Contents
Where do torque specs come from?
Torque specifications are determined by the fastener being used. After engineers determine the size and strength for the application, whether the fastener is dry or lubricated, they can calculate the torque specification.
How do manufacturers determine torque specs?
Two types of tests can be run to determine a torque specification: measuring torque and angle to failure and measuring torque and angle to a specific tension. “Torque-angle to tension is more accurate, but it requires some means of measuring either bolt tension or clamp load.”
What happens if you dont torque to spec?
Insufficient torque Engines that are running, tend to vibrate. In the case of insufficient torque, it’s the stud or the bolt itself that suffers all the impact, causing it to shear. Alternatively, the engine’s vibrations can cause the bolt or nut to come undone, displacing the tensioner.
What happens if you dont use a torque wrench?
Too tight and something will break, it may be the thread on the bolt, or much worse the thread on in the hole. Bolts will also break, sometimes leaving a very hard to remove bit in your frame. Not tightenough and it will work loose, and then you know to do it a bit tighter next time.
What happens to threads if you apply too much torque?
Both types, if torqued too much can cause the threading to slightly warp making it very difficult to remove the fastener later. That warping also weakens and changes the holding power of the fastener.
How is run down torque calculated?
The proper procedure is to run the nut or bolt down to maybe half a turn to contact (washer still loose). Measure the torque required just to move the nut the last bit before the nut makes contact, and add that to the total.
How is tightening torque calculated?
Typical Metric and Imperial bolt torques are indicated in the links below: Metric Bolts – Tightening Torques. US Bolts – Tightening Torques….Calculate required bolt torque
- normal dry: K = 0.2.
- nonplated black finish: K = 0.3.
- zinc-plated: K = 0.2.
- slightly lubricated: K = 0.18.
- cadmium-plated: K = 0.16.
What is the torque setting for the Bolts?
US Recommended Bolt Torque
| Size | Recommended Torque | |
|---|---|---|
| Grade 2 | 18-8 S/S | |
| 5/8″ | 73 | 104 |
| 3/4″ | 125 | 124 |
| 7/8″ | 129 | 193 |
Can you use adapters with torque wrench?
A torque wrench adapter can help you work smarter, not harder, as long as you do so correctly. Adapters will affect the torque wrench setting if the distance changes between the fastener and the torque wrench handle. A straight extension will have no effect on the torque wrench setting.
When do torque rules apply to no torque?
Often there are general torque rules, which apply when no torque is specifically mentioned.
What do you need to know about aircraft torque?
Without aircraft-specific torque specifications to follow, standard aircraft torque bolt charts will give you a good way to estimate the amount of torque you’ll need. These charts will help you get very close to proper torque for all your fasteners.
Which is the correct formula for torque and tension?
Accepted formulae relating torque and tension, based on many tests are: M = P x D M = torque lbf.ft 60 P = bolt tension lbf D = bolt dia.ins . Or for metric sizes: M = P x D M = torque N.m 5000 P = bolt tension Newtons D = bolt dia. mm These formulae may be used for bolts outside the range of the tables overleaf.
How is the hold down torque of an injector determined?
The “original” information is derived from a collaboration between the OEM engineers, and the OE component manufacturers. So an injector hold-down torque is determined by the application, the materials, and the ultiate goal. Maybe that bolt could be a lot tighter, but not without cracking or distortion of the injector flange, crushing a seal, etc.