Torque Settings

[boltonbob]

Before venturing forth I use a torque wrench to check my wheels, arecent observer told me I was doing it wrong as I only went to one click and should go for two, upt to now I have always arred with both wheels but his comment has me worried is he right? Ta Bob

[Fireman Iain]

As I understand it a bolt or nut needs to be rotating to correctly check the torque. Checking the torque on a bolt without turning it says nothing for the actual tightness of that bolt. This is because of static friction, which needs to be overcome before a fastener will turn. Caused by corrosion, or rough surfaces binding. Using a torque wrench on a static bolt just says is that the static friction is greater than the torque required.

 

If you are torqueing rotating fasteners on a wheel then you would typically use a star or criss cross pattern, rather than tightening in a circular pattern. And yes, you would torque each bolt a minimum of twice, possibly more to ensure they are all even as they snug the wheel progressively onto its hub.

[Ern]

I more or less agree with the above. To answer the question asked, 1 click is enough.

[Coriolis]

I think perhaps your observer meant that it would be better to get 2 clicks of the same 'break'.

 

People sometimes snatch the bar and the wrench 'breaks' and they stop. ..this can leave the nuts looser than intended.

 

Suggest applying the torque in a gentle controlled fashion, back off the pressure, and go for 2-3 repaets. ..this will ensure the nut is properly seated and get closer to the correct torque.

 

There's a lot of waffle spoken about torque, but all you're actually doing is crudely measuring the turning force, which will vary depending on thread condistion, whether lubricated or not, etc. ..the clamping force is actually produced by the tension created when you stretch the bolt / stud, and the stretch comes from the ramp/leverage when you turn the fastener.

 

Given how crude a torquewrench is in relation to the delicate nature of the design calculations, it's not worth getting into a tizz over it. .. my wheel bolts call for (from memory) 86lb/ft, so I set my (calibrated) torque wrench to that, apply a firm nip to all bolts in a diagonal pattern first, then repeat, this time 'breaking' the wrench a couple of times on each bolt. ..not rocket science and worth checking before each departure from home, or maybe fit some of those plastic indicators which will give early warning of a bolt backing off.

 

Pay particular attention to the nearside wheel as it's more likely to loosen than the offside, due to the relative motions of right hand threads and forwards wheel rotation. ..but don't fret over it, do it right and all will be well

[David P]

Look Here

https://www. youtube. com/watch?v=SwVCVbAHGFU

[boltonbob]

Many thanks for your info, feel better already all the best Bob

[Tuningdrew]

Look Here

https://www. youtube. com/watch?v=SwVCVbAHGFU

Water suitably unmuddied

[Coriolis]

What an excellent video!

 

A picture's always worth a thousand words. ..good stuff

 

Tiny nitpick. ..our friend is mixing up studs with bolts (disregard, it comes from 25 years in aviation quality assurance )

[David P]

Tiny nitpick. ..our friend is mixing up studs with bolts (disregard, it comes from 25 years in aviation quality assurance )

To clarify your understanding, A bolt screws into a threaded hole in a surface. A stub protrudes from a surface with a thread upon it. A Nut can then be threaded onto said stud or bolt! You do the QA bit and leave the work to us Aircraft Engineers (retired) LOL

Edited February 11, 2017 by David P

[Stevan]

As I understand it a bolt or nut needs to be rotating to correctly check the torque. Checking the torque on a bolt without turning it says nothing for the actual tightness of that bolt. This is because of static friction, which needs to be overcome before a fastener will turn. Caused by corrosion, or rough surfaces binding. Using a torque wrench on a static bolt just says is that the static friction is greater than the torque required.

 

If you are torqueing rotating fasteners on a wheel then you would typically use a star or criss cross pattern, rather than tightening in a circular pattern. And yes, you would torque each bolt a minimum of twice, possibly more to ensure they are all even as they snug the wheel progressively onto its hub.

Surely there is a difference between torqueing up a bolt (or nut) when fitting and the routine torqueing before each outing. When fitting it is important to get the torque correct, within tolerances.

