Calculate the total torque applied to the nut. This would be the force multiplied by the extended length. I just don`t see how the length of a torque wrench can impact a calculation that needs to be adjusted for expansion away from the pivot point that provides additional leverage. I see that the measured setting of the torque wrench will be lower with an extension and I have to say that when I sat down and thought about it, I came to Torque (specified) = torque (key) x (1 + extension length in meters – which is the simple formula you said was wrong. My example is that I try to apply 50 Nm torque to a nut, but I have to use a crow`s feet that removes the 50 mm torque wrench from the pivot point. I thought that the setting of the torque wrench already took into account the maximum torque (i.e. the 50 Nm setting) at the socket of the torque wrench, which means that it takes into account an infinite number of lengths and only means that the force exerted at these lengths varies to appear when 50 Nm are reached at the socket. If the setting is in Newtons per meter, why can`t I just add the extra distance between the output and the pivot point (in meters) to one meter? This way I would apply 50N x (1m + 0.05m) = 52.5Nm – Ops too! Changing the expression to Torque(wrench)= Torque(specified)/(1+ Extension length) to get a torque wrench setting of 47.6 Nm seems correct. Am I missing something or is it really that simple? One. For anyone who has read this and is still confused, Ted Mooney knows what he`s talking about. His last two posts, and especially the penultimate post, should help many people who seem to get stuck on the force exerted on a torque wrench. Many people confuse the operation of a lever arm on a torque wrench. What people think is that if you increase the length of the handle and apply the same amount of force to that extended length, you get a higher torque.
While this is the right logic, it`s not the way a torque wrench works. A torque wrench is set to a certain torque, so if you increase the length of the handle, you just need to apply less force for the torque wrench to “break”. They are not only exerting the same force on the grip that some people have assumed. You can use the forces to release the new torque, but you have to remember that the force you apply will change, NOT the value to which the torque wrench is set. In my situation, I have a 5.75″ long torque wrench, and the crow`s feet adds 0.75,” so the total lever I have on the BOLT is 6.5.” My torque wrench is set to 55 lbs. So if I use my torque wrench normally (with a jack, not a crow`s feet), I need to apply 9.56 lbs to the end of the handle to reach the breaking point of the torque wrench. (F = 55″ lb / 5.75″ = 9.56 lbs). I wanted to know how much torque I was applying to the screw when I added the crow`s feet extension, so here`s what I did. (T = 9.56 lbs * 6.5 in = 62.17 in- lb) Since I always apply 9.56 lbs at the end of the handle and the torque wrench will still break at this point, the new torque at 62.17 lbs is higher due to the longer lever arm on the screw.
So to bring the torque applied to the screw back to 55 lbs as I wanted, I can basically work backwards from that logic. If I want 55 lbs and my lever is 6.5 inches from the torque wrench handle plus crow`s feet, the force I need to apply to the end of the handle is now 8.46 lbs (F = 55″ / 6.5″ = 8.46 lbs). Now that I want to apply exactly 55 lbs of torque to the screw, I need to apply exactly 8.46 lbs of force to the end of the handle; To make sure I don`t put more force on the end of the handle, I need to adjust the torque setting on the torque wrench so that it breaks at that time. So I determine the torque setting required for the wrench using the force I just found and multiplying it by the length of the torque wrench. (T = 8.46 lbs * 5.75 in = 48.65 lbs). So I set my torque wrench to break at 48.65 lbs, but it applies 55 lbs to the screw, which is exactly what I need. Remember that your torque wrench has a percentage of errors that the manufacturer should tell you, so don`t expect to get exactly the same result every time, but with the right calculation, you can determine which setting you should use. And I`m sorry that maybe wandered a bit and I wasn`t very clear – I`m an engineer, not a person who knows English. Just draw it and make sure you use your units in your calculations to make sure they work properly. ** One last remark, torque is easy to measure and that`s why we use it to attract specifications, but in reality, CLAMPING FORCE is the specification we`re actually looking for when determining how close we want our connections to be.
It`s just that measuring the clamping force is much more difficult than measuring the torque we apply to the fastener, so be aware that you can use the same torque for two different fasteners, but if one has less friction, you will apply more tightening force to it and it will be tighter. Just a few things to think about and something to keep in mind if you`re serious about tightening. A. Oops. The translation model can only work in a situation of pure rotation. .
