Under the Hood
Under the hood
Denise L. Rondini | Editor | drondini@rrpub.com
Impact vs. Chrome Sockets
Chrome hand sockets and impact sockets have design differences, according to Snap-on. Each is designed and manufactured with specific applications in mind, and they are built to handle that job only. The user must be careful not to use a chrome hand socket on an impact gun. The impact socket has thick walls and is finished in a black phosphate or black oxide finish. Impact sockets also have a cross hole in the handle end for use with a retaining pin and ring or locking pin anvil to allow the socket to be attached securely to the square drive of an impact gun. Power sockets, designed for use with power nut runners, multi-spindle machines and angle head nut drivers, may cause some confusion since they are offered in a black finish. But, they are stamped: “WARNING: NON-IMPACT.” Power sockets are heat treated to a higher hardness than either impact or hand sockets. According to Snap-on, this high hardness, combined with thick socket walls, produces a strong, wear resistant socket. This socket is suited for assembly-line work where it is not subjected to high-impact loads. Hand sockets have a thin wall which allows for clearance in general applications where hand torquing is used. Hand sockets, except for those intended for industrial use, are chrome plated. Although hand sockets and power sockets can fit the impact wrench, they are not the same and must not be used on impact tools. One difference you can’t see between these two types of sockets has to do with the way each has been heat treated and/or the composition of the metal used. The
impact socket made out of medium carbon alloy steel is heat treated to a low hardness range which has been optimized for impact use. This means that under heavy, continuous use, an impact socket will withstand the impact blows and will wear rather than break. Hand sockets are made of medium carbon alloy steel heat treated to a hardness range commensurate with their size and configuration. Hand sockets are heat treated to a comparatively higher hardness for high strength and more wear resistance than impact sockets. But, they are made to sustain hand applied torque applications only. They are not designed for use on impact guns, and should never be used on them. Using only impact sockets on impact wrenches reduces the risk of injury, delays and damaged work. It’s relatively easy to spot a hand socket that’s been misused on an impact wrench, Snap-on says. Check the square drive end for signs of damage and distortion. Cracks and other damage often will appear around the wrench end as well. Breakage due to impact use is considered misuse and not the fault of the hand socket itself. Improperly using hand sockets on impact tools may be hazardous as they may crack. By knowing the difference between the various types of sockets and using them appropriately, you will be able to ensure a safer and more efficient work environment.
Safety Recalls
The National Highway Traffic Safety Administration (NHTSA) has issued the following recalls: Daimler Trucks is recalling certain model year 2010 Freightliner Cascadia trucks manufactured May 20, 2009 through January 29, 2010 and equipped with Sheppard HD94 steering gears. Restraining washer locking tabs may not have been seated into the pitman arm retainer notches during assembly. Incomplete installation of the pitman arm retaining mechanism may allow unthreading of the retainer. Disengagement of
the pitman arm from the steering box may result in loss of steering and a crash could occur. On certain Kenworth model year 2010 T270 and T370 trucks equipped with non-LMS hubs the spindle nut attaching the hub and bearing to the axle spindle (steer or drive) may have been over-torqued during the hub installation process. An over-torque of the spindle nut may cause the bearing to seize, possibly resulting in the overheating of the wheel end. As a result, a wheel-end fire may occur. The spindle and hub will be inspected for scoring and replaced if necessary.
8 | SUCCESSFUL DEALER | August 2010