Gravely ZT HD (44/48/52/60, Residential Zero-Turn) Blade Bolt Torque
The blade bolt torque on the Gravely ZT HD (44/48/52/60, Residential Zero-Turn) is 115–160 lb-ft (156–217 N·m). Gravely ZT HD Operator's Manual 30204000D (models 991267 ZT HD 44, 991269 ZT HD 48, 991277 ZT HD 52, 991279 ZT HD 60), p.25, Install Blades: "Reinstall blades and secure with original hardware. Torque to 156 – 217 N•m (115 – 160 lb-ft)." Also confirmed in the CRITICAL TORQUES table on p.46: "Blade to spindle 1380 – 1920 [lb-in] 115 – 160 [lb-ft] 156 – 217 [N·m]." Socket and thread size are not stated.
What's the exact spec for the Gravely ZT HD (44/48/52/60, Residential Zero-Turn)?
Torque: 115–160 lb-ft (156–217 N·m). Threadlocker: Not called for in the Gravely manuals cited below. Gravely ZT HD Operator's Manual 30204000D (models 991267 ZT HD 44, 991269 ZT HD 48, 991277 ZT HD 52, 991279 ZT HD 60), p.25, Install Blades: "Reinstall blades and secure with original hardware. Torque to 156 – 217 N•m (115 – 160 lb-ft)." Also confirmed in the CRITICAL TORQUES table on p.46: "Blade to spindle 1380 – 1920 [lb-in] 115 – 160 [lb-ft] 156 – 217 [N·m]." Socket and thread size are not stated.
Step-by-step Gravely ZT HD (44/48/52/60, Residential Zero-Turn) blade-bolt reinstall
1) Disconnect the spark plug and engage the parking brake. 2) Block the blade with a 2×4 wedged against the deck shell — never your hand. 3) Use a 1/2" drive breaker bar with an impact socket sized to the blade bolt to break the bolt loose. 4) Clean threads with brake cleaner and inspect the bolt for stretch. 5) Reinstall with no threadlocker. 6) Torque to 115–160 lb-ft (156–217 N·m) in one smooth pull with a calibrated torque wrench. 7) Re-check after the first hour of cutting.
Common Gravely ZT HD (44/48/52/60, Residential Zero-Turn) blade-bolt mistakes
Over-torque past spec stretches the bolt past yield — it will not hold the next reinstall. Under-torque lets the blade walk loose at full RPM, which destroys the spindle key and balance. Using a 12-point socket on a rusted bolt rounds the head; always use 6-point. The Pro-Turn manual cautions that mating surfaces between spindle, lower spindle guard, blade and washer "MUST be free of debris to ensure correct tightness and alignment" — clean them before torquing, or the 115–160 lb-ft reading is meaningless.
What socket fits the Gravely ZT HD (44/48/52/60, Residential Zero-Turn) blade bolt?
A 6-point impact socket sized to the blade bolt — the manual doesn’t state an exact size, so confirm it against the bolt head before buying one on a 1/2" drive breaker bar. A 12-point socket can be used in a pinch on a clean, sharp-edged bolt head — never on a rusted bolt.
Related lookups
- All Gravely Blade Bolt Torque Specs
- All Mower Brand Blade Specs
- Wrench & Socket Size Finder
- Gravely ZT-XL 52 (Residential Zero-Turn) (80–120 lbf-ft (108–163 N·m))
- Gravely Pro-Turn 260 (Commercial Zero-Turn) (115–160 lb-ft (156–217 N·m))
- Gravely Pro-Turn 100 (148/152/160, Commercial Zero-Turn) (115–160 lb-ft (155.9–216.9 N·m))
- Gravely Pro-Turn 300 (352/360/372, Commercial Zero-Turn) (115–160 lb-ft (156–217 N·m))
- Gravely Pro-Turn 500 (552/560/572, Commercial Zero-Turn) (115–160 lb-ft (156–217 N·m))
- Gravely Pro-Turn 600 (652/660/672, Commercial Zero-Turn) (115–160 lb-ft (156–217 N·m))
- Gravely Pro-Turn Mach One (992515/992519, Commercial Zero-Turn) (115–160 lb-ft (156–217 N·m))
- Gravely Pro-Turn ZX (48/52/60, Commercial Zero-Turn) (115–160 lb-ft (156–217 N·m))
- Gravely Compact-Pro 34 (Commercial Compact Zero-Turn) (115–160 lb-ft (156–217 N·m))
- Gravely Pro-Stance (32/36/48/52/60, Commercial Stand-On) (115–160 lb-ft (156–217 N·m))
- Gravely Pro-Stance Ultra (52/60/72, Commercial Stand-On) (115–160 lb-ft (156–217 N·m))
- Gravely Z-Stance (32/48/52, Commercial Stand-On) (115–160 lb-ft (156–217 N·m))
- Gravely Pro-Walk Hydro (36/48/52/60, Commercial Walk-Behind) (115–160 lb-ft (156–217 N·m))
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