What is a Torque wrench?
A torque wrench is a tool used to apply a specific torque to a fastener such as a nut or bolt. It is usually in the form of a socket wrench with special internal mechanisms
In addition to mounting tools, a torque wrench is mainly seen as a measuring tool.
According to ISO standards 6789-2:2017 calibration should happen every 5000 operations or every year, whichever comes first.
The use of a torque wrench is similar to working with a traditional ratchet with socket or a wrench.
In contrast to the use of a normal ratchet with a socket, a wrench and / or spanner, it is possible to accurately apply the tightening torque of a bolt when using a torque wrench.
If a specific torque needs to be applied for a job, you can use a digital or a mechanical torque wrench.
As TrackWrench® we prefer to use a digital torque wrench because of its accuracy and less risk of overtoque.
When using a mechanical click-type torque wrench, you will always overshoot after clicking, which means that the bolt is overtorqued.
Especially at low tightening torques the bolt can be overtorqued with 25% or more.
An additional advantage of a digital torque wrench is that it does not have to be turned to zero after use, depending on type 1 or if several pre-sets can be programmed.
Furthermore, digital key offers you the possibility to read saved tightening moments and to save them in document for the customer.
The type of torque wrench used (large measuring range) depends on the tightening torque, activities. where do you want to use for which application are you going to use the torque wrench.
• Make sure to select the proper torque wrench for the job. (always adjust your torque wrench to the torque that will be applied.)
• Make sure that the applied torque is between 30 and 80% of the torque wrench range.
Bolt needs to be tightened with a toque value of 60Nm, best is to use a torque wrench with measuring range between 6.8 -135Nm
How do I operate a TrackWrench® torque wrench?
As TrackWrench® we advise to keep the following points in mind when using torque wrenches
- Should be cleaned and stored properly.
- Should be checked for accuracy regularly.
- Should never be used in a “breakout” situation.
- Should always be stored at it’s lowest setting.
- Many types should be “cycled” before use.
- Should never be used in excess of it’s capacity.
- Should always be pulled on for safety.
- Always hold handle properly.
- Approach final torque slowly and evenly.
- The required torque value should be between 30-80% of the wrenches capacity.
- The wrench selected should be calibrated in the same torque units that are specified.
- Should be calibrated if dropped.
What should I keep in mind when using torque adapters?
If a torque adapter is used, a correction must be made to the torque value set on the torque wrench.
Torque required x torque wrench length Corrected torque reading = —————————————————— Torque wrench length + adaptor length T = Actual torque reading in the service manual L = Torque wrench lever length. This is the length of your torque wrench – center grip to center of drive. T x L R= ——– L + A A = Torque adaptor extention length. R = Corrected torque reading
Note: When using 75 mm for distance “A”torque wrench and torque adaptor must be in line.
If the adaptor is positioned at an angle the torque wrench distance “A”will be decreased.
When the adaptor is at 90degree angle the torque wrench distance “A”will be equal to zero (0).
To tighten an engine’s cylinder base nut to 20Nm, with the torque adaptor, and a torque wrench with a lever length of 410 mm, compute the extension formula as follows:
List of the known formula variables
T = 20 Nm (actual torque specifications) L = 410 mm (Torque wrench lever length) A= 75 mm (Torque adaptor length)
T x L 20 x 410 R= ——– = ———– L + A 410+ 75
Corrected torque reading
T x L 20 x 410 8200 R= ——– = ———– = ——– = 16,90 Nm L + A 410+ 75 485
I am using a crowfoot adapter, does that affect the accuracy?
- Yes it does.
My ratchet head is broken, do I need to re-calibrate if I repair the ratchet head?
- No, repairing of the ratchet head does not affect calibration.
How often should I have my wrench recalibrated?
- According to ISO 6789-2:2017 a torque wrench should be calibrated every 5000 cycles or once a year.
- Should be calibrated if dropped.
What length of cheater bar do I need to get 300 ft. lbs. from a 250 ft. lb. wrench?
- Never use a cheater bar.
- Never exceed the maximum torque of the wrench.
Can I use my 250 ft. lb. wrench set at 5 ft. lbs.?
- No, all our digital wrenches can only be used from 10% to 100% of full scale. A 250 ft. lb. wrench will go down to 25 ft. lbs.
- No, all mechanical wrenches can only be used from 20% to 100% of full scale. A 250 ft. lb. wrench will go down to 50 ft. lbs.
I need to torque 75 ft. lbs., which torque wrench do I need?
Generally use the middle portion of a wrench, so recommend a 150 ft. lb. wrench.
Is there a maximum torque you can apply on a ratchet head?
Yes, the maximum torque that can be applied on a ratchet head depends on the drive size of the ratchet head determined according to ISO 6789 guidelines, see table below: