(3 Pack) Spindle Blade Nut Fits for Most Mower RZT 50 - RZT 54 - RZT42 | Spindle Nut Fits MTD Craftsman Troy Bilt Mower ,Replaces 912-0417A、712-0417A

What It Is

This is a 3-pack of replacement spindle blade nuts (1/2-20 thread) designed to secure mower blades to the spindle shaft on zero-turn and lawn tractors. It’s intended for use on Craftsman, MTD, and Troy-Bilt mowers, commonly found on RZT 42, RZT 50, and RZT 54 decks.

Fitment & Compatibility

Before buying, verify your mower uses a 1/2-20 thread spindle nut (measure the spindle shaft threads if unsure). This nut replaces OEM part numbers 912-0417A and 712-0417A. It fits most MTD-branded decks on Craftsman, Troy-Bilt, and Cub Cadet zero-turn models from the 2000s onward. Do not rely on deck size alone—some RZT 50 and 54 decks use different thread pitches. Always cross-check your mower’s model number with the 912-0417A or 712-0417A part number.

Key Things to Know

• Torque is critical: Tighten to 70-90 ft-lbs. Under-torquing can loosen the blade; over-torquing can strip the nut or damage the spindle.
• Use a new nut each blade change: These are one-time-use (nylon lock insert degrades). Reusing can lead to blade detachment.
• Not for all spindles: Some newer MTD decks use a 5/8-18 thread nut—this pack won’t fit those. Measure first.
• Includes 3 nuts: Enough for a single replacement on a 3-blade deck, or spares for a 2-blade mower.

Should You Buy It

Buy this if you own an MTD/Craftsman/Troy-Bilt zero-turn with a 50-54 inch deck and need a quick, affordable OEM-spec replacement for routine blade changes. Avoid if your mower uses a different thread pitch (5/8-18) or if you need only one nut—the 3-pack is still a good value for spares.