There are only three models in the Dipperfox range and they do not overlap much, so this is a shorter decision than most attachment purchases. The single question that settles it is which excavator this attachment is going to live on for the next five years. Carrier class drives everything else: the hydraulic flow available under load, the stump diameter you can attack, the depth you can reach and the mobilisation cost of every job. Choose the model that matches your existing fleet machine rather than buying a bigger head and hoping a carrier appears to suit it.
How each one works
All three stump grinders share one architecture. A replaceable centre screw engages the middle of the stump and draws the head downwards; reversible double-sided blades cut the timber into chips as the body rotates; and a two-speed planetary transmission trades rotational speed for torque when the blades meet root intersections or dense butt wood. There is no lateral sweep. The head is positioned once, bores vertically to depth, and the carrier tracks to the next stump. What separates the models is scale: the size of the bore, how deep it goes, and how much force is behind it.
The SC400 is the compact unit at 190 kg, for 1.5 to 5 tonne excavators, cutting to 400 mm diameter and 590 mm depth with 13,700 Nm of first-gear torque. The SC600 sits in the middle at approximately 320 kg for 6 to 12 tonne carriers, cutting to 600 mm and 700 mm deep with 16,900 Nm. The SC850 Pro is the production model at 580 kg for 13 to 30 tonne machines, cutting to 850 mm and 900 mm deep with 43,000 Nm in first gear.
Carrier class decides the model
- 1.5–5 t: SC400
- 6–12 t: SC600
- 13–30 t: SC850 Pro
Where the difference shows up on site
Carrier class is the decision, not stump diameter
It is tempting to pick by the biggest stump on the worst job you have ever quoted. That is how contractors end up owning an attachment their fleet cannot feed. A 1.5 to 5 tonne excavator cannot supply the 110 to 230 L/min an SC850 Pro is built around, and a 25 tonne machine floated to a suburban back yard destroys the economics of an SC400 job. Start from the carrier you already own and mobilise most weeks, confirm what it delivers on the auxiliary circuit under sustained load, and let that shortlist the model. The excavator class pages and the hydraulic matching guide are the right places to check that before you commit.
Stump capacity and how often you exceed it
The published maximum is 400, 600 or 850 mm. What matters commercially is the proportion of your stump population that sits under it, because anything above is either a repositioned multi-bore job or a different method entirely. Sample fifty stumps on a representative site and plot the distribution. If ninety per cent fall under 400 mm, the SC400 is the right economic answer and the occasional oversize stump is a line item, not a reason to buy up. If your median stump is 500 mm eucalypt with heavy butt flare, the SC400 will be working at its limit all day and the SC600 will pay for itself in cycle time. The maximum diameter versus production diameter guide works through this properly.
Torque, not just diameter, separates the SC850 Pro
The jump from 16,900 Nm on the SC600 to 43,000 Nm on the SC850 Pro is far larger than the jump in stump diameter, and that is the real character difference. Stump resistance is not constant; it spikes at root intersections, in rock-laden soil and through dense hardwood butt wood. Torque reserve is what keeps the head working through those spikes rather than stalling and forcing the operator to back off. On long shifts in road corridor and rail corridor work, that reserve shows up as consistency across hundreds of stumps, not as a faster single cut.
Drilling depth and what the next trade needs
590, 700 and 900 mm are meaningfully different outcomes. If the surface simply has to be clear and plantable, the shallower figure is fine. If a subgrade, a pavement box or a trench line crosses the stump, the deeper bore of the SC600 or SC850 Pro can be the difference between one operation and a second excavation. Decide from the specification for the finished site, not from the stump.
Mobilisation and access
The SC400’s case is not its cutting speed. It is that a 1.5 to 5 tonne carrier fits through gates, travels on a smaller combination, does less damage to lawns and paths, and can work beside fences. That collapses site protection and float cost on council parks and urban vegetation work. The SC600 sits on the sweet spot of Australian civil contracting: a 6 to 12 tonne excavator is big enough to supply real hydraulic power, reach and stability, and small enough to move between sites without permits and heavy float costs. The SC850 Pro needs its carrier to already be part of the project, because floating a 20 tonne machine for stumps alone rarely stacks up.
Attachment mass on the lift chart
190 kg, approximately 320 kg and 580 kg are all modest next to a bucket, but they sit at the end of a stick and the mini-excavator end of the range has the least margin. Check the mass in the exact ordered configuration, add the bracket, quick hitch and hoses, and read it against the carrier lift chart at the radius you will actually work at. The lift chart guide and the lift capacity calculator cover the method.
