Tool porn

As a new comer to soot bikes, and the bike was fitted with a qr seat clamp. So I replaced that with a standard seat clamp, and the got carbon bars so wanted to be safe.

For steel/Ali bikes I would not bother.

Feel like I started this, I was just wondering about @Jurek wrenches as jurek is very competent(is that right) in storing and looking after his tools. So value his consciencesness of tool storage.

I agree with you on this Kimmo.
Although we were all inexperienced at some point and a torque wrench is a good idea when learning the 'feel' isn't it. And it takes a few stripped bolts and accidents to really learn too.
I've never used a torque wrench on a bike to be honest, but I'm not a professional bike mechanic and tend to under-torque. I would definitely get the torque wrench out if I had a carbon bike!
But a torque wrench is really needed when it comes to liability, handover to customers and a good way for employees to check themselves during assembly.
We made a big stainless kitchen recently with custom handles - one of our handles came loose 4 weeks later and it took a 7h round trip to do that warranty job (it involved removing a big fridge door) just to re-torque a handle - It could have been me, an employee or the contractor who fitted the kitchen who under-tightened.... I'll be specifying a torque to everyone involved going forward.

I use thread lock on things like that

yeah, thread lock is ideal for that application and we probably should have done that on big heavy fridge doors to be honest :)
Although we fit alot of handles and they don't tend to budge when tightened right.

I tend to use thread lock on all my furniture connections for piece of mind. That said the cafe / shop type customers are terrible at reporting anything so no idea if it works or not. No news is good news.

I go back to a job recently and someone had replaced sapele veneer stool tops with some random Far Eastern ply that looked like it had been but with a butter knife 🤦‍♂️

Yeah, it's a good shout.
Ideally we'd use those fixings with thread lock already on the ends, for the sake of a few pence.

tool can't account for the degree of friction on the fastener

Isn't this EXACTLY what torque wrenches are for?

Is see the wera Xmas calendar has been announced. Not sure I need branded salt and pepper shakers

Some folks boggle the mind.

You wonder how some of these jokers can even move around without bumping into things.

I really don’t understand how some people get through life.

There’s a lots of people come to the track multiple times a week and yet, every day I see at least one of these experienced track riders try and turn the pedals of a track bike around with the rear wheel on the deck and they look like they don’t understand what’s happening. Every. Single. Day.

Another favourite is the wheel nut removers. Changing wheels, wheel nuts completely off. Changing sprocket, wheel nuts completely off. Tensioning chain, wheel nuts completely off. WHAT THE FUCK ARE YOU DOING?!

I sometimes ride with someone that turns their ’fixie’ upside down spins the cranks as hard as they can and then uses a micro fibre cloth to clean the chain. Wtf.

Isn't this EXACTLY what torque wrenches are for?

No.

The torque wrench is supposed to account for a particular degree of stretch of the fastener, through an assumed amount of friction which is always subject to variation, and which an experienced hand can largely differentiate from the tension.

The torque wrench can't tell the difference between tension and friction, and the flex built into the wrench somewhat interferes with the effort to sense that if the user bothers to try.

Come to think of it, sensing the difference is probably mostly based on experience, beyond noticing any roughness in the friction... Or maybe the friction has a more linear quality, I'm not sure. My muscles know the difference; sometimes the intellect adds a fudge factor due to this or that.

No

Maybe an example can illustrate it; consider tightening a guitar string - we're interested in the tension of the string, but if we try to achieve a particular tension only based on a threshold of force required to turn the tuning knob, we have to guess how much friction we're also fighting along with the increasing tension - this is the friction which keeps the knob where we put it.

Instead, if we pay close attention to how tuning knobs on various guitars feel every time we use them, along with other clues such as whether the worm gear is brass or steel, coarse or fine, greased or crunchy - after a few years we get pretty good at arriving in the neighbourhood of where we want it before we even pluck the string to check.

We're judging the particular amount of friction in each instance (as well as the tension) rather than using a blanket assumption. On the other hand, we also have to use our own fuzzy and fallible judgement to do that, rather than a repeatable mechanism. But experienced intuition is amazing stuff.

No

Well, at least we agree on that🙂

Nearly everybody who is doing important work with threaded fasteners uses a torque wrench, based on known tribological conditions to convert the desired tension into a torque to be applied. The only exceptions are the people doing more direct tension measurement by observing strain. Nobody who knows anything thinks that they can apply torque by feel more repeatably than even a cheap torque wrench.

What thread locks do you use?

important work

Care to define that?

I don't pretend I can apply torque more repeatably than a cheap torque wrench. But I'm damn sure I can guess the friction component of the required torque to achieve a given tension better than a one size fits all assumption.

Care to define that?

Aerospace, automotive, construction, pretty much any precision manufacturing.

I'm damn sure I can guess the friction component of the required torque

You really can't. Your calibrated hand is just guessing how much force you're applying, and like a torque wrench it can't diffentiate the components which make it up.

The old “self calibrating mechanic” routine.

Loctite 243

So 'important work' is a total red herring in this context (bikes, in case you forgot), which is far less uniform, critical, and high torque than that irrelevancy you cite.

My hand isn't calibrated. But my brain is paying attention to the shape of the curve on the graph, while the torque wrench only cares about it reaching a certain height.

Pull your head in. Noobs break shit with torque wrenches. I'm a qualified bike mechanic with decades of experience and I don't break shit.

If you don't use a torque wrench, what do you blame when you strip something? It's the equivalent of being able to blame the Saturday kid

So the only option for correctly torquing my bolts is to spend years as a bike mechanic?

far less uniform, critical, and high torque

M5 is M5, whether it's on a spaceship or a bicycle stem. Some stuff is lower torque than anything you routinely find on a bicycle, some obviously much higher. I still think something which will break my face if it fails counts as critical. At the high end of bicycle use, the window between not tight enough and too tight is as narrow as it is for anything out there.

No need to respond further, this is an internet forum not an exchange of letters. I'm not trying to persuade you, I'm just making sure people without your "qualifications and experience" have access to both sides of the argument so that they can make an informed decision for themselves.

I wonder how manufacturers actually determine if something is 2NM or 4NM toque.....
I really mean: I wonder is anything is tested in real life anymore, or if enough data is in the software/charts to avoid running any physical tests any more.....

avoid running any physical tests

No, standards compliance is still based on passing physical tests.

As far as threaded fasteners are concerned, the tension needed to avoid loosening is primarily determined by the thread size and material, as is the maximum before yield. That's why all your steel into aluminium M5 stem bolts are 4-6Nm regardless of who made them.

On a bicycle where hoop stress is what determines whether the clamped component slips or not, the max/min are quite well constrained by market forces, so manufacturers can design to those to avoid most issues even with mixed components.