutting deck and accepts a 3-blade setup. This set is OEM from MTD, so it fits most MTD-branded tractors (including Cub Cadet, Troy-Bilt, Yard Machines, and Craftsman models built by MTD) with a 42-inch stamped deck. Check your mower’s model number and verify the blade part number cross-references to MTD 742-0420, 942-0420, or 742-0420A. Measure your current blades: each blade should be roughly 15.5 inches long with a 5-point star center hole and a 0.25-inch thickness. If your deck uses a different blade pattern or length, this set won’t fit.

Key Things to Buy

• Quality: These are genuine MTD parts, so you get consistent heat treatment and balance out of the box—no warping or dull edges like some aftermarket sets.
• Installation Difficulty: Moderate. You’ll need a socket wrench and a torque wrench (aim for 70-90 ft-lbs). The blades come pre-sharpened, but you must ensure they’re oriented correctly (cutting edge facing the direction of rotation).
• Common Gotchas: The 3-blade design means you need to check for deck spindle alignment. If your spindles are worn, the blades may wobble even if the set is balanced. Also, these blades are not compatible with 42-inch fabricated decks or zero-turn mowers—only stamped decks on lawn tractors.
• Maintenance: Replace when the cutting edge is rounded or nicked, typically every 1-2 seasons depending on use. Sharpen only if you have a blade balancer; unsharpened use reduces lift.

Should You Buy It

Buy this if you own an MTD-family 42-inch lawn tractor and want a reliable, hassle-free OEM replacement that covers all three cutting modes. It’s a solid value for the price, especially if you prefer not to risk fitment issues with aftermarket blades. Skip it if you have a different deck size, a non-MTD brand, or need blades for a fabricated deck.