 

As an ongoing practice the check is there to identify and rectify any that are beginning to come loose. If the "static friction" is "greater than the torque required" it can only mean that the bolt has not moved and is therefore not becoming loose. Therefor, the big issue is not "one or two clicks" but whether there is movement before the first click. If a bolt or nut is regularly becoming loose there must be an underlying problem which should be investigated.

[Fireman Iain]

Stevan, I could be wrong, but technically I stand by my first post. My Swift has, IIRC a wheel nut torque of 110Nm. If I apply 110Nm to a static nut and it doesn't move, all I know is that it takes a minimum of 110Nm before the nut begins to tighten down. Which is not the same as a nut being tightened to 110Nm.

 

In theory, I could apply a locking compound and tighten to, say 55Nm. When the compound sets, applying a torque of 110Nm will not turn the nut. The static friction outweighs the applied torque. But it's never been tightened beyond half of its required torque.

 

Practically, if I know a nut and its thread are not corroded, is clean, (lubricated or dry, depending on spec) and does not, for example, have thread lock applied, then yes, a quick check with a torque wrench set at 110Nm is probably adequate. But it's not the same as tightening the nut to 110Nm. The only way to do that is to apply said torque to a rotating nut, or bolt. Again, dry or correctly lubricted, as specified.

 

To boltonbob, the OP, I apologise, I'm getting carried away with pedantry.

[David P]

Surely there is a difference between torqueing up a bolt (or nut) when fitting and the routine torqueing before each outing. When fitting it is important to get the torque correct, within tolerances.

 

As an ongoing practice the check is there to identify and rectify any that are beginning to come loose. If the "static friction" is "greater than the torque required" it can only mean that the bolt has not moved and is therefore not becoming loose. Therefor, the big issue is not "one or two clicks" but whether there is movement before the first click. If a bolt or nut is regularly becoming loose there must be an underlying problem which should be investigated.

Hi Stevan. I have been at it for 44 years (engineering) and as I see it (like you) No movement and one click, does it for me, if there is movement there's something wrong.

[Coriolis]

To clarify your understanding, A bolt screws into a threaded hole in a surface. A stub protrudes from a surface with a thread upon it. A Nut can then be threaded onto said stud or bolt! You do the QA bit and leave the work to us Aircraft Engineers (retired) LOL

Quite so David. ...I'm pleased we agree on the mechanics

 

My point is that our friend in the video spoke exclusively of studs. ...then proceeded to tighten BOLTS. ..heads clearly visible with no sign of protruding studs with nuts

 

I haven't quite retired yet but happy to confirm my licence remains valid until 2020 (don't anticipate renewing again then)... but I don't think the hardware definitions changed from BCAR/AGS days despite the best (?) efforts of our EASA friends.

 

Don't know when you retired but note the use of the term Engineer as previously emblazoned on our old licences disappeared around 2005, when our Frence and German cousins decided the E word could only be awarded to those with degrees, rather than the likes us us who worked our way up via rainsoaked ramps.

 

Enjoy retirement, my friend, you're well shot of what they've done to our industry

 

C (once LAE 16564), now something unmemorable with B1. 1, 1. 2, 1. 3, 1. 4 & C. ... 47 years and counting (down).

Edited February 11, 2017 by Coriolis

[David P]

Stevan, I could be wrong, but technically I stand by my first post. My Swift has, IIRC a wheel nut torque of 110Nm. If I apply 110Nm to a static nut and it doesn't move, all I know is that it takes a minimum of 110Nm before the nut begins to tighten down. Which is not the same as a nut being tightened to 110Nm.

 

In theory, I could apply a locking compound and tighten to, say 55Nm. When the compound sets, applying a torque of 110Nm will not turn the nut. The static friction outweighs the applied torque. But it's never been tightened beyond half of its required torque.

 

Practically, if I know a nut and its thread are not corroded, is clean, (lubricated or dry, depending on spec) and does not, for example, have thread lock applied, then yes, a quick check with a torque wrench set at 110Nm is probably adequate. But it's not the same as tightening the nut to 110Nm. The only way to do that is to apply said torque to a rotating nut, or bolt. Again, dry or correctly lubricted, as specified.

