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Hitachi WH 18DL, 18V Cordless Impact Driver Kit
Long runtime, controllable power
Text & photos by Tom Hintz
Posted – 10-31-2006
Hitachi’s new WH 18DL cordless impact driver kit brings class-leading torque, powered by the cutting edge technology of Lithium Ion batteries. Throw in a group of user-friendly features and you have a cordless impact driver with qualities important to everyone from the home woodworker to on-site contractor pros.
Batteries & Charger
The Hitachi WH 18DL comes with two 18V, 3.0 Ah, Lithium Ion battery packs that produce 3-times the operating life of NiCd or NiMH packs of similar voltage. Interestingly, the Hitachi WH 18DL packs weigh about half of the typical NiCd or NiMH 18V packs. That combination of power and reduced weight translates into extended, less tiring use in the shop or on the job.
While predicting runtimes for any battery pack in your shop is impossible because it is directly related to how the tool is used, suffice it to say that during the evaluation, I lost track of when the Hitachi WH 18DL packs had last been charged. Also, there is no “run down” period when less power is available as a pack nears its discharge state. The Hitachi WH 18DL packs run strong right up until it is time to plug in the second pack included in the kit.
Incidentally, the Hitachi WH 18DL Lithium Ion battery packs have an expected 1,500 charge cycles life. Considering the extended time between needed charging, I suspect the Hitachi WH 18DL batteries will be operating just fine long after I am not. Also, the Hitachi WH 18DL packs are backward compatible with Hitachi 18V DMR and DVF3 tools.
The Hitachi WH 18DL kit includes their UC 18YRL fast charger, designed for use with the 18V (Hitachi #EBM1830) Lithium Ion batteries. Typical time to freshen a discharged 18V pack is 45 minutes. The UC 18YRL charger also handles many Hitachi 7.2V to 18V NiMH and NiCd batteries but check the manual to be sure before plugging a pack in.
A pair of LED lights on the face of the UC 18YRL keep you apprised of the battery condition as it goes through the charging cycle. The lights also warn when a pack cannot be charged because it is hot. To help with that problem, the UC 18YRL has a built in fan that accelerates cooling of the battery for charging.
The Hitachi WH 18DL features an industrial-grade two-piece, copper wound motor that puts the oomph behind its class-leading 1330-in-lbs of torque. Since making power also produces heat, Hitachi added an internal fan that continually pumps fresh air through the motor to control operating temperatures. The motor also has user replaceable carbon brushes and even a replaceable armature that will make it a real challenge to wear the Hitachi WH 18DL out.
To make this amount of power easier to control in the wide-ranging situations found around the shop or work site, Hitachi added a two-position power switch (in the handle) that selects between the Power Mode (0-2,600 RPM) and Save Mode (0-2,000 RPM). As the names suggest, battery power is also conserved by using the Save Mode when maximum torque is not required. The variable speed trigger extends that functionality in both power settings.
The impact mechanism has an overall range of 0 to 3200 bpm (blows per minute) and responds to changes in rpm. Even though there is no clutch, controlling the power of the Hitachi WH 18DL is easy because the impact delivery softens sufficiently at lower rpm to make handling smaller fasteners easier.
A cross mounted slider switch above the trigger handles reversing chores. Though out of the way during normal use, this slider is easy to access when needed and has a positive feel to its operation.
To prevent bits from slipping under the force of the impact mechanism, the Hitachi WH 18DL features a ¼” quick connect chuck that accepts a huge range of commonly available bits. The grip on the hexagonal bit is close and positive.
The chuck has a spring loaded, finger-operated collar that makes changing bits fast, secure and tool-free.
Hook and Light
A 5-position belt hook is mounted on the handle near the battery that frees both hands between driving chores. Belt hooks are not uncommon on cordless tools but the Hitachi WH 18DL version is larger with a wider throat than many. That makes it easier to use, but there is an even more unique feature.
Built into the belt hook is an LED work light, turned on or off with pressure sensitive buttons bear its base. The light can be aimed in any of the five belt loop positions to shine it on the spot needed.
The design folks at Hitachi did a good job packaging the Hitachi WH 18DL in terms of size, weight and form. At just 6 3/8”-long and 3.5-lbs, this is not a tiring tool to use despite the abundance of power it contains.
The pistol grip fits the hand well and gives a very good sense of balance even with longer bits installed. The rubber over molds that are strategically placed in the grip areas are both soft and tacky feeling, giving the operator a solid, non-slip grip.
In the Shop
When I evaluate a new tool that process includes as much in-shop use as is possible. Along the way, more specialized tests are devised to address specific features more directly. The Hitachi WH 18DL did very well in each part of this evaluation.
Despite being very comfortable to the hand, the Hitachi WH 18DL delivers its class-leading power with surprising control. The internal balancing act between the variable speed trigger, dual power ranges and the impact mechanism response to rpm make it surprisingly easy to start a fastener and then gradually increase the power applied to drive it. That level of control also makes it possible to drive a wide range of fastener sizes and types without spinning them off.
The surprisingly small overall size of the Hitachi WH 18DL belies the amount of power it possesses while making it easier to use in smaller places and at odd angles. This is an important point in many common assembly and installation situations woodworkers (and DYI’rs) regularly encounter.
The simple but very strong quick-change chuck is a natural choice for the Hitachi WH 18DL and does its job well. Changing bits is easy, quick and secure. Despite repeatedly driving 3”-long lags trying to run the battery down, the chuck never jammed, stuck or did anything but work as expected.
While there is no way to accurately predict the charge life of the Hitachi Lithium Ion packs in your shop, I can say that the time between charges was consistently long enough that I forgot how long the current pack had been in use. Having two battery packs and the quick charger makes charge life a non-issue with the Hitachi WH 18DL unless you forget to put the depleted pack on the charger.
One of the more notable Lithium Ion features is how they maintain their power right up to when they need recharging. There is no decrease in operating power until the last fasteners that pack can handle is driven and the pack suddenly looses its oomph. Once again, technology is extending the usability of cordless tools in our shops.
I have to admit that initially I thought the LED work light might be more eye candy than purposeful. However, in use, being able to not only turn the light on only when needed but to aim it was very useful. Even working inside a cabinet, the additional light from the LED makes it much easier to get the bit locked into a fastener, which means fewer stripped or damaged screws to deal with. Being able to turn the LED off when not in use saves battery power, a feature most other light-equipped cordless tools lack.
The Hitachi WH 18DL is a well built, well-designed tool that brings a wealth of performance and value to the average woodworking shop or contractor work site. With a street price of $299.99 (10-30-2006) for the complete kit, the Hitachi WH 18DL represents an attractive long-term value.
The small size and weight combined with the lots of easily controlled power will make the Hitachi WH 18DL a very useful tool in your shop or on the job. I am constantly finding more uses for the Hitachi WH 18DL than I anticipated.
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