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If you are a garage warrior, a fixer of tools or simply a hobbyist, you must have heard about torque wrenches, no? You know the shiny relatives of standard wrenches where you can set the value of force you need to apply on certain nuts, bolts, and screws?
These things are handy when you are tweaking a delicate nut on bikes and fixing spark plugs in cars. The trick is that these wrenches can exert a great amount of force (in perspective of the nut it’s working on) then you could with bare hands. As a result, you get more force but with less of an effort.
The secret, you ask how to use a torque wrench?
It involves the mechanism of a torque wrench. There are torque wrenches with beams, those with hollow construction that relies on turning a dial and “Click” noise and others have a digital method to set the torque. Then you have to turn the ratchet to a clockwise direction. It tightens the nuts.
Turning it in “Anti-Clockwise” direction loosens the nuts and bolts.
This is how a torque wrench works. But do you know How to Use A Torque Wrench to your advantage? This is what I’ll discuss in this piece.
Understanding the Tool – The Dual Scale
Even if you guys are a tiny bit familiar of these tools, you must have seen the scale etched on the hollow tube of the “Click Types,” or the scale underneath the needle on a “Beam-style” wrench. You surely have seen digital readouts on an electric torque wrench, haven’t you?
Well, the scale has dual units etched on it. You’ve got the Foot-Pound and Newton-Meter. Some even have the inch-pound unit too.
The first step towards learning to use this magic tool is to understand how to interpret each unit. Let us get that factor out of the way first.
You see, if you apply 1 foot-pound of torque with any torque wrench, you are basically applying 12 inch-pounds worth of torque.
When calculating Newton Meters, applying a foot-pound worth of torque means you are applying 1.3558 Newton Meters. Yes, fractions are important when you are dealing with delicate nuts and bolts (i.e. with bike torque wrenches).
When it comes to wrenches with inch-pound units, one inch-pound means 0.1129 Nm.
Fixed this in your head?
Okay, let’s convert our Nm torque measurements into ft./lbs. or Foot-Pound. One Newton-Meter worth of torque measures up to be 0.7375 in foot-pound.
So, you can basically convert any unit into whichever “Other” unit you feel comfortable measuring with.
Torque Wrench Calibration Process – Why and How?
When tightening crucial parts of our bikes or automobile, it is vital that we exert the exact amount of force necessary. If you are not precise about it, too much torque can break the nut or spark plug. Too little and the wheels will wobble.
There’s one little thing that I’m not telling you. In addition to applying torque, one needs to measure it correctly. Professional mechanics have great instincts. They can read the torque level by seeing how holds the wrench and turns it.
For hobbyists and amateurs like us, reading and interpreting the scales are the only options. That too “If” it is giving the correct feed.
Well, torque wrenches themselves are subject to loose parts. They need to be maintained and adjusted properly against a set of standards for the correct reading.
This, my friends, is what we call calibration.
As far as Calibration goes, people trust the professionals as they should. But these guys charge a hefty fee. Good news is, you can calibrate torque wrenches at home!
There are two ways you can do this.
You can do “Weight Calibration (which I favor)” or the “Fish-Scale Calibration.” The processes may seem tedious at first. But don’t worry. I, your friend, am here to explain them to you in easy bits.
Weight Calibration 101
Okay, this is not hard but it involves 9 to 10 steps. You’ll need a marker, a torque wrench (obviously), a bench vise, a rope, pen, and a paper.
Got everything you need? Let’s get down to business.
- Have a good look at the wrench. Do you see the drive and its center? Mark the back of the drive at the center with a marker.
- Where do you put your hand while gripping the wrench? Make sure to mark the spot and measure the distance between the mark on the drive and the latest marking.
- Remember the bench vise? Secure the “Ratchet Head” tightly with it. Make sure you don’t touch anything but the head. The handle should be at a horizontal position.
- The next step in this torque wrench calibration method is to set the torque value. Remember the distance we got a bit earlier? Multiply it by 20 and set that many pounds as the value.
- We drew a mark on the handlebar a while back. All you need to do is to dangle 20 pounds of weight (or 9.07KGs if you prefer it that way) from that spot with a rope.
- If everything goes right, you should hear a loud “Click.” If not, then move the weight towards the square on the head. Hey, we all have troubles the first time. Go through multiple times just to see if the spot is right. Once confirmed, mark the spot as well.
