At 3,560 kg and requiring a 27 tonne or larger carrier, the HTH624C 4x4 is a processing head rather than a general harvesting one. The 815 mm butt-saw capacity and 875 mm feed-roller opening describe a head specified for large or awkward stems — heavy softwood and demanding hardwood — where feeding and delimbing are the hard part rather than cutting.
The four-wheel-drive feed arrangement is the defining characteristic. More driven rollers means more control over stems that are crooked, heavy or poorly formed, which is precisely the material that defeats lighter heads. That capability is bought with mass, and mass constrains the carrier it can sit on.
Indicative published manufacturer and distributor information. Confirm every figure, lift chart and hydraulic requirement with the manufacturer or authorised dealer before purchase.
A specification table tells you what the machine is. This is what each of those numbers means for the work you would put it to.
Each of these can fail independently, and passing one says nothing about the others. Weight class alone is the weakest of the four and the one most often relied on.
Beyond the standard buying criteria for the class, these are the questions this machine in particular raises.
Processing heads are consumable-intensive. Chains, bars, delimbing knives and feed rollers are consumed per cubic metre, and abrasive hardwood fibre consumes them considerably faster than softwood. A cost model carried over from pine work will be optimistic in a way that only becomes visible after several months.
Where the mill pays on measured volume, the measuring system is a revenue component. Calibration drift on a high-throughput head compounds quickly, and the calibration regime is worth confirming before purchase rather than after the first reconciliation.
Feed control is where this head earns its capital: time lost re-gripping a poorly held stem is production that does not appear as a fault anywhere. Witness it processing your material rather than a demonstration stem.
A 320-360 L/min requirement at up to 35 MPa is a serious specification. Check the carrier's continuous auxiliary flow and its working pressure at that flow, plus cooling capacity for sustained duty in Australian summer conditions.
Configuration differences within the same head model matter more than differences between brands, particularly where bark has to be removed to a mill specification. Confirm the configuration with contractors running your species.
A 3,560 kg head alters the carrier's lift chart and stability envelope at reach. Run the chart with the head fitted at the geometry your work actually uses before committing to a carrier pairing.
Other harvester heads covered in this guide.
The clearest published case for optimum over maximum: 700 mm cutting capacity, 160-510 mm best production.
Heavier SP head for heavy softwood, crooked hardwood and demanding processing — 800 mm capacity, 250-500 mm optimum.
Excavator-class harvesting head for ~21-25 t carriers, with eucalyptus roller configurations available.
The heavier Log Max head for ~25-30 t carriers — more capacity and feed force, at 555 kg more mass.
The highest-volume softwood configuration, and the one with the greatest exposure to bottleneck mismatch. Either a full-tree chain or a cut-to-length pair, depending on terrain, mill requirements and contamination tolerance.
Thinning rewards manoeuvrability and restraint. The corridors are narrow, the residual crop has real future value, and the largest machine on the market is usually the wrong answer.
Australian hardwood plantation work places very different demands on a head from radiata pine. Feed force, debarking and durability dominate the specification.