CompareUpdated September 14, 2026
FM-78H vs NAM72H: 30 vs 45 HP floors
Two hydraulic H decks that look interchangeable until you read the floors. FM-78H is a 70″ Woodmaxx (the “78” is not the cut) from 30 PTO HP. NAM72H is a true 72″ NAM-H from 45 PTO HP with 16″ of slider travel, not PTO-edge reach.
By Tom Brennan · Editor
$4,620 · 70″ · 30–65 PTO HP
$2,999 · 72″ · 45–85 PTO HP
Buyer fit
Who should buy FM-78H vs NAM72H
Width is a 2″ gap. Horsepower and geometry are not. Treat the 45 HP NAM72H floor as a hard filter, then decode offset before you spend the Woodmaxx premium.
Buy the FM-78H if…
- + Your tractor lives in the 30–45 PTO HP band, where NAM72H is below floor.
- + You want Y-blades at order, a slip clutch, and a 2-year parts warranty.
- + Fence and orchard work needs published cut-edge-from-PTO numbers, not a 16″ slider nudge.
Buy the NAM72H if…
- + You honestly have 45–85 PTO HP and lift for a 745 lb Cat 1 deck.
- + 72″ plus ~50.4 lb of hammers matters more than knives or a 2-year warranty.
- + 16″ of travel is enough to sneak past posts. Banks still belong on a VAM, not this H.
The actual split
Can a 30 HP tractor run the NAM72H?
No on the published sheet. NAM72H starts at 45 PTO HP (7.5 HP/ft). FM-78H starts at 30 (5.14 HP/ft). A 30–40 HP compact that can lift 804 lb is inside Woodmaxx’s band and outside MechMaxx’s. That is the first fork, before warranty or Y-blades.
Above 45 HP the fork changes. NAM72H is cheaper by about $1,621, 2″ wider, and heavier on the rotor (~50.4 lb vs ~40.7 lb). FM-78H still owns knives, slip clutch, PTO-edge geometry, and two years of parts coverage.
16″ of NAM travel is not FM-78H PTO-edge
NAM-H slides 8″ left or 8″ right. Woodmaxx H publishes cut-edge from the PTO, and the pair of numbers flips when you shift left versus right. Subtracting 16 from 57 is not a comparison. Neither deck tilts.
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| Spec | FM-78H | NAM72H | Edge |
|---|---|---|---|
| Published HP floor | 30 PTO HP | 45 PTO HP | FM-78H |
| HP per foot at floor | 5.14 HP/ft | 7.5 HP/ft | FM-78H |
| Offset unit | Cut-edge vs PTO (asymmetric L/R) | 8″ L or R slider (16″ total travel) | FM-78H |
| Total hammer mass | ~40.7 lb (22 × 1.85) | ~50.4 lb (28 × 1.8) | NAM72H |
| Tilts? | No. Level side shift only. | No. Level side shift only. | Tie |
FM-78H has owner hours. NAM72H mostly has a spec sheet.
Green Tractor Talk owners of the 78H split. One May 2023 report: factory belts too tight, first-use failure, Woodmaxx sent parts, owner would buy again, hammers in 12″ grass almost looked like a finish mower. Another October 2023 report: rusty slide rod on arrival, slide rebuilt within a year, tensioner seized, skids ripped turf, owner wished they had bought a brush hog. Woodmaxx still fixed the hardware.
NAM72H does not have that written chorus yet. Treat brand-level MechMaxx H shopping talk as positioning, not as a 72″ field test. The 45 HP floor, 16″ slider, and ~50.4 lb hammer pack are the citable facts until SKU-specific threads catch up.
Spec sheet
FM-78H vs NAM72H specs
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| Spec | FM-78H | NAM72H | Edge |
|---|---|---|---|
| Cutting width | 70″ | 72″ | NAM72H |
| PTO HP range | 30-65 | 45-85 | FM-78H |
| Hitch | Category 1 | Category 1 | Tie |
| Machine weight | 804 lb | 745 lb | NAM72H |
| Shipping weight | 1000 lb | 871 lb | NAM72H |
| List price | $4,620 | $2,999 | NAM72H |
| Price per inch of cut | $66 | $42 | NAM72H |
| Warranty | 2 years | 1 year | FM-78H |
| Side shift | Hydraulic (no tilt) | Hydraulic (no tilt) | Tie |
| Rear remotes required | 1 | 1 | Tie |
| Blade options | hammer, y-blade | hammer | FM-78H |
Driveline and hammers
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| Spec | FM-78H | NAM72H | Edge |
|---|---|---|---|
| Rotor diameter | 5″ | 5″ | Tie |
| Rotor RPM | 2,160 | n/a | Tie |
| Blade tip speed | 95 mph | n/a | Tie |
| Hammer setup | 22 × ~1.85 lb | 28 × ~1.8 lb | NAM72H |
| Total hammer mass | ~40.7 lb | ~50.4 lb | NAM72H |
| Belt drive | 3× BX39 (Gates Truflex) | 4× V 17x991 | Tie |
| PTO protection | See manufacturer | Shear-bolt (published) | Tie |
| Cutting height | 0.75″-3.75″ | 0.6″-2″ | Tie |
Woodmaxx FM-78H strengths and tradeoffs
Utility-tractor owners who want wide coverage and offset control in one deck.