- Bring out your scale and measure the distance of the head from the “Click” mark. Note it down. We’ll need it for an equation.
- Okay, guys, we’ll need to find the “True Torque” of the device at hand. To do that, multiply the number we just found with 20 pounds.
- All right guys, math time! We’re going to use a little formula of Ta=TSX(D1/D2). Ta is what we’ll call Torque Applied and TS is torque settings. D1 and D2 are the distance we found way back in between the handlebar and the top square and D2 is the latest distance.
- Do the math, check what you’ve found. Check it several times just to be safe
- There should be a chart with torque wrench settings for your tool. Verify the numbers you have got. Find out if the tool is giving you exact feedback or not.
- If you are lacking or overdoing the Ta part, take it into account and calculate the percentage to apply to the scale. This will help you figure out how to use a torque wrench based on the feedback.
Calibrating The Tool with Fish Scales
The weight calibration can be difficult for people. That’s why there’s an easier way out. You’ll need a bench vise, a calculator, and a fish scale to try this alternate method of calibration.
- The first thing to do here is to set the torque wrench head securely into the vise.
- Then measure the precisely one-foot distance from the head towards the handle and hang a fish scale there.
- Pull on the scale using two fingers. You’ll hear a click for a specific setting. Note the number down
- Now you have the weight of the pull. Find out the applied torque by calculating it with the help of the equation.
- Switch to a different Torque Setting and do it again and calculate the variation.
- Lastly, convert your number into a percentage figure. This will help you measure how far you are off compared to the standards. You need to apply the percentage to the scale while measuring torque for different parts
Before we proceed, let’s do a quick recap. So far, we’ve learned to interpret different modes of the scale of these tools. Then we learned how to calibrate torque wrench at home without spending a dime on professionals. Now, it’s time to go through the motions of handling the device in a project.
How to Use a Torque Wrench in a Project?
Okay, handing these tools while in a project needs some prep work. Also, you need to keep in mind that these devices come in multiple types (three to be precise). That’s why, to cover everything, we’ll tackle this subject in small subsections as we’ve been doing till now. Ready? Here we go!
First Thing’s First – You Need Preparation!
By this I mean, you need a torque wrench first. For me, I’d encourage you to pick from three types that are available. These are The Click Type, Beam Type, and Electric variants with a digital feed system.
If you are wondering, “Where is the “Dial Gauge” type I keep hearing about?” Beam and Dial Gauge Types are the same things.
Here’s a Tip: If you are looking for something sweet and easy, go for the beam types. If accuracy is your concern, “Click” adjustable wrenches are your best bets.
These wrenches are often calibrated for up to ±4% error. It should be good for up to a year or 5000 uses. By now, you should know how to do it yourselves at home without professional intervention. So, we’re good on this front.
A Bit of Studying Always Helps!
Relax! I’m not talking about studying for tests or graduation exams. It’s only the project you are about to undertake.
Pay attention to the specs and torque levels you need to do the gig successfully. Measure the Torque levels with the performance record of your tool. If the current one is able to do the job, fine. If not, change it to an accurate one.
Get a feed on what wrench setting you want for a specific bolt or a nut. You can always find it in either manual of these tools or the bike/car/bulb/any other tool you are fixing.
Certain nuts and bolts require a certain approach. For example, adjusting a ‘Star Pattern” nut requires us to start tweaking from the middle and move the wrench to both sides.
Don’t Oil Nuts and Bolts Beforehand
It’s no secret that these tightening tools falter when it comes to handling damaged or broken nuts and bolts. Damaged threads are the same story. Using this tool on them can make it harder for you to remove the fasteners later.
Very often, people oil or grease these things hoping for a better result.
Take my advice: Don’t.
Use the tool called “Breaker Bar” for these times. Remove the damaged nuts and replace them with newer ones. Then, use these tools for a better result.
How to Use a “Click Type” Torque Wrench?
This is a simple process that can get complicated if you are not paying enough attention. So, take your time and go through these steps in the exact order.
- First, take a “Standard Wrench” and an appropriate socket (one which fits the nut or bolt’s size) and tighten the nuts. These nuts should be well-placed and snugly fit.
