As you well know, diggers come in all shapes and sizes, ranging from tiny ride-on models capable of fitting through an internal doorway, right up to leviathan mining shovels that can weight more than a thousand tonnes. However, for the purposes of this guide, we’ll be looking at construction excavators.
For many plant operators in the Middle East, the choice is automatic. An excavator will weigh 20 tonnes, be painted yellow, and have the words ‘Caterpillar 320D’ written in big letters on the side.
As decisions go, this is not a bad one. “No-one ever got fired for buying Cat,” as World Wide Auctioneers’ Keith Lupton is fond of saying. However, there are far more choices out there.
Firstly, consider the size that you want. Whilst traditional wisdom has it that bigger is automatically better, this is often not the case. The running costs of using a 20-tonne unit, when an eight-tonne midi-excavator would suffice, will quickly eat into your profit and loss. Midi-excavators, such as the Case CX80C, are still highly productive, and can operate in tight spaces.
Your next decision is whether to go for tracks or wheels. Wheeled excavators, known as ‘rubber ducks’ have never been especially popular in the Gulf, but they do have their advantages. Work can be carried out at a much greater speed, and the wheels are much kinder to the ground compared to metal tracks.
As with all tracked machinery, look at the condition of the final drive sprocket. If the teeth look ‘sharp’, the machine is probably in need of some expensive remedial work. Similarly, if the track pads look baggy and loose, the pins and bushings might well have worn out.
Whilst under the machine, check the clearance between the bottom of its guide rollers and the top of the track pins, as well as the front idler. There should be room to extend forward on the excavator’s track frame.
Moving up to the cab, look at the condition of the metalwork. Remember that yellow paint and replacement graphics are cheap, and are often used to mask the fact that the machine has been harshly treated.
Before you jump down from the operator’s seat, check the ring gear for obvious problems such as missing teeth. When you rotate the cab on its turntable and lift the boom arm, feel for any hesitation or roughness.
The machine should obviously not be squirting hydraulic oil, but it also pays to check the model immediately after shutdown to see whether any smaller leaks have revealed themselves.
Whilst looking at the boom and stick, check for cracks and rewelds. Finally, have a look to see whether the bucket is will meet your requirements. Naturally, it can be changed, but at a cost.
