A question about torque screwdrivers

[HappyHippyDad]

I have been umming and arghing about a torque screwdriver for some time but have not yet bought one.

My fears are the following:

1. There are set torque settings that conductors in a consumer unit should adhere to. However, in the neutral bar which are screw terminals I tend to screw a 6mm in tighter than a 1mm (for example), as if you screw in a 1mm too tight it can shear. You can screw in a 6mm pretty much as tight as you can without fear of it going through the copper. I cant see how a torque screwdriver distinguishes between a 1mm and 6mm. Does it? Does it need to?

2. Are torque screwdrivers always accurate? If I use my normal screwdriver I have a 'fairly', if not 'very' precise feel for how tight I have made the connection. This experience will only improve over the years and you will make varying degrees of tightness as required. You lose this with a torque screwdriver and put all your trust in the mechanism.

I wonder if a torque screwdriver may not be a good option for someone who knows how to use a screwdriver properly? However, I am very much open to persuasion hence the post.

 

[Midwest]

One last thing about this..

Do you have to send off your screwdriver to be calibrated or can you buy some sort of calibrating tool to do it yourself?

There's various online places, that'll be willing to take your hard earned cash. Personally I would overly worry, until there's some mandatory or requirement thing, like with MFT's & Schemes.

Perhaps once in a while, but then I'd probably buy a new, and sell the old one to someone on here

 

[Megawatt]

One last thing about this..

Do you have to send off your screwdriver to be calibrated or can you buy some sort of calibrating tool to do it yourself?

I guess send it of probably once a year I haven’t found one yet

 

[Andy78]

One last thing about this..

Do you have to send off your screwdriver to be calibrated or can you buy some sort of calibrating tool to do it yourself?

If you go for Wiha you can buy this .....

View: https://www.youtube.com/watch?v=kKqw24JQdD4

 

[Mike Johnson]

How do you get the calibration tool calibrated? . A snip at £130.00.
[automerge]1583705818[/automerge]
Anyone have one of the torque check device's and can confirm what driver is needed to use it, I know it comes with them, but wanted to know if it can be used with other torque drivers.
[automerge]1583705974[/automerge]
Looks like an Allen key on the end, and also looks as though it only checks at 2.8Nm.

 

[Mike Johnson]

Or we could club together and buy one of these: Mecmesin | Torque screwdriver check calibrator - https://www.mecmesin.com/software-controlled-torque-systems/torque-screwdriver-check-calibrator I have no idea how much one would cost, but I assume it would not be cheap.

 

[Megawatt]

Or we could club together and buy one of these: Mecmesin | Torque screwdriver check calibrator - https://www.mecmesin.com/software-controlled-torque-systems/torque-screwdriver-check-calibrator I have no idea how much one would cost, but I assume it would not be cheap.

I found one that they use to work on firearms and it’s the cheapest yet

 

[billyblade]

The standard that torque screwdrivers are manufactured to (EN ISO 6789:2017) states that the first re-calibration should be carried out 12 months after first use or 5000 actuations (whichever comes first). How many people are going to actually count how many times it has clicked and document it? So 12 months it is.

Anyone who has their torque equipment inspected should be able to produce a valid calibration certificate to prove the calibration has been carried out to the standard quoted above. If they can't, then in theory the torque screwdriver is not being used correctly.

The reason people use one is to prove that they've done everything in their power to install to a manufacturers recommendations with regard to terminal torque settings.

There are many accredited companies around who can calibrate torque equipment. Some of the meter calibration companies have started doing it now too.

It can prove to be quite expensive when you consider the actual cost of the calibration check coupled with possible carriage costs. That's before you take into account the potential for maybe paying for an adjustment too. Many people have said they may as well buy a new torque screwdriver handle instead.

A check tool is a peace of mind thing really. Just to satisfy yourself that your handle is doing what you think it should be. Only a valid calibration certificate will satisfy the standard though.

If you buy a new torque screwdriver most of the time the calibration certificate will appear to be out of date. There are many factors that influence this including time from factory to warehouse, time from warehouse to wholesaler, shelf time at the wholesaler. As I said the first re-calibration should be carried out 12 months after the first use. The date of the first use can be taken as day of purchase (as it can't have been used before then, also assuming that it hasn't been purchased second hand) so therefore if you keep your purchase invoice with the original certificate this should satisfy any inspection and the date on the invoice should be taken as proof of the first possible use, not the date on the original calibration certificate.

Lastly, good working practice should lead you to wind the handle down to its lowest setting when not in use. This releases the tension from the spring mechanism inside and reduces the risk of having to have an adjustment carried out at calibration (if indeed the handle is able to be adjusted).

 

[Mike Johnson]

So who writes the certificate of calibration if you have the Wiha self test unit, are testing certificates available for you to fill them out yourself?

 

[telectrix]

if CU designers were that fussy about torque settings, then they should at least make the terminals so that they didn't cam out before specified torque is reached.

 

[ruston]

if CU designers were that fussy about torque settings, then they should at least make the terminals so that they didn't cam out before specified torque is reached.

This is the problem with low torques, it is not so bad on new equipment, but a bit of crud on old fittings can influence a low torque.

 

[billyblade]

So who writes the certificate of calibration if you have the Wiha self test unit, are testing certificates available for you to fill them out yourself?

It's a torque checker, not a calibration tool. It doesn't really measure and record readings rather it indicates that the torque screwdriver is working correctly. It does not remove the need for annual calibration

Green light for safety – check the functionality of torque tools every day with Wiha Torque QuickCheck

It’s a familiar situation for users. After the recommended period of one year or 5,000 couplings, it’s time to send the torque tool off for…

www.wiha.com

To produce a calibration certificate you need to follow EN ISO6789:2017. There are extensive checks stipulated (including 5 checks at 3 separate settings with the average values recorded).

 

[davesparks]

One last thing about this..

Do you have to send off your screwdriver to be calibrated or can you buy some sort of calibrating tool to do it yourself?

The proper use, care and calibration of precision torque screwdrivers and wrenches is not as simple as it is for test gear.
Ultimately it relies on a precision spring to get the actual torque setting.

Some key points are having the torque device at the correct temperature, always returning it to its minimum setting for storage, operating it a few times before use if it hasn't been used for a while.
Calibration periods are often set by the number of operations rather than by time period.

Any application where torque is actually critical will already be subject to significant checking and monitoring with ever use of the torque device being properly logged against each specific fastener it is used on.

 

[telectrix]

but don't any of you think this is all overkill. next we'll see plumbers having temp.calibrated blowlamps to stop them burning structures, and wood butchers with their hammers calibrated in foot pounds in case they nail a plumber to the floor too tightly..

 

[Moley]

Any application where torque is actually critical will already be subject to significant checking and monitoring with ever use of the torque device being properly logged against each specific fastener it is used on.

We have to go through that on some our jobs. Usually the reconnection on gen transformers or the connections on the main generator breaker. Very often we have the site engineer watching the torquing and noting down the readings against each braid or connection. Some check the torque setting on the wrench at the start and finish of the reconnecting to make sure it hasn't changed. Then comes the ductoring....

 

[Midwest]

On a domestic setting ( see what I did there), who will actually be asking for you to provide a calibration certificate, for your torque screwdriver?