- Then, take a “Click Type Torque Wrench” and adjust it to the value recommended for the nut. As I mentioned, you’ll find the specific value in the instructions. Loosen up the adjustable dial beneath. Set the torque and then tighten it again.
- You’ll find fasteners for every nut, bolt, and spark plug. At this point, place the torque wrench handle at the left side with the fastener’s tip covering the bolt.
- You should always turn the tool clockwise. You’ll hear a “Click.” This means the tool is at work. You’ll hear the second click very soon. It means you’ve reached the desired torque level.
- Repeat the process if you have to. Don’t forget to reset the torque level to zero when you finish.
How to Use a Dial Type Torque Wrench?
The process is almost similar. It is easier than using the “Click Types” I mentioned above. So, let’s get to it.
- The first step is the same as with the “Click Types.” You need to tighten the bolts with appropriate sockets and with a standard wrench so that they fit snugly into place.
- Now comes the torque wrench. You need to grip the handle of the tool with one hand. Do it in a way that the handle remains in the center when you pivot. My advice would be not to let the ends of the handle touch the center bar. It helps with accurate measurements.
- Now is the time to connect the tool to the fastener. Here’s where people make the most common mistake of sitting at an angle. You guys should be sitting in straight line with the wrench. This way, you can see the beam straight. As a result, the measurement will be accurate.
- Tighten the nut or bolt in the clockwise direction. Keep an eye on the dial gauge on top. When you reach the recommended torque setting, stop.
- Continue the process if you have to. Once done, reset the torque value to zero.
How to Use an Electric Torque Wrench?
This can be the most complicated endeavor if you don’t know specifics of these tools. With an electric torque machine at the helm, you can apply torque linearly as well as in an angular fashion (for some advanced models). Let’s not make this too hard for us to understand. For all intents and purposes, let’s focus on the “Torque Only” mode.
- Some of these tools come with a voltage specification and a test certificate to make sure that it runs okay. Check those before doing anything else.
- Next thing to do is to plug this thing into a socket and turn it on.
- You’ll notice a control panel with three (some have more) buttons and a screen. You can increase or decrease the torque value, select or deselect angular mode (for some machines) and the rotation type of the wrench. Found it yet? Okay, good!
- You need to fasten the nuts and bolts with normal wrenches. Few of the “Advanced” heavy-duty electric torque wrenches will do that for you too.
- Then, set the torque wrench/machine at the tip of the fastener and turn the control panel on. Some require you to push one single button. The others require you to push two buttons simultaneously.
- Next, set the torque value with the up and/or down buttons.
- Lock the tool, select which direction you want it to turn (in some cases) and press start. The head will start turning. Low-end torque wrenches will require YOU to do the turning part.
- Once you reach the desired level, some tools will play a sound. In other cases, you may have an LED or two that’ll flash green.
- Just so you guys don’t curse me for not teaching you how to use a torque wrench on angled nuts and bolts, you need to adjust the angle before you press start on the control panel. You’ll find the info on the catalog for these tools and the tool you are fixing.
Well, now you know how to use all three varieties of these wrenches. Congratulations! But we’re not done yet.
Top 6 Best Tips for Using a Torque Wrench Properly
Few Notes for the Users!
Follow these steps to use these tools correctly. I know, you guys are pros by now but hey, here are my own set of tips that’ll keep you and your tools safe and snug.
- Always use the torque wrenches on dry nuts or bolts. Using them on wet parts might cause you to lose friction and slip up.
- Torque wrenches (even the expensive ones) are susceptible to damages. Keep them in a storage case to prevent any hazards.
- Torque wrench calibration is important! Always check with the standards for accuracy and be ready to recalibrate. If you don’t know how; seek professional help.
- Don’t keep these tools wet. They’ll lose efficiency over time.
- Always make sure the torque is set to “Zero” after you are done. It reduces measurement errors.
- Before using, loosen and tighten the adjustment nuts. Any debris that might be stuck in there, will fall out.
Wrapping It Up
Phew! If you’ve reached this point, I commend you for being patient. It is a long guide, I admit. But look at the bright side. Now you know, How to use a torque wrench for projects. You are a tad bit wiser than before.
To be honest with you, these tools are not that difficult to use. Although, advanced automatic torque wrenches need some practice. In any case, you just need to know the basics. Also, remain safe while tweaking parts with these things. Hopefully, my notes at the end will help you lot.
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