Market Report: Power Tools

Geared up for drilling

Hilti’s latest diamond core drilling system is designed for high performance,
ease of use and safety. Phil Mist gives his verdict.

Probably the least developed power tool market, especially in the UK tool and equipment hire industry, is the diamond core drilling category, which includes in particular machines designed for dry drilling. Because of some old fashioned thinking and often a lack of suitable operator training, dry diamond core drills, which are a superb alternative to hammer core drills, are relatively under-used. The damage caused when using a hammer core drill can be substantial and a significant amount of repair work can be required, whereas a dry diamond core produces perfectly round holes without the need for a major reinstatement operation afterwards. Nonetheless, dry diamond core drills still have to make the sort of market impact their performance deserves.

Amongst the manufacturers that include a dry diamond core drilling system in their ranges is Hilti. For many years, the company has produced a three-gear hand-held model, namely the DD 100. Perhaps the only discernable drawback with it for some users is that three gears have often proved to be one too many, as well as raising the price of the machine. Even competent operators rarely change gear on such tools, and if they are given a choice of three, there is even less chance of them making the right decision. Now, however, there is a new simplified model, the DD 110-D. It has two gears but retains excellent features for operator protection and performance. Powered by a 1600watt motor, it can drill up to a maximum of 162mm diameter in bricks, cement blocks or general masonry. The maximum drilling range is 37-162mm, but optimum performance is from 52-112mm.

With speeds of 650 and 1,360rpm, the machine has a double action safety switch to protect the operator from accidental start up, and a service indication system. Weighing only 5.3kg, the DD 110-D which has a large rear handle, and a safety clutch, that operates in the event of a core drill bit jamming, is available in two different versions. One model only accepts Hilti quick-release dry diamond core dill bits (there is a new range available, the HDM-U series, which have 8mm deep laser welded segments), while the second version has a three-jaw chuck to accept other brands of bits and which uses a hexagon shaft for connection to the core drill. The dedicated Hilti version also incorporates a swivelling dust collection nozzle for connection to a suitable dust collection system.

Location device

The HDM-U core drill bits have a crown that can be quickly replaced, helping to reduce the overall cost of purchasing a new core drill, and they have laser welded segments for long life.
A hole-starting aid is available for each diameter. These are fitted into the end of the core drill bit and then used as a location device until the hole has just been started, at which time it should be removed before completing the hole in the usual way.

In hands-on tests carried out for EHN using a 102mm diameter HDM-U core drill bit for drilling into a 10in cavity wall comprising a first skin of cement blocks and a second skin of red brick, it took just under two minutes and 15 seconds to drill both skins without removing either core section from the core drill bit.

One of the advantages of using the HDM-U core drill bits is that their length enables drilling of walls up to 300mm thick without using an extension rod. Many similar bits are only 150mm long and can drill only one skin before the core must be removed.

Testing was undertaken with the DD 110-D connected to a new Hilti vacuum system, the VC 40-U. This wet/dry vacuum cleaner has a capacity of up to 25 litres (or 40kg) depending on the application and the type of material being collected. A second model, the VC 20-U, is to be launched later this year and will have a 15 litre (25kg) capacity. Both are available in 110V only, and have an automatic reversing filter-cleaning system whereby the airflow is reversed three times within just 15 seconds. Manually cleaning the filter, which is located in the machine’s hood and not in the waste collector, takes only a matter of seconds.

Auto-start facility

Both vacuums contain a black rubbish sack which, when full, can simply be removed and disposed of (not emptied and returned to the vacuum). The machines contain an internal sensor to tell the operator when they are full, and the VC 40-U also has a power tool auto-start facility, which requires a 32A power supply. During EHN’s testing, the 102mm diameter hole was drilled in a completely
dust-free manner, which frees up the diamond segments and increases the drilling rate. In addition, virtually no waste dust was produced, giving a better working environment.

Both the DD110-D dry diamond core drill and the vacuum systems are covered under Hilti’s two year no-cost service period, plus a lifetime parts warranty and the manufacturer’s well known repair cost limit system. Overall, these new additions to the company’s power tool line-up maintain Hilti’s standards of quality and performance, and the extra facilities they have represent the very tempting icing on the cake •

T 0800 886 100
W www.hilti.co.uk

Executive Hire News › Archives › July 2008 › Market Report › Geared up for drilling

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