May 28, 2008
MIT torque wrenches. Click image to enlarge
By Glen Konoroski
Today’s cars are much more complex than their counterparts of just 10 years ago and to work on them confidently special tools are often needed. One of these tools is the Torque Wrench. There was a time when only mechanics had torque wrenches as their cost was exceedingly high and borrowing one made more sense for the home engine builder. Over the past five or six years the prices of these once exotic tools have come down to a price point that most of us can afford.
Your next question is probably, “Why do I really need a Torque Wrench”? If you are a do-it-yourself kind of person who works on newer cars, you will find they are vital in many applications. The reason is that many new cars today use aluminum as the base metal for the engine, or at least the engine’s head. Aluminum is generally softer than steel, so over-tightening the sparkplug (threads are steel) can damage the plughole threads in the head. Some items like knock sensors, if not torqued to the right setting will cause the engine to ping.
A few months ago Boss Tools sent me two of their MIT torque wrenches for testing to try out on an aluminum engine I was working on. The two units they sent were their 1/4-inch and a 3/8-inch inch models. Both units are fairly compact at just 29 cm, unlike the traditional torque wrenches of the past, which measured 38 to 40 cm. The MIT units came in both metric and imperial settings. For the Imperial settings, both units used inch pounds and for the metric settings, the 1/4-inch drive unit use Kilogram-meters (Kpm or mkp) and Newton meters. The 1/4-inch drive unit started at 20 lb.-in. up to 200 lb.-in. and the 3/8-inch drive unit started at 120 lb.-in. up to 960 lb.-in., decent ranges for torque wrenches.
Looking over the wrenches, the quality of the chrome, general makeup, and the stamped numbers (on unit) seemed good. Unlike many torque wrenches I have used in the past operating these wrenches was quite easy and simple. To set these units, you just loosen the lock nut at the bottom and then twist the handle to the right torque setting.
Both of these torque wrenches also have a reverse, so on the rare occasion that there is a reverse threaded nut or bolt they too can be tightened to the right specification.
For accuracy, I marked a nut and then torqued it to a predetermined setting with a recently calibrated professional make torque wrench. In my testing I found that the two units were pretty much on the same mark as the professional high priced torque wrench. So, overall I have to say they are a pretty good value for the money at $39.95 for the 1/4-inch drive unit and $37.95 for the 3/8-inch drive.
Keep in mind that these tools are precision tools and need to be kept in their cases when not in use. Also when not in use, torque wrenches should be slackened off to their lowest setting (that’s why the cases are longer).
One last note when buying a torque wrench: they should come with a case that holds them snugly, giving good protection. This proved to be helpful when one of our test units, while in the case, hit the floor. After a recheck of its condition and accuracy, the wrench was okay.
NOTE: Convert lb.-in. to lb.-ft. by dividing by 12.
Convert lb.-ft. to lb.-in. by multiplying by 12
Convert Nm. to lb.-ft. by multiplying 0.738
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