THE ACREAGE EQUIPMENT FIELD GUIDE
Flail mower replacement blades: what belongs in the kit?
A spare-blade quote should identify the mower’s rotor configuration and every component in the package. “A set of 22” can mean something different from 22 individual cutting pieces. These WoodMaxx examples show how to compare replacement packages before buying a mower or ordering spares, including a hardware discrepancy that needs a written answer.
By Acreage Equipment · Reviewed November 7, 2026 · Specification research, not a field test
THE DECISION IN NUMBERS
Worked kit check: count the parts behind the package name
Published WoodMaxx identifiers and configuration counts reviewed November 7, 2026. The incomplete-box row is hypothetical. Counts describe the documented inventory, not a replacement procedure or permission to convert blade types. Hardware scope remains unresolved until confirmed.
Scroll the table sideways on smaller screens.
| Configuration or example | Identifier or counting unit | Inventory comparison | Question for the quote |
|---|---|---|---|
| FM-62 family, hammers | FM-HB62-SET | 18 individual hammers | Which applicable bolts and nuts are supplied? |
| FM-78 family, hammers | FM-HB78-SET | 22 individual hammers | Confirm exact revision and hardware. |
| FM-78 family, Y configuration | FM-YB78-SET; 22 sets | 44 outer + 22 center = 66 cutting pieces | Does the kit include all three components per assembly? |
| Hypothetical FM-78 box: 44 outer Y pieces only | Not a verified complete kit | 66 − 44 = 22 center pieces unaccounted for | List center pieces and hardware separately before comparing totals. |
Sources for this decision table (5)
- WoodMaxx FM-Series Rev C manual, September 22, 2026 — pp. 31, 40 and 45 ↗
- WoodMaxx FM-62 — replacement-kit titles and blade conversion warning ↗
- WoodMaxx FM-78 — Y component counts and replacement-kit titles ↗
- WoodMaxx FM-HB62-SET — exact replacement-kit identifier and scope ↗
- WoodMaxx FM-YB78-SET — exact replacement-kit identifier and scope ↗
Identify the machine and factory blade configuration
Record the exact model, production year, serial number and installed blade type. The FM-62 and FM-78 pages explicitly say their factory hammer and Y configurations are not interchangeable. A replacement-kit link does not authorize conversion. The kit listings also use 2015-and-newer labels, while the reviewed manual is Rev C dated September 22, 2026. Ask which document and replacement package apply to the machine being quoted.
Separate complete assemblies from individual cutting pieces
The manual counts FM-78 Y equipment as 22 sets. The product page explains that configuration as 44 outer Y pieces plus 22 center blades. That is 66 cutting pieces across 22 assemblies, before hardware. A box containing only 44 outer pieces would leave 22 center pieces unaccounted for in a complete replacement inventory. This arithmetic identifies package contents; it does not say every component must be replaced on every service occasion.
Use the exact kit identifier, not just the mower width
The manual identifies FM-HB62-SET for the 18-hammer FM-62 family and FM-HB78-SET for the 22-hammer FM-78 family. Its Y replacements are FM-YB62-SET and FM-YB78-SET, counted as 18 and 22 sets. Put the identifier and counting unit together on the inquiry. A seller’s phrase “complete set” still needs a component list, especially where its headline says Y-blades but the machine uses three-piece Y assemblies.
Resolve the hardware discrepancy before ordering
Current kit titles describe M14×70 bolts. The Rev C manual’s axle-assembly table lists M14×2.0×75 fasteners. Do not silently choose one or assume a substitute is approved. Send both references to the supplier and request the hardware applicable to the serial number, including nuts and any required washers. The Y table lists 36 washers for the FM-62 family and 44 for FM-78; those are separate items from the cutting-piece count.
Ask how the replacement parts satisfy the rotor requirements
The manual requires matched sets to maintain rotor balance. A similar shape or a matching hole diameter is therefore insufficient evidence for approving a replacement package. Ask the manufacturer to identify the compatible blade geometry, mounting arrangement and matching requirements, including mass where relevant. This is a parts-selection question for the supplier, not a balancing or installation procedure. Keep the service arrangement separate from the parts invoice.
Take the missing items into the seller brief
For a new mower, request its factory configuration and a separately itemized spare package in the same purchase brief. For an existing machine, include its identifying details and the unresolved bolt wording. Ask whether center blades, washers, bolts and nuts are supplied, then obtain the delivered price and availability. Compare the FM-62 or FM-78 configuration pages if blade choice is still open; compare package contents only after that choice is settled.
Take these questions with you.
- Which exact blade-kit identifier and manual revision apply to this model, serial number and factory rotor configuration?
- Does the package contain complete assemblies or individual pieces, including the center blades, washers, bolts and nuts?
- Can you resolve M14×70 in the kit title versus M14×2.0×75 in the Rev C manual and confirm the approved hardware and matched-set requirements?
- What are the delivered package price and availability, and what separate service arrangement would be needed?
Keep these questions with your exact tractor and attachment details.
Use these questions in my seller briefFOLLOW THE NUMBERS
Sources & documentation
Research record reviewed November 7, 2026. Confirm the current manual and the exact revision supplied with your machine.
- WoodMaxx FM-Series Rev C manual, September 22, 2026 — pp. 31, 40 and 45
- WoodMaxx FM-62 — replacement-kit titles and blade conversion warning
- WoodMaxx FM-78 — Y component counts and replacement-kit titles
- WoodMaxx FM-HB62-SET — exact replacement-kit identifier and scope
- WoodMaxx FM-YB78-SET — exact replacement-kit identifier and scope
- WoodMaxx manual index: Models 2025 to current
