Dose digital torque wrench need calibration?

[GLode]

I always wondering about digital torque wrench. However I couldn't find detail information for digital one.
This is my question

1. Digital torque wrench is need to calibrating same as click one?

2. What is the calibration period for digital torque wrenches?

3. If digital torque wrench need calibration, where I have to send the digital torque wrench for calibration? and how cost is that?

4. Which one is better in the overall section between digital torque wrench and click torque wrench?

 

[428PI]

Most critical fasteners these days are torque to yield. I wouldn't think you would ever need to calibrate your torque wrenches with these type of fasteners. I've only calibrated a 3/8 Snap On dial torque wrench because it also had some problems with the dial changing so I wanted it checked out. I haven't ever calibrated my other ones in 40 years in the business.

 

[matt_i]

Imo have to decide what you are using it for and how critical it is to be off by 10%....

If you run some type of quality program in manufacturing its typical to calibrate them annually (or more often).

You can do a decent job if you have access to a precision scale, you make a balanced torque arm from flat-bar and hang the appropriate weights at one end while holding the wrench in a vise.

The click-type is good up to the point where the cam-out device is lubricated. Let it get dry and crusty over thousands of hits and it won't read the same. The digital is nice where you have a number of torques to audit which aren't all the same value. If they are in the same general range one wrench can handle them all. Also nice for auditing because you get to write down actual numbers that can be captured as "records" for written proof you are within spec.

 

[seber]

Having designed several machines using the digital readout sensors I know that the beam type including split beam will be more accurate than digital in most cases. The strain sensor used for digital is extremely sensitive to temperature. If you have it calibrated in a 70 degree lab and then use it in an outdoor setting, you will have an error. Also, it is extremely difficult to calibrate using a weight or scale as you must calculate the effect of the weight and distance of the wrench handle. It can be done and I do but it takes some effort.

 

[GLode]

Imo have to decide what you are using it for and how critical it is to be off by 10%....

If you run some type of quality program in manufacturing its typical to calibrate them annually (or more often).

You can do a decent job if you have access to a precision scale, you make a balanced torque arm from flat-bar and hang the appropriate weights at one end while holding the wrench in a vise.

The click-type is good up to the point where the cam-out device is lubricated. Let it get dry and crusty over thousands of hits and it won't read the same. The digital is nice where you have a number of torques to audit which aren't all the same value. If they are in the same general range one wrench can handle them all. Also nice for auditing because you get to write down actual numbers that can be captured as "records" for written proof you are within spec.

Thank you for your advice. So you mean you don't have a problem using up to 10% Accuracy?

 

[matt_i]

Thank you for your advice. So you mean you don't have a problem using up to 10% Accuracy?

Not exactly, it depends on ~your~ application of which we know nothing.

I'm not saying that any particular kind of wrench is +/- 10% but if you can't afford that kind of deviation from nominal then I'd recommend to step up your calibration game.