Torque can be regarded as twisting force, i.e. the power is delivered to twist something. This magnitude is the result of applied force on a given distance from a known axis.
Knowledge about how to adjust torque on an impact wrench the torque of your wrench might be necessary to you if the job you’re doing calls for accuracy. Failure to properly calibrate the torque can lead to damaged screws, lugs, and work surface.
Now, you’re probably familiar with torque wrenches and their calibration, but some of us use impact wrenches—and why wouldn’t we? They make menial and repetitive tasks a breeze—so you might be wondering, can you adjust torque on impact wrench?
The short answer is: Yes, but it’s complicated.
The good news is that you can do it still! Hopefully, you’ve got an impact wrench that allows for such changes.
WHY DO YOU HAVE TO SET IMPACT WRENCHES?
Considering that some of these wrenches can deliver up to 150Nm of torque, it would be wise to more or less cap it out in order to avoid accidents; a well-known technique is simply not squeezing the trigger too hard, just a tap to ensure less force is delivered; this isn’t exactly precise, but you shouldn’t need too much precision, else you’d be better of purchasing a different tool.
The implications of inadequate torque vary:
INSUFFICIENT TORQUE
When bolts are loose, they suffer the vibration and impacts of the engine which lead them to shear. Ultimately, they either break down or come undone, displacing the elements and bringing machines down—In the case of a car engine, the tensioner might be displaced, which shifts the tension of the belt and lead to engine damage.
EXCESSIVE TORQUE
Just as harmful. When excessive force is applied, the nylon or plastic of some tensioners or idler pulleys (and the bearings or screw threads of the bolt in question) might get damaged—This becomes more problematic with aluminum cylinder heads, as the threads of the screw in the engine block can get permanently deformed and therefore incapable of attaining the right clamping load.
HOW TO SET TORQUE ON IMPACT WRENCH?
Setting the torque correctly can stop the wrench from shearing a screw as it stops the driver’s bit from turning once it reaches the desired torque inputted by the user.
Now, the catch with impact wrenches is that they don’t have torque control per se, so the only way to more or less calibrate the amount of force delivered is by changing the speed through the speed control trigger/gears.
ADJUST TORQUE ON IMPACT WRENCH — IF THE TOOL HAS THE OPTION
If your tool has a torque control ring, you can switch how much torque is delivered per impact using the numbered dial to switch speed or gears.
Some torque wrenches come with a lot more options, while some have none at all.
ADJUST TORQUE ON IMPACT WRENCH — IF THE TOOL DOESN’T HAVE THE OPTION
There are attachments that fit onto the end of an impact wrench and basically stop the tool from applying more torque than the one you inputted—These are often very expensive, and you might better of upgrading your gear than buying this.
WHAT TORQUE SHOULD YOU SET FOR TIGHTENING THE LUG NUTS
So, leaving nuts too loose means they might come undone, but leaving them too tight means they can damage the condition of the surface; in other cases, they might be too hard to untighten. Ideally, we want to avoid all sorts of complications, and that requires a specific torque range.
The best source for insight on the required torque of your lug nuts is found in the owner’s manual—don’t tighten your lug nuts until you can’t humanly push them anymore.
Each car manufacturer specifies a tightening level, expressed in ft-lb. for every fastener on your car. The common number is 100 ft-lb. obtained easily with a 2-foot-long wrench and 50 lb. of force; the formula for torque is distance times force, so 2 ft. times 50 lb. equals 100 ft-lb.
Mechanics often sport well-calibrated elbows that know the sweet spot, but the tightness of any should fall more or less within a narrow range.
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READ THE MANUAL
Seriously, the torque values aren’t just related to a particular size, so you can’t apply the same torque to all similar fasteners.
Factors such as different in bolt length, materials of parts, whether or not there is a gasket between the parts and the alloys themselves can change the needed torque—Generally speaking, when the threads of a bolt make a lot of friction with the surface, you will require more torque, otherwise you end up with varying clamping force which is far from good.
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EXTRA CONSIDERATIONS
Torque values often assume clean and dry parts; no dirt, rust, or dried sealer, and no oils. In some cases, however, you’re specified to torque with oiled fasteners, so you can’t use the same torque if they’re dry.
If the manual gives you the dry value, but the threads and bolt are oiled, you would be wise to reduce the torque between 15 and 25 percent of their value, considering that the surfaces will decrease friction—some lubes might even reduce friction up to 50 percent of the dry torque!
CONCLUSION
We’re a little shorthanded when it comes to adjusting torque on impact wrenches, but there are still ways to go about it.
You can always eyeball how much you’ve got to pull the trigger to achieve sufficient torque and unless you’re working with the really delicate stuff, you won’t need that much precision anyways.
Getting it right means tightening your bolts/lugs enough as for them not to fall apart, while ensuring they’re loose enough for them to not break or damage the work surface—depending on the work, there might be a multitude of ways of telling whether or not you’ve got enough torque, so you can know when to stop.
Hopefully, this article will help you solve some doubts on the matter!
