Shearex HM-70SR / HM-70DR front-mount mulcher

Width against the front end of a loader

The HM-70 is the widest head in the Shearex HM front-mount mulcher range that still belongs on a conventional loader, and the whole page is really about that sentence. At 190 cm it cuts wider than any Shearex excavator mulcher, which is the production argument. At 1,361 kg in the SR build and 1,490 kg in the DR build it sits on the nose of a machine that was not designed around it, which is the constraint. Everything a buyer needs to decide here comes from holding those two facts against each other.

Below it, the HM-60 runs 149 cm on a smaller flow window and is the head for a mid-frame loader. Above it, the HM-70SV keeps 190 cm but moves to 125 hp dedicated carriers and a 25 cm target. The HM-70 is the last step before the carrier, rather than the attachment, becomes the purchase.

Choosing between the SR and the DR build

Shearex publishes exactly one difference between the two: 1,361 kg against 1,490 kg. Width, published target diameter, minimum carrier power and flow window are identical. The letters are not explained in the material available to us, so this is a distributor conversation rather than a data sheet decision.

What can be said commercially is that 129 kg is not a rounding error on a machine already close to its front-end limit. On a large-frame compact track loader with capacity in hand, the heavier build is unlikely to change how the machine works. On a loader at the edge of its rated operating capacity, it can be the difference between a machine that stays planted on a side slope and one the operator learns to be careful with. Settle the build before the mounting plate is made, because that decision fixes the quoted mass, and take the loader manufacturer’s attachment guidance as the governing document rather than the raw capacity number; the skid steer and track loader class page covers the class constraints.

What 190 cm and 20 cm are worth on open ground

Swath width converts into hectares only where the carrier can drive continuously. On a solar site or a cleared easement, 190 cm is 28 per cent more ground per pass than the HM-60’s 149 cm on the same line of travel, and that difference compounds over a week. On a broken paddock with gullies and standing timber, the wider head simply spends more of its day being manoeuvred, and the advantage shrinks to very little.

The published optimal target material diameter of 20 cm is the figure to quote on. Regrowth, woody weeds, wattle and shelterbelt species sit inside it; mature stems do not, whatever the head manages occasionally. Maximum diameter versus production diameter explains why the occasional maximum is the wrong basis for a rate, and it is worth agreeing the finish class in writing at the same time, because a second pass for a fine finish can cost as much as the first.

What 133 to 204 L/min asks of a large-frame loader

Continuous flow of 133 to 204 L/min is firmly high-flow, and a 74 hp machine meeting the published minimum will not supply the top of it: the loader circuit requirements, the case drain, the return path and the cooler pack are set out in full on the HM-60 page, and the same four answers are needed here at larger numbers. What is specific to this head is that the bottom of its window is above the top of the HM-60’s, so a loader that ran the smaller head happily is not automatically a candidate.

Take the loader’s measured high-flow rating in L/min and bar to the hydraulic power calculator before agreeing anything, and read hydraulic matching and hydraulic cooling and heat for the questions that surround it.

Easement, solar and reclamation contracts

The work that suits a wide loader head is solar and wind farm site preparation, powerline and transmission easements on traversable sections, and farm clearing, shelterbelts and orchards where old rows cover large areas. All of these are quoted by the hectare, so the operational discipline that matters is recording production per pass at an agreed finish rather than per shift.

Old fence lines, easement access tracks and rocky paddocks are where a wide rotor finds trouble, because a wider head simply meets more obstacles per pass than a narrow one. That is the practical case for carbide on this size of head, with blades kept for clean green material; blades versus carbide teeth sets out the comparison.

The ground that stops it

A front-mount head reaches nothing it cannot stand next to. Table drains, batters, guardrails, wet flats and steep sidling all belong to an excavator head such as the VM-40SL, and excavator mulcher versus skid steer mulcher covers where each architecture earns its money. Step down to the HM-60 if the loader cannot carry the mass or supply the flow. Step up to the HM-70SV, or to the HM-88LV for more width on the same hydraulics, once a dedicated carrier is available and material regularly exceeds 20 cm.