Choose the SC400 when
- Your core carrier is a 1.5 to 5 tonne excavator
- Access, lawn damage and site protection dominate the job cost
- Most stumps fall under 400 mm
- Residential, landscaping and council park work is the bulk of the year
Choose the SC600 when
- A 6 to 12 tonne excavator is already a fleet staple
- Work spans civil, utilities, agriculture and landscaping in the same year
- Stump counts run to the hundreds across multiple sites
- You need real capability without heavy float and permit costs
Choose the SC850 Pro when
- A 13 to 30 tonne carrier is already committed to the project
- Stumps are large, numerous and worked in long shifts
- Forestry, highway, rail or transmission work dominates
- Torque reserve through root flare and rock matters more than transport flexibility
The numbers that matter
| Model | Excavator class | Attachment weight | Maximum stump diameter | Drilling depth | Carrier engine power | Operating pressure | Hydraulic flow | First-gear torque |
|---|---|---|---|---|---|---|---|---|
| SC400 | 1.5–5 t | 190 kg | 400 mm | 590 mm | 12–35 kW | 110–250 bar | 30–130 L/min | 13,700 Nm |
| SC600 | 6–12 t | Approximately 320 kg | 600 mm | 700 mm | 35–74 kW | 150–250 bar | 65–150 L/min | 16,900 Nm |
| SC850 Pro | 13–30 t | 580 kg | 850 mm | 900 mm | 74–130 kW | 180–350 bar | 110–230 L/min | 43,000 Nm |
All three use the same two-speed planetary transmission and the same wear-part philosophy of reversible double-sided blades and a replaceable centre screw, so the service routine does not change as you move up the range. Dipperfox marketing pages have shown small differences in carrier descriptions between sources, so confirm the current technical sheet supplied with your quotation rather than relying on any summary table.
Running more than one
Contractors with both an urban tree business and a civil arm sometimes justify two heads, and the pairing that makes sense is the SC400 with the SC600 rather than either with the SC850 Pro. The two smaller models cover carriers that genuinely both exist in mixed fleets, and the brackets and hoses are a second, cheaper part of the purchase once the first machine is set up. An SC850 Pro is harder to justify as a second head because the carrier that suits it is usually committed to earthworks rather than available for stump runs. Where a business does run the big head, it is normally because a long infrastructure contract underwrites it and the smaller machine handles everything that does not justify the float.
Cost logic
Illustrative only, with round hypothetical numbers. Assume a civil contractor with 600 stumps a year spread over fifteen sites, and a 7 tonne excavator already mobilised to twelve of them. Assume the SC600 averages 15 minutes per stump including repositioning, for 150 productive hours a year at an assumed internal machine cost of $180 an hour, or $27,000. Now assume the same work done with a smaller head that needs a second bore and repositioning on a third of the stumps, adding an average of 4 minutes per stump. That is 40 extra hours, or roughly $7,200 a year, before any difference in blade wear from working the smaller head at its limit.
Run the same sum the other way for an urban business. Assume 250 domestic stumps a year, none of them on sites where a larger excavator would otherwise be present. If the SC400’s carrier can be floated on a light combination at an assumed $250 a site visit and a larger carrier would cost an assumed $900, that is a $162,500 annual difference across 250 visits, which no amount of cutting speed recovers. On scattered work of that kind mobilisation is usually the largest single term, which is the subject of transport and mobilisation. Use the cost per unit calculator with your own rates.
Decide with these facts in hand
- The make, model and year of the carrier this head will live on, with its lift chart
- Continuous auxiliary flow and pressure available under sustained load, not peak pump figures
- Whether a case drain is required and available, plus coupler and hose sizing
- Diameter distribution across a 50-stump sample, classified by species, flare and soil
- Required working depth set by the next stage of the project, not by the stump
- Attachment weight in the exact ordered configuration plus bracket and quick hitch
- Blade and centre screw pricing, Australian stock position and gearbox service interval
- A timed demonstration on your own hardwood before production rates enter a tender
Frequently asked questions
Which model do most Australian contractors end up with?
There is no universal answer, but the SC600 is the broadest commercial class because 6 to 12 tonne excavators are common in civil, utility and landscaping fleets and remain cheap to move between sites.
Can I run an SC600 on a 5 tonne excavator?
The published carrier range starts at 6 tonnes and the flow range at 65 L/min, so a 5 tonne machine is outside specification. Undersizing the carrier costs production and stability rather than simply being slower.
Is the SC850 Pro just a bigger SC600?
It is a considerably different proposition. Stump capacity rises from 600 to 850 mm and depth from 700 to 900 mm, but first-gear torque rises from 16,900 to 43,000 Nm, which is what sustains production in heavy root flare and rocky ground.
Do the models share wear parts?
They share the same wear-part concept of reversible double-sided blades and a replaceable centre screw, but sizes differ by model. Price the parts for the exact model quoted and confirm Australian stock.
How much does the bracket add?
That depends on your hitch and carrier, and it is not a figure to assume. Ask for the attachment weight in the exact ordered configuration with bracket, hitch and hoses included, then read it against the lift chart.
Should I buy up a size for occasional large stumps?
Usually not. Buying up moves you into a heavier carrier class and a higher mobilisation cost on every job, to solve a problem that affects a small share of stumps. Price the oversize stumps as a separate method instead.
Get a recommendation, not just a price
Send us your excavator model, hydraulic figures, tree species and typical diameters. We will come back with a carrier-matched configuration and a written specification you can compare against any other quote.