 

To boltonbob, the OP, I apologise, I'm getting carried away with pedantry.

You are correct, but who in their right mind would put thread lock onto wheel nuts? Not something I would or have done ever!

Quite so David. ...I'm pleased we agree on the mechanics

 

My point is that our friend in the video spoke exclusively of studs. ...then proceeded to tighten BOLTS. ..heads clearly visible with no sign of protruding studs with nuts

 

I haven't quite retired yet but happy to confirm my licence remains valid until 2020 (don't anticipate renewing again then)... but I don't think the hardware definitions changed from BCAR/AGS days despite the best (?) efforts of our EASA friends.

 

Don't know when you retired but note the use of the term Engineer as previously emblazoned on our old licences disappeared around 2005, when our Frence and German cousins decided the E word could only be awarded to those with degrees, rather than the likes us us who worked our way up via rainsoaked ramps.

 

Enjoy retirement, my friend, you're well shot of what they've done to our industry

 

C (once LAE 16564), now something unmemorable with B1. 1, 1. 2, 1. 3, 1. 4 & C. ... 47 years and counting (down).

I did build a trailer that had studs & nuts and not bolts to attach the wheel?

[Coriolis]

The only things of note I ever built were a recumbent bicycle, a 28ft sailing boat and a couple of garden sheds. ..none of those had studs and nuts. ..

 

But more to the point, neither did the caravan hub being tightened in the video

 

That's the main problem when one moves from earning an honest living to auditing what others are doing. ...teaches one to see what's actually there rather than assume

 

Shame you retired, I'm sure you'd have done really well in QA. ...or rather Compliance Monitoring as the heathens on the continent have insisted we're to be called now. ....whose language was it they decided to use? Oh yes, English. ...and we seem to be communicating wonderfully, even if we have rather strayed off topic

 

I'll get my coat. ...

[Stevan]

 

Practically, if I know a nut and its thread are not corroded, is clean, (lubricated or dry, depending on spec) and does not, for example, have thread lock applied, then yes, a quick check with a torque wrench set at 110Nm is probably adequate. But it's not the same as tightening the nut to 110Nm. The only way to do that is to apply said torque to a rotating nut, or bolt. Again, dry or correctly lubricted, as specified.

 

 

This is my point, if a wheel bolt (or nut) is correctly torqued last time it was fitted, subsequent checks need only be that it has not moved, one click is enough. To check that it is properly torqued requires that it be loosed off, checked that it is still clean and dry/lubricated and then be re-torqued, and nobody seems to be suggesting that!

[Ern]

To clarify your understanding, A bolt screws into a threaded hole in a surface. A stub protrudes from a surface with a thread upon it. A Nut can then be threaded onto said stud or bolt! You do the QA bit and leave the work to us Aircraft Engineers (retired) LOL

Agh! But at what point does a bolt become a screw? A bolt typically has a portion of plain shank from which a thread is reduced by cutting or rolling. The length of thread is determined by a ratio of the diameter from the sharp end. Where as a screw had no plain shank and a thread near enough all the way up to the head? Perhaps the right name for the wheel fastener is "screw"?

[David P]

Agh! But at what point does a bolt become a screw? A bolt typically has a portion of plain shank from which a thread is reduced by cutting or rolling. The length of thread is determined by a ratio of the diameter from the sharp end. Where as a screw had no plain shank and a thread near enough all the way up to the head? Perhaps the right name for the wheel fastener is "screw"?

Not necessarily so. You can get all threaded bolt which are threaded to the underside of the head. You can also get bolts that have unthreaded shanks. Ok I should have said threaded and not screwed, but a bolt does not have a sharp end, but in my defence I was trying to make it simples. LOL

[Ern]

Not necessarily so. You can get all threaded bolt which are threaded to the underside of the head. You can also get bolts that have unthreaded shanks. Ok I should have said threaded and not screwed, but a bolt does not have a sharp end, but in my defence I was trying to make it simples. LOL

You should know better than to try to make it simple on this forum. Terms used vary from industry to industry, but the fastener industry which serves all industries, call a fastener with a thread near enough up to the head a screw. The "sharp end" is my slang. It's the opposite end to the blunt end.

