OMEF TRI pruning cutting bars

Three models, one capacity. The TRI1600, TRI1900 and TRI2200 all cut the same 100 mm class, all run at 60 L/min, all suit 4 to 10 tonne excavators, and differ only in working width and the weight that comes with it: 1.6 m at 240 kg, 1.9 m at 265 kg and 2.2 m at 290 kg. Buyers reach for the largest number on the list expecting more capacity, and on this family that expectation is simply wrong. Correcting it is worth doing carefully, because the money involved is real.

Working width and cut capacity are different things

A comb and shear bar cuts a stem between a moving knife and a fixed finger. The force available at any one finger is set by the drive and the geometry of that pairing, and it is identical on all three models, which is why the published cut capacity does not move with width. Adding 600 mm of bar adds more fingers doing exactly the same work, not stronger ones.

What changes with width is how much of a face is dealt with in a single sweep. That is a coverage figure, and it interacts with the shape of the job rather than with the timber. On an open highway batter, 2.2 m of face per pass against 1.6 m is a straightforward saving: fewer passes up the same batter, fewer machine repositions, more finished kilometres inside a fixed traffic control day. On a corridor punctuated by poles, signs, guard rail ends and driveway culverts, the long bar spends its time being manoeuvred around obstacles and the advantage evaporates, sometimes reversing, because the short bar can be worked into places the long one cannot reach at all.

Weight is the other half of the trade. Two hundred and ninety kilograms is not much for a 4 to 10 tonne machine to lift, but a 2.2 m bar carries that mass spread along a long lever, and when the bar is angled down a batter the load sits well outboard of the dipper. That is a stability question at reach rather than a lifting question at the boom foot, and it is why the widest bar belongs at the 8 to 10 tonne end of the band while the narrowest is the right choice at the bottom of it. Run the numbers at the radius the work actually needs using the lift chart guide, and see the 5 to 10 tonne class page for carriers that hold that position comfortably.

What the 100 mm class actually handles

A hundred millimetres covers several seasons of roadside regrowth, most native shrub layers and the lower limbs of young trees. The shear leaves a noticeably cleaner face than a rotating disc, which matters where the client inspects the finish, as councils and rail corridor managers often do, and it throws far less material, which matters beside live traffic.

Where it struggles is in material that is not uniform. A comb and shear bar is happiest in the sort of even hedge structure it was designed around, and Australian native regrowth is frequently multi-stemmed, leaning and irregular, with dry dead wood in among the green. Individual stems within the class are cut cleanly; a dense clump presenting six stems to two fingers at once is a different proposition. This is the single strongest reason to insist that any demonstration happens on the actual corridor, in the actual season, rather than on a maintained hedge at a dealership.

The mechanical angle adjustment is set before a run rather than changed on the fly. On a corridor with a consistent batter profile that is no limitation at all. On one that alternates between a vertical fence line, a flat table drain and a 1 in 2 batter, it means stopping to reset, so ask whether a hydraulic angle option exists for the build being quoted and what it adds to the delivered weight.

Flow is a figure, not a window

Sixty litres per minute is published as a requirement rather than a range, and it is the specification most likely to disappoint after delivery. A carrier that can produce 60 L/min briefly is not the same as one that delivers it continuously through a hot afternoon, and a bar run at 45 L/min does not cut more slowly in a tidy proportional way; it loses knife speed, and a comb and shear system that has lost knife speed tears rather than shears. The finish goes first and the client notices.

So the question to put to the dealer is not the machine’s maximum auxiliary flow but its continuous flow at working engine speed with the oil hot. Pressure, circuit type, return arrangement and any case drain are not published in our model data and must come from Machinery Specialist for the exact build. Continuous pruning duty also puts steady heat into the oil, unlike digging, so on summer corridor programs read the cooling guide alongside the hydraulic matching guide before committing.