Mounting plate, harness and consumables

Three items are routinely left out of loader quotes and all three are needed to work: the mounting plate for the specific machine, hoses of the right size for the flow rather than the fittings, and the electrical harness that operates the head from the cab. Get them named on the quote. Then price the consumable set, remembering that a 190 cm rotor carries more tools than the HM-60 and therefore costs more to refit; wear parts to price before buying lists what to ask for, and Machinery Specialist can confirm Australian stock. A loader head also throws dust and fines back over its own carrier all day, so screen cleaning and an engine bay blow-down are daily tasks rather than weekly ones.

Tipping load: the arithmetic behind the weight limit

Loader capacity figures are widely misread, and on a head of this mass the misreading is expensive. Rated operating capacity is a fraction of tipping load, and tipping load is measured with the load at a defined position. A mulching head is not at that position: its mass sits forward of the coupler and its centre of gravity is further out again, so the effective load on the front of the machine is greater than the head’s weight alone suggests.

As an illustration only, treat a head whose mass acts 300 mm further forward than the reference position on a machine where that difference matters: the moment about the tipping line rises in proportion to the distance, so a 1,361 kg head can load the front of the loader like something appreciably heavier. The exact numbers belong to the loader manufacturer, which is why their attachment guidance, not the rated capacity line in the brochure, is the document that governs. Ask for approval for the specific head mass in writing, and ask it for the DR build if that is what is being quoted, since 1,490 kg is a different question from 1,361 kg.

The practical signs of being over-committed are familiar to anyone who has run one: a machine that steers light at the back, that nods under braking on a slope, and that has to be reversed out of soft ground rather than driven out. None of those is a reason to buy the smaller build if the loader has capacity; all of them are reasons not to guess.

Solar and easement programmes: quoting by the hectare

Wide front-mount heads are mostly bought for work that is tendered by the hectare against a construction programme, and the rate has three inputs that a production figure alone will not give you.

The first is block geometry. Long, straight runs let the head work at its swath; small or irregular blocks spend the day turning, and the wider head’s advantage falls away. The second is finish class, which should be defined by residual material height and continuity and agreed in writing, because the difference between a rough knockdown and a fine finish can be a second pass over the whole site. The third is access and staging: a solar site under construction has piling rigs, laydown areas and traffic routes that constrain where and when a mulching machine can work, and time lost waiting is charged to whoever did not allow for it.

Building a tender rate sets out how to assemble those into a number. Record production per pass rather than per shift so the rate can be corrected mid-programme with evidence rather than argument.

What wears on a wide loader head

Two wear patterns are specific to a head of this width on a loader. The first is uneven tooling wear across the rotor, because the outer sections meet obstacles that the centre never sees, particularly along fence lines and against windrows. Rotating or tracking tool positions where the design allows it evens that out and lifts the life of a set.

The second is the skid shoes and the pushbar or wear edge, which on a loader head take the weight of the machine every time the operator lowers into material. Operators who work with the head resting will replace those items far more often than operators who carry the head just clear, and the difference shows in the tooling bill rather than in the production figures. Price both as recurring items; wear parts to price before buying covers what to ask for, and Machinery Specialist can confirm Australian stock on a full 190 cm tool set.

Fines, screens and fire season

A loader head throws dust and fines back over its own carrier all day, and during fire season that matters twice over: a loaded cooler pack raises oil and engine temperature, and accumulated fines against hot surfaces are themselves a risk. Blow down the engine bay and screens at every break rather than at the end of the day, keep the machine’s firefighting equipment serviceable, and observe total fire ban conditions and the site’s own restrictions; fire risk in clearing operations covers the routine.

Confirm before ordering

• SR or DR build settled with the distributor, and the quoted mass matching it, before the mounting plate is made
• Head mass against the loader maker's attachment guidance, not just rated operating capacity
• Loader high-flow rating in L/min and bar, and where it falls in the 133 to 204 L/min window
• Case drain, return line size and cooler pack access, per the HM-60 circuit checklist
• Agreed finish class and whether the rate assumes one pass or two
• Tooling choice for the obstacles a wide rotor will meet per pass
• Mounting plate, hoses and electrical harness itemised on the quote
• Australian stock and price of a full tool set, holders, belt and bearings

Frequently asked questions