Pros
- Width plus hydraulic offset in one implement
- Built for heavier grass and brush workloads
- 2-year parts warranty
Cons
- Premium over FM-78 for the H package
- Requires rear remotes and adequate ballast
MechMaxx NAM72H strengths and tradeoffs
Utility tractors that need wide open-acreage mowing plus modest hydraulic offset around fences and trees.
Pros
- 72″ cut with 8″ left/right hydraulic side shift
- 28 heavy 1.8 lb hammers and four 17x991 belts
- Lower direct price than many premium side-shift flails
Cons
- Manufacturer 3″ material statement is a claim, not a tested result
- Requires one rear remote and adequate lift for a 745 lb mower
- No ditch-bank tilt and no Y-blade option listed
Owner signal
What owners report about FM-78H vs NAM72H
FM-78H
Themes paraphrased from Green Tractor Talk (May–Oct 2023), TractorByNet (2019), and Woodmaxx product-page reviews (retrieved 2026-08-14). Not a scientific sample.
- Factory belt tension on first use. A GTT owner of the 78H reported a first-use failure from belts set too tight at the factory. Woodmaxx sent parts after some back-and-forth; the owner had already bought bearings and belts. They still said they would buy it again.
- Hydraulic slide and rust on arrival. Another GTT owner (Oct 2023) said the slide rod arrived rusty, the hydraulic slide fell apart within a year, and the metal-to-metal tensioner pivot seized and ate belts. Woodmaxx resolved the issues promptly. That owner still wished they had bought a brush hog instead.
- L3901 and L4802 pairings. Woodmaxx-page reviews describe the 70″ H as workable on Kubota L3901 and L4802 when lift and one remote are sorted. One L3901 owner said it used less HP than a 5-foot rotary and would not go larger.
- Locust and pasture cleanup. A June 2026 Woodmaxx-page review from a 60-acre horse and cattle place said bristly locust stayed down 1 to 2 years after flail passes, versus growing back by the next cut with a rotary.
- Skids, grass piles, and winter ballast. GTT notes include lifting the deck on turns so skids do not rip turf, and dumping built-up grass. On TractorByNet (2019), one owner left the FM-78H on the tractor all winter as FEL counterweight.
NAM72H
Themes are editorial interpretations from manufacturer-published specs and brand-level MechMaxx hydraulic flail shopping discussions (retrieved 2026-08-14). SKU-specific written owner volume for NAM72H remains thin versus NAM68H and FM-78H.
- Wide affordable side shift. NAM72H combines 72″ width with hydraulic travel at a value-oriented direct price.
- Rear remote requirement. One rear remote pair is mandatory for the H feature and may add tractor setup cost.
- Manufacturer material claim. Thicker-material statements are treated as manufacturer claims rather than verified field performance.
- KDK step-up path. Buyers with Cat 2 tractors and heavier-duty needs should compare KDK rather than forcing NAM-H beyond its role.
Final call
FM-78H vs NAM72H: which should you buy?
Choose the FM-78H at $4,620 when 30 PTO HP, Y-blades, or published PTO-edge reach is the constraint. The name is 78. The cut is 70″.
Choose the NAM72H at $2,999 when 45+ PTO HP is already on the tractor and you want the extra 2″ plus ~50.4 lb of hammers. One remote. No tilt. Written owner volume for this SKU is still thin.
FM-78H vs NAM72H FAQ
Can a 30 HP tractor run the NAM72H?+
No on the published sheet. MechMaxx lists NAM72H at 45–85 PTO HP. The FM-78H lists 30–65. If you only have about 30 PTO HP, this pair is not a toss-up. NAM72H is out.
Is NAM72H 16″ of reach the same as FM-78H offset?+
No. NAM-H is 8″ left or right of slider travel (16″ total). Woodmaxx H numbers are cut-edge from the PTO, and they change when the deck is shifted left vs right. Do not subtract them as if they were the same unit.
Which has more hammer mass, FM-78H or NAM72H?+
NAM72H. It lists 28 hammers at about 1.8 lb each (~50.4 lb total). FM-78H lists 22 × ~1.85 lb (~40.7 lb). Do not buy FM-78H as the heavier steel hammer pack in this pair.
Does either deck tilt for ditch banks?+
Neither. Both stay level. Banks are MechMaxx VAM, grass-only, two remotes. See VAM65 vs FM-78H if tilt is the job.
Is the FM-78H worth about $1,600 more than NAM72H?+
The list gap is about $1,621 ($4,620 vs $2,999). That money buys a 30 HP floor, Y-blade order option, slip-clutch path, published PTO-edge geometry, and a 2-year warranty. It does not buy more hammer mass or a 72″ cut.
Woodmaxx FM-78H vs MechMaxx NAM72H: which should I buy?+
Buy FM-78H if you need a 30 HP floor, Y-blades, slip clutch, and a 2-year warranty on a 70″ (name ≠ cut) deck. Buy NAM72H if you have 45+ PTO HP, want 72″ plus a cheap 16″ slider, and accept hammer-only blades and a 1-year warranty.