Recommendations for a cheap torque wrench

Ive got these and they are spot on as can be I suppose.

 
enuff_zed said:
I think there may be a slight misunderstanding there?
Once the torque wrench has clicked, you can carry on turning it as much as you like but every tiny movement will increase the torque applied. The wrench, once clicked, just becomes a bar.
What I was taught was that you should go slow and steady until it clicks. This is then the correct torque. I agree with you that whizzing the thing around as fast as you can will lead to the wrench clicking too early, as it effectively gets a sudden loading on it.
For the crushable washer scenario, I guess this is why my teaching included going back to every fastener a second time and checking it again. Something I still do, and yes, on occasion I get another slight tweak before it clicks.
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Well..the interesting thing is .. (I treated myself to two electronic version 1/2" and 3/8",..but that's not the interesting part)..using the electronic versions they 'beep' as they get close to the requested torque limit..at the torque limit they emit a constant tone..when I was winding up my caliper cradle bolts to 120nm as I approached the limit it beeped..at the limit the tone..but..holding it there..it went back to beep..the fastener had move very fractionally and the torque reduced..I had to re-apply torque and it took a couple of very minor iterations until the torque was steady..you'd never notice that with the 'clunk' approach!
 
I picked one up years ago from the middle isle of Lidl. Seems good a was very reasonable from memory.
Must remember to keep winding it back down!
 
MikeyH said:
I’m not not sure on the size, might be 1/2”, I will check in the morning, as for the size it is to do my lower wish bone at first and it looks a bit cramped so might be best to have a smaller one. Thank you all for your help, as always, brilliant. :thumbsup:
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If It's for your wishbones then I've got all the gear we'll need so don't panic.
 
smorris_12 said:
It's something I heard along the way which made sense so it stuck with me. The fastener is only properly tight when it stops moving with the correct torque applied; the torque wrench tells you that you're applying the correct torque, not that the fastener has finished overcoming whatever friction/stiction/other[1] there is that allows it to keep creeping round. You're not increasing the force but maintaining it. I suppose a good example would be some form of deformable sealing ring (maybe a copper washer would be a good example.) It gets squeezed at whatever force is applied by, say, 50Nm but it takes a finite time for it to finish its non-elastic deformation and crush properly. Apply the 50Nm and immediately take it away again and it's not tightened down properly.

That's how I understand it anyway. It always amuses me to see tyre places wave torque wrenches at wheels going as fast as they can. Say the bolt is 90% tight they don't give it anywhere near enough time to overcome stiction and start moving before they're off to the next.


[1] I am not a tribologist
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We could have a 'field day' about physics/ engineering '101' with this topic. I find it all extremely interesting but doubt most do.
Torque is a measurement of force over distance. In the instance of tightening helical thread fasteners, the distance in real terms is the amount of 'stretch' the thread realises divided by the force.
The whole point of 'torqueing' a helical thread is to not stretch the thread further than it was designed to 'spring back' upon release. If you overtighten a thread it permanently deforms and cannot return to it's original state, so is compromised.........I'm gonna stop now as it gets a bit boring TBH! ;)
 
Pondrew said:
We could have a 'field day' about physics/ engineering '101' with this topic. I find it all extremely interesting but doubt most do.
Torque is a measurement of force over distance. In the instance of tightening helical thread fasteners, the distance in real terms is the amount of 'stretch' the thread realises divided by the force.
The whole point of 'torqueing' a helical thread is to not stretch the thread further than it was designed to 'spring back' upon release. If you overtighten a thread it permanently deforms and cannot return to it's original state, so is compromised.........I'm gonna stop now as it gets a bit boring TBH! ;)
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Well googled 🤣
 
What it boils down to is that 99% of diy car maintainers read all about torque settings, rush out and buy a torque wrench, research the correct torque value for every nut and bolt, then don’t do it correctly but feel in their own mind that they have done it all ‘by the book’. So many variables involved, I’m willing to bet they are no more accurate than someone with experience doing it by feel.
 
enuff_zed said:
What it boils down to is that 99% of diy car maintainers read all about torque settings, rush out and buy a torque wrench, research the correct torque value for every nut and bolt, then don’t do it correctly but feel in their own mind that they have done it all ‘by the book’. So many variables involved, I’m willing to bet they are no more accurate than someone with experience doing it by feel.
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Absolutely agree. But the old 'placebo effect' makes us numpties sleep at night! :)
 
Pondrew said:
We could have a 'field day' about physics/ engineering '101' with this topic. I find it all extremely interesting but doubt most do.
Torque is a measurement of force over distance. In the instance of tightening helical thread fasteners, the distance in real terms is the amount of 'stretch' the thread realises divided by the force.
The whole point of 'torqueing' a helical thread is to not stretch the thread further than it was designed to 'spring back' upon release. If you overtighten a thread it permanently deforms and cannot return to it's original state, so is compromised.........I'm gonna stop now as it gets a bit boring TBH! ;)
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Very interesting, you’re not related to James May b any chance.
 
enuff_zed said:
What it boils down to is that 99% of diy car maintainers read all about torque settings, rush out and buy a torque wrench, research the correct torque value for every nut and bolt, then don’t do it correctly but feel in their own mind that they have done it all ‘by the book’. So many variables involved, I’m willing to bet they are no more accurate than someone with experience doing it by feel.
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However there are gorillas out there that just hang off ever nut! So somewhere near the correct value is better than over tightening to death ☠️ 🤔
 
Reamesy said:
However there are gorillas out there that just hang off ever nut! So somewhere near the correct value is better than over tightening to death ☠️ 🤔
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I’m assuming my advice is being taken by sensible folk……. Such as your good self. 😎
 
Very difficult finding a cheaper torque wrench. As it will most likely only be used for the yearly oil change and rear wheel tightening after drain clearance I am loath to spend more than £50.00 on one. Needs to be between 25nm and 130nm but the £40.00 Draper on Amazon I was going to buy only goes down to 30nm. Is 5nm more too much and can’t I tighten without a torque wrench, I used to in the 70s without leaking?
 
MikeyH said:
Very difficult finding a cheaper torque wrench. As it will most likely only be used for the yearly oil change and rear wheel tightening after drain clearance I am loath to spend more than £50.00 on one. Needs to be between 25nm and 130nm but the £40.00 Draper on Amazon I was going to buy only goes down to 30nm. Is 5nm more too much and can’t I tighten without a torque wrench, I used to in the 70s without leaking?
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Definitely do not tighten the sump plug too much. In fact, it really only needs a tweak. It's more important that you fit a new copper washer every time.
What you could do is assemble a nut and bolt in a vice and practice doing it up to the minimum 30Nm. you'll soon get a feel for it. Then you should be able to judge a little bit less for the sump plug.
 
Iv'e been online looking and it seems that a 3/8" is the answer with a 1/2" adaptor, all mine are 1/2". Sorry, I know I'm going against the grain on here enuff_zed but I will be using an oil sucker down the dipstick hole so the drain plug wont be a problem. The wrench is really for the oil filter cover at 25nm. :thumbsup:
 
MikeyH said:
Iv'e been online looking and it seems that a 3/8" is the answer with a 1/2" adaptor, all mine are 1/2". Sorry, I know I'm going against the grain on here enuff_zed but I will be using an oil sucker down the dipstick hole so the drain plug wont be a problem. The wrench is really for the oil filter cover at 25nm. :thumbsup:
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Well, in that case, if you know it's on correctly now, just put a paint mark or something on the edge of the cap and the housing, then do it back up to that. Tbh, the caps tend to bottom out when they get to fully tightened anyway. Turn easily then just stop.
 
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