[CommanderDave]

Stevan, I could be wrong, but technically I stand by my first post. My Swift has, IIRC a wheel nut torque of 110Nm. If I apply 110Nm to a static nut and it doesn't move, all I know is that it takes a minimum of 110Nm before the nut begins to tighten down. Which is not the same as a nut being tightened to 110Nm.

In theory, I could apply a locking compound and tighten to, say 55Nm. When the compound sets, applying a torque of 110Nm will not turn the nut. The static friction outweighs the applied torque. But it's never been tightened beyond half of its required torque.

Practically, if I know a nut and its thread are not corroded, is clean, (lubricated or dry, depending on spec) and does not, for example, have thread lock applied, then yes, a quick check with a torque wrench set at 110Nm is probably adequate. But it's not the same as tightening the nut to 110Nm. The only way to do that is to apply said torque to a rotating nut, or bolt. Again, dry or correctly lubricted, as specified.

To boltonbob, the OP, I apologise, I'm getting carried away with pedantry.

 

 

When you check a nut is correct with a torque wrench you should undo it a half turn then torque to the correct measurement . This is to ensure the nut is not seized .

 

 

Dave

[Chillout]

Having just quickly browsed through this topic there appears to be something missing regarding torque settings. Has your torque wrench been calibrated i. e. the settings on the torque wrench are correct. Having been in engineering for years all measuring devices should be calibrated at regular intervals, subject to their use and manufacturers instructions. The same goes for torque settings, caravan wheel studs/nuts. If you follow manufacturers instructions you shouldn't go far wrong with the right calibrated tools.

[Coriolis]

You should know better than to try to make it simple on this forum. Terms used vary from industry to industry, but the fastener industry which serves all industries, call a fastener with a thread near enough up to the head a screw. The "sharp end" is my slang. It's the opposite end to the blunt end.

Aaaah well now, if we're really going for it. ..woodscrews often don't have threads all the way to the head (are they still called threads in a non-parallel fastener?), yet we still call them screws. ...

 

Not that I'm recommending them to hold on caravan wheels, but. ..

 

Sorry, took my coat but came back for the (tin) hat and couldn't resist

 

We ought to take this conversation to the bar. ...

Edited February 12, 2017 by Coriolis

[Orionwelwyn]

We have tell tales (millenco) fitted on our Pegasus to which then reqs just a glance before each trip to see whether any of the bolts have moved

If its ok for hgvs its ok for me

Edited February 12, 2017 by Orionwelwyn

[canal craft]

When you check a nut is correct with a torque wrench you should undo it a half turn then torque to the correct measurement . This is to ensure the nut is not seized .

 

 

Dave

Dave is correct, as this is the only way you can actually measure any fixing torque, be it a wheel nut / stud or cylinder head bolt etc, and it reduces thread binding. .

 

It this instance, with a wheel fixing, by slackening the fixing a quarter to half turn, you know the fixing isn't seized and you should be able to undo it if you get a puncture. By then re-torquing it, you will achieve the click or click-click as the correct torque and clamping force is attained.

 

If you just set the torque wrench and try the nuts etc and it goes click, all you have achieved is a simple hearing test!

 

In my 40 plus years as a workshop technician / Service Manager, I have used a variety of torque wrench's, some give one click, others two. Every year the torque wrenches were sent for calibration testing and re-calibrated.

 

After use, always fully unwind the torque wrench to remove the tension from the spring, leaving any tension weakens the spring, and it will read low.

[daveat92]

We have tell tales (millenco) fitted on our Pegasus to which then reqs just a glance before each trip to see whether any of the bolts have moved

If its ok for hgvs its ok for me

 

Same here, quick glance and carry on if they are all still lined up correctly.