The Big Boy: TMK 400

The Big Boy: TMK 400

The TMK 400 or ‘Big Boy’, is the largest and strongest product within the TMK tree shear product family. Weighing 535 kg, this shear was developed to cut down big trees in central Europe. The force behind its strength are the cylinders that allow 400mm of softwood to be sliced smoothly for this 15mm Hardox 500 steel blade.

Despite its nickname ‘Big Boy’ the shear is relatively lightweight, and a great tool to cut down smaller brush as well as big logs. Its strong capsular structure withstands tensions of cutting down the big trees, while still weighing less than 550 kg. The recommended hydraulic pressure is 200-300 Bars, depending on the chosen cylinder.

Other Specifications

  • Excavator size – 10 – 30 ton
  • Opening diameter – 1070mm
  • Max cut – 350mm (hardwood)
  • Wood type – hardwood, softwood, and hedgerows.


There are multiple attachments available to maximise the shears potential and enable optimal performance.  Attachments vary from; fitting plates, splitting blades, heels, linkage and various cylinder options.


With a telescopic cylinder, the TMK Turbo’s smaller cylinder works first, keeping the motion fast. When the smaller cylinder runs out of power, the bigger cylinder takes over and begins working automatically. This allows for a continuous fast motion without sacrificing its strength. This cylinder has a recommended pressure of 200-220 Bars and is an excellent choice when working with tilt rotators when the reduced pressure doesn’t affect the maximum cutting ability.

With the TMK Turbo cylinder, efficiency is increased up to 15%.


This attachment undoubtedly increases the productivity of the shear. The collector works automatically with an open-close motion to the point where the bunch is dropped. When the shear is closed, the collector opens up to the other side of the trees. When the shear is opened again, the collector first grabs the trees firmly in its grip. The collector allows the user to cut down multiple trees in one go, while holding them firmly in its grip, until the bunch is released, enabling fast and comfortable working.

Work is carried out more efficiently as the user is not having to cut down one tree at a time, placing in on the ground, and repeating. Only when the bunch is dropped, one electric line is needed to release the bunch from the grip.

Splitting Blade

This attachment enables users to finalise the trees cut with the shear, without any hassle. The splitting blade attaches to the side of the shear with bolts and works best with bolt-on-blade models when the same shear can load or move the trees.


In all terrains, the heel is an ideal attachment, providing the shear with extra support and reliability. You can safely take support with the shear using this attachment, no matter the size of the machine. The heel attaches to the backside of the shear by bolts, offering good support when moving with the machine.


For more information or enquires about the TMK 400, contact