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Torque Tests We decided to perform two tests to evaluate how much torque the drills have. High-torque, high-speed applications, such as drilling large holes, are common in all trades. But low-speed, maximum-torque applications, such as driving long screws into wood, are just as important. A good cordless drill/driver needs to be able to do both well.

High-torque, high-speed test.

We used a spade bit to drill 1-1/8-inch holes through doubled-up 3/4-inch plywood to test high-speed, high-torque capacity (see bar chart). Each drill was tested using a new bit, and most drills hogged out between 15 and 25 holes before running out of juice. This test pushed the drills to their limits. Several motor housings became very hot to the touch. One drill, the Ryobi, burned out a battery, although according to the manufacturer, this was probably due to a faulty switch that was drawing too much juice at once. The replacement drill that Ryobi sent performed satisfactorily. Another drill, the Bosch, had some smoke coming out of its motor housing. Boring spade-bit holes at high speed illustrates an important design factor that is never addressed in the manufacturers’ specs. Ads almost always state the overall maximum torque, which a drill achieves at low speed. Yet many high-torque applications, such as boring an 1-1/8-inch spade-bit hole to run pipe, need to be done in high gear. In those cases, the maximum torque of a drill in high gear is very important. Only one drill, the Panasonic, provided this information in its general spec sheet. We had to contact manufacturers to get the spec for all of the other drills. The DeWalt and Makita models displayed the best overall torque at high speed. They didn’t bog down much during our test and maintained good power until virtually the last hole. Although the Makita (28 holes) and Hitachi (23 holes) NiMH-powered models performed very well, as expected, only two NiCad models exceeded 20 holes — the DeWalt (24 holes) and Makita (21 holes). Close behind, the Panasonic and Milwaukee models also performed well in terms of power, although their runtime was shorter. The Hitachi, which bogged down some and seemed to lack the power of these other models, did have very good runtime when equipped with the 3Ah NiMH prototype battery. Overall, most of the drills did okay, but not great. They had enough power to do the job, but were prone to catching and bogging down so that we had to back off and re-engage the spade bit to finish many holes. With frequent use in these types of applications, having a drill bog down a lot tends to jar the user’s wrist. Only the Metabo performed poorly. It lacked power, bogged down often, and was able to bore only 13 holes.

Maximum torque, low speed.

Our second high-torque test involved driving 3-inch long, 1/4-inch lag bolts (without pilot holes) into 6x6 pressure-treated pine (Figure 2) to test low-speed, high-torque capacity. Results from this test mirrored the manufacturers’ self-reported overall maximum torque capacities. DeWalt and Makita, whose ratings are around 330 inch-pounds, clearly had the most power. Most drills with ratings between 275 and 310 inch-pounds performed fairly well. The Bosch, rated at 250 inch-pounds, lacked power. Bosch hopes to remedy this in 1999 when it comes out with a new and more powerful line of cordless drills, the Blue Rage series (Figure 3).Figure 3. Bosch claims that its new Blue Rage, to be available in 1999, will have much more power than 14.4-volt drills currently on the market.