Auto Service World
Feature   October 1, 2013   by Jim Anderton, Technical Editor

SSGM Tool Test

Milwaukee M12 Fuel 3/8" cordless impact wrench and M12

Cordless tools have a chequered history in automotive repair. Nickel cadmium batteries were a major reason, with their low power density and memory effect resulting in tools best left for occasional DIY use. Lithium ion batteries however, have addressed those battery shortcomings; a strong battery, however, isn’t enough for professional use. Pros require a difficult to achieve combination of power, durability, light weight and long battery life. Milwaukee Electric, well known in the building trades, has launched two series of 12V and 18V lithium-ion powered cordless tools that just might change the air-driven paradigm that’s dominated auto service for the last 60 years. SSGM tested Milwaukee’s M12 Fuel impact wrench and M12 ratchet kits in typical automotive service conditions driving a variety of ¼-inch and 3/8-inch deep and shallow sockets.

3/8-inch drive impact wrench

The impact wrench kit ships in a blow molded case with the impact gun, two 12V lithium-ion batteries, and Milwaukee’s base station type battery charger. The 3/8-inch drive unit uses friction ring socket retention and weighs a mere 2.3 pounds with a motor and head assembly barely bigger than the unit’s pistol grip. There is no mistaking this tool, however for a hobbyist’s toy. The anvil type tool uses a light alloy head and rubber bumper just like the pneumatic tools you are familiar with, and is driven by a brushless motor. It delivers up to 3,500 impacts per minute but more importantly features a two range drive control delivering selectable torque at either 17 foot-pounds or 117 foot-pounds. We found this ideal for nut setting small fasteners, then driving home chassis and under hood bolts by simply pressing the mode switch on top of the housing.

Reversing the drive is by a switch that’s thumb activated without removing your hand from the pistol grip and there’s a useful LED lamp that illuminates with a half press of the trigger and stays on for several seconds while you line up the socket. The kit ships with two batteries, but in two hours of continuous use on a variety of automotive fasteners we had yet to resort to the backup. The charger is mercifully simple. There are no switches or complex controls: plug in the battery and wait for the LED to light green indicating a full charge. There is a fuel gauge built into the tool, but with the lithium-ion pack and two batteries, we found it simpler to just run the tool to depletion then snap in a new battery. Overall, the 2454-20 impact wrench is deceptively light and unlike pneumatic tools is neutrally balanced, rather than the nose heavy bias of pneumatic tools. The light weight, combined with neutral balance makes it unlikely that a technician will experience fatigue using this tool.

¼-inch drive ratchet

Also part of the M12 system, SSGM tested the 2456–21 cordless ¼-inch ratchet kit. This kit ships in a zippered nylon case with a similar standalone charger to the 3/8-cordless impact wrench. It uses the same M-12 batteries as the impact tool, and also shares its LED fuel gauge and worklight. Milwaukee has clearly thought about quarter inch ratchet users, as the tool is slim and stick-like with a lever style grip trigger and a ratchet head with the same size, shape and configuration as a conventional quarter inch hand ratchet. No-load speed is 250 RPM and the small tool delivers up to 30 foot-pounds of torque, more than enough for typical quarter-inch drive sockets, but with sufficient feel that you’re unlikely to break fasteners. Like the impact wrench, the tool is neutrally balanced and in this application allows use at arm’s reach and at odd angles; in underdash work with long extensions it was easy to line up sockets and hold the variable speed tool in blind screw setting. It’s possible to lock out the trigger, but we found this feature unnecessary in both interior and under hood use. Like the M12 impact wrench, the tool carries a five-year unit warranty and a two-year battery warranty.

Can these Milwaukee tools work in auto repair environments? The short answer is “Yes,” with the 2456-21 ¼-inch ratchet speeding fussy, multiple fastener jobs such as engine covers, interior trim fasteners and under dash work. Compared to a hand ratchet, it’s notably faster and with its linear design, is far easier to control than a cordless screwdriver. It’s a handy tool, but the 2454–22 3/8-inch impact wrench is a surprise. Despite its small size and slimline battery, the tool is usable anywhere and could replace a 3/8-inch air impact gun in most jobs. It also works at –18°C, which combined with no cord or airline, makes it possible to do quick outside work where necessary. Nobody likes to fight a battery hold down outdoors in a Canadian winter, but this tool not only works in the cold, but can be triggered and reversed with gloved hands. With both these M12 system tools, the battery packs are quick charging and almost impossibly small given their deliverable power. SSGM will continue to test Milwaukee’s cordless lineup.

Look for more coverage of Milwaukee tools in upcoming issues.

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