Corridor programs and what they are really buying

Highway and road reserve pruning, rail corridor vegetation inside possession windows, long hedgerows and powerline access track edges are the TRI’s work, and all of it is bought by the kilometre. The pattern on a state road is that the traffic control setup is committed for the shift, so the contractor is selling finished kilometres inside a fixed cost, and pass count is the lever. On rail the lever is the possession: what is not finished when the window closes waits for the next one, which may be months away, so reliability and set-up speed are worth more than an hourly rate. The full linear production model, including how to measure passes and non-cutting time, is worked through on the BF page and applies unchanged here with different inputs.

Cleanup is heavier than with a light bar. Material up to 100 mm does not blow off a shoulder; it has to be raked, grappled or mulched, and on a sealed road it must be gone before the lane reopens. Price it as its own line. Corridor work also frequently sits inside environmental conditions, so check the native vegetation approvals guide for the reserve or corridor in question. See road corridor clearing, rail corridor vegetation and powerline easements.

Neighbours in the range, and consumables

Below the TRI, the BF cutter bar handles 30 mm growth on mini excavators and the TG trimmer handles fine hedge work. Beside it, the BTD disc heads take continuous woody growth to about 150 mm faster but rougher, which is the trade to weigh on a corridor that has been left too long. Above it, the CS pruning heads cut individual limbs one at a time, and material that must be lowered rather than dropped is grapple saw work; the pruner versus grapple saw comparison sets out the test. The mechanical pruning guide covers the ladder as a whole.

Knife sections, comb fingers and the drive are the consumables, plus one item unique to a long bar: straightness. A 2.2 m bar driven into a post, a stump or a rock in a batter can bend, and a bent bar does not cut evenly anywhere along its length. Ask what straightening or replacement costs and how long it takes to get, price a knife and finger kit, and confirm Australian stock with Machinery Specialist against the wear parts guide. Exclusion zones and applicable WHS procedures and manufacturer instructions apply throughout, and the bar’s reach beside a live carriageway is the part to plan around.

Geometry on a real road reserve

Most of the difficulty in linear pruning is not cutting. It is presenting a long bar to a face that keeps changing shape while the machine stands on a shoulder it must not leave.

Three situations account for most of it. Guard rail is the first: the bar has to work above and behind a barrier the carrier cannot cross, which pushes the whole operation out to reach and rewards a shorter bar even on an otherwise open run. Table drains are the second, because the face being cut is below the tracks and the bar must be presented downward without the boom pulling the machine toward the drain. The third is the far side of a batter crest, where the growth that needs cutting is out of sight from the seat and the operator is working on feel and mirrors.

None of that is solved by capacity, and all of it is affected by how the bar is mounted. Settle the bracket, the angle adjustment and any tilt or rotator with the supplier against the actual profiles on the contract, and get the weight of the complete assembly rather than the bare bar, because a tilt arrangement that solves the drain problem also adds mass at the worst end of the lever.

It is also worth planning where the machine stands. A shoulder wide enough to track along comfortably turns the job into a steady walk-and-cut; a narrow one means a sequence of set-ups, and the pass count that looked good in the estimate doubles in practice. Walk the corridor before quoting it, not after.

Confirm before ordering

• Width chosen on obstacle spacing and stability at reach, not on cut capacity, which is 100 mm on all three models
• Stability checked with the quoted bar angled at the working radius on the smallest carrier that will run it
• Carrier continuous auxiliary flow of 60 L/min confirmed with hot oil at working engine speed
• Pressure, circuit type, return arrangement and drain obtained in writing for the exact build
• Oil temperature over a full summer shift assessed before a long corridor program
• Demonstration run on the actual corridor vegetation, not on a maintained hedge
• Angle adjustment type matched to the batter profiles on the contract, with any hydraulic option costed
• Knife and comb finger kit priced, plus bar straightening or replacement cost and lead time
• Cleanup, traffic control or possession windows and vegetation approvals priced separately

Frequently asked questions