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Executive Report: Clean winner EHN’s power tool specialist, Phil Mist, is impressed by the performance and environmental friendliness of Partner’s latest disc cutter. Today’s equipment designers have a difficult job, as legislation governing noise, vibration and fuel emissions becomes increasingly stringent. Disc cutters (or, as Partner calls them, power cutters) can be powered by a two or four-cycle engine, but to ensure the necessary spindle speed and sufficient power under heavy loading, designers have traditionally opted for two-cycle options. However, small engines of this type have had a reputation for pollution. The 74cc engine on Partner’s new K750 has a newly designed engine block and pistons to minimise emissions of unburned fuel. The system also scavenges for waste fuel. Partner claims a saving on emissions of up to 70% and a 30% saving on fuel. Like almost every other two-cycle engine before it, the K750’s runs on a 50:1 fuel/oil mixture. The power unit is canted forward, enabling a larger muffler to be fitted, resulting in a huge reduction in noise emissions – Partner claims 25%. A SmartCarb system is said to provide a correct fuel/air mixture throughout the life of the tool, regardless of any abuse it may suffer. This cannot, of course, be substantiated except by long-term continuous use on site, but the machine under test operated at high revs for long periods without any fall-off in performance. Easy starting 74cc, or 5hp, engines can be difficult to pull start. Frequently firing up this size of engine without some mechanical assistance can result in a very tired operator and regular replacement of starter ropes, pawls and springs. The K750 incorporates a low compression starting system, and certainly the machine was easy to start, even without choke. The engine ran smoothly, with its multi ‘V’ belt transmitting plenty power. The starter assembly is sealed to prevent dust ingress, and the three-stage filtration system is efficient. A clear window shows the remaining fuel level. The alloy guard can be adjusted without tools: the operator just presses and pushes to move it to the correct angle. The only potential problem with this type of system is dust, which could cause the guard to jam. The wheel fitting is the standard 20mm bore size but, as on other recent Partner power cutters, there is a removable ring pressed onto the spindle. Personally, I dislike any adaptation of an abrasive machine’s spindle, but Partner assures me that, because of its tight fit, the ring system causes few, if any, problems. Certainly, positioning and tightening a cutting disc was easy and quick. A 300mm wheel fitted to the K750, whether a bonded abrasive or a diamond blade, will give a maximum 100mm depth of cut. In tests on 45Nm concrete, bonded abrasive wheels and low, medium and high quality diamond blades were fitted in turn. Results varied dramatically. The high quality diamond blade was much better and reaffirmed the value of using accessories that suit the material being cut. Springs at the bottom of the front handle and at the underside of the rear handle reduce vibration. In fact, the rear handle feels as if it is virtually isolated from the body of the machine. Tests suggested that the K750, when fitted with the top quality blade, could be used for up to two hours/day by a single operator, according to exposure limits in the Control of Vibration at Work Regulations. Partner’s quoted figures are 3.3m/s2 at the front handle and 4.7m/s2 at the rear, and EHN’s tests did not vary considerably. Partner Dimas is part of Swedish industrial giant Electrolux, which has many strings to its corporate bow. The design and manufacture of disc cutters under the Partner brand forms an important part of that empire and the K750 should maintain its tradition of high performance and quality. • T
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820305 Executive Hire News › Archives › Feb/March 2006 › Executive Report › Clean winner
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