TMK · Tree shear

TMK TMK 300

Name: TMK TMK 300
Brand: TMK

310 kg shear for 6-20 t excavators — 250 mm hardwood, 300 mm softwood, and the difference matters.

5 published specifications

Positioning

Where this machine sits

The TMK 300 is a compact shear at roughly 310 kg for 6-20 tonne excavators, and its published specification does something unusually honest: it states different capacities for hardwood and softwood — about 250 mm and 300 mm respectively.

That distinction matters more than the numbers themselves. Most attachments publish a single maximum diameter, which is necessarily derived from favourable material. Publishing two figures acknowledges that Australian hardwood is a materially harder cutting problem than softwood, and a buyer working eucalypt should read every single-figure rating in that light.

Published figures

Specifications

Indicative published manufacturer and distributor information. Confirm every figure, lift chart and hydraulic requirement with the manufacturer or authorised dealer before purchase.

Bare attachment weight	~310 kg
Carrier class	~6-20 t excavators
Hardwood capacity	up to ~250 mm
Softwood capacity	up to ~300 mm
Hydraulic flow	~50-150 L/min depending on cylinder arrangement

Interpretation

What the published figures actually constrain

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.

Published figure	What it means commercially
~250 mm hardwood, ~300 mm softwood capacity	The same blade, two materials, a 50 mm difference. For Australian work the hardwood figure is the one to plan against, and it is a useful check on how other manufacturers' single figures were derived.
~310 kg on 6-20 t excavators	A wide carrier range because the attachment is light. The lift chart still governs — a 6 tonne machine's chart is small, and green material at 250 mm is not.
~50-150 L/min depending on cylinder arrangement	A broad flow range that accommodates many carriers, with the arrangement determining where in the range a given configuration sits. Confirm which arrangement is being supplied.
Bare attachment weight quoted	Coupler and rotator weight is additional and must be deducted from the lift chart separately. 'Bare' is the honest way to quote it and the easy way to under-count.

Before it fits

The four checks that decide whether your carrier can run this

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.

Check	For this attachment
Mass the carrier must control at reach	~310 kg bare — coupler and rotator are additional and must be deducted separately. On a 6 t carrier the usable working diameter is well below the shear's rating.
Continuous hydraulic flow	~50-150 L/min depending on cylinder arrangement. Establish which arrangement is being supplied before matching.
Working pressure	Confirm pressure at the flow the supplied arrangement needs.
What usually binds first	In Australian conditions, the ~250 mm hardwood figure rather than the 300 mm softwood one — and below that, the carrier's chart.

Commercial fit

Where this machine earns its cost

Right machine when

Mid-size vegetation and clearing work on a common 6-20 t excavator
Contractors who need a light attachment that barely touches the lift chart
Mixed work where the same carrier changes attachments through the week

Wrong machine when

Hardwood stems regularly exceed 250 mm
Sustained high-production felling, where a dedicated machine wins

Before you sign

Verify these for this specific model

Beyond the standard buying criteria for the class, these are the questions this machine in particular raises.

Which cylinder arrangement is quoted, since flow requirement varies with it
The hardwood figure, not the softwood one, for Australian conditions
Blade sharpening interval and replacement cost in stringy eucalyptus

Running cost

What drives the cost of owning this machine

A light attachment on a small carrier is the cheapest entry into mechanised clearing, and its economics are the carrier's economics: a 6-20 tonne excavator earns across clearing, civil, drainage and general work rather than in one task.

Blade and pivot wear scale with material hardness. On eucalypt the attachment works harder than a softwood-derived figure suggests, and consumable budgets should reflect that.

The commercial question at this size is usually own versus hire. An attachment used weekly should be owned; one used a handful of days a year generally should not.

In practice

Ownership considerations in Australian conditions

Plan against the hardwood figure

In Australian conditions the 250 mm hardwood capacity is the relevant one. Treat single-figure ratings from other manufacturers with the same scepticism.

Add coupler and rotator weight to the chart deduction

The 310 kg figure is the bare attachment. Everything between it and the boom also has to be deducted from the lift chart.

Confirm which cylinder arrangement is quoted

The 50-150 L/min range reflects different arrangements. Establish which one is being supplied and match it to the carrier's continuous auxiliary flow.

Questions

Common questions about this machine

Why do hardwood and softwood capacities differ?

Because density and fibre structure change what it takes to sever a stem. Australian hardwood is substantially denser than plantation softwood, so the same blade and cylinder force reach their limit at a smaller diameter. Publishing both figures is more honest than a single number, and it is a useful reminder that a single-figure rating from any manufacturer was derived from some particular material.

Can a 6 tonne excavator really use this shear?

It can carry the attachment; whether it can do the work is a lift-chart question. A 6 tonne machine's chart at reach is small, and green hardwood at 250 mm is heavier than it looks. Run the chart with the shear, coupler and rotator weight deducted at the reach the job needs — on a small carrier the answer is often that the useful working diameter is well below the shear's rating.

Should I own a shear this size or hire one?

Own it if it works weekly — at this capital level it pays back quickly on regular use, and having it on the machine lets you quote work at short notice. Hire it if clearing is occasional, because an attachment used a handful of days a year carries capital cost daily and earns on very few of them, and hire converts it into a job cost you can pass through.

Same class

Alternatives to compare against

Other tree shears covered in this guide.

OMEF

Big Inch BI300

420 kg shear for 8-14 t excavators, 300 mm published maximum cut — the regrowth and fence-line workhorse.

OMEF

Big Inch BI500

1,810 kg shear for 23-30 t excavators with 600 mm published maximum cut.

OMEF

Big Inch BI600

2,400 kg shear for 30 t+ carriers needing ~250-300 L/min — a different category from compact shears.

In service

Fleet packages that use this class

Package D

Commercial land clearing

A deliberately flexible attachment-based system. Instead of owning six specialised purpose-built forestry machines, the same base excavator generates revenue across civil earthworks, demolition, vegetation clearing, log handling, tree removal, stump removal, road construction and drainage.