Never using an adjustable torque wrench again!

[Brucey]

There's a thread somewhere about not using a torque wrench at all and going just by feel. If anyone can find it I would be very grateful!

Good mechanics are often as good without a torque wrench as poor mechanics are with one. The problem is that good mechanics only got that way by breaking stuff often enough that they learned how not to do it. Learning 'feel' is certainly not something you can do by reading about it.....

cheers

[Vorpal]

Checking a torque wrench isn't hard.

It needs to be on a bolt or something fixed (to withstand torque) and set parallel to the ground. Then hang a known weight off it at a measured distance, and the torque is weight X distance. The torque wrench, set to that should click when the weight is applied. If it doesn't they have an adjustment screw. You have to take the weight off to adjust it, and it has to have the correct lubrication.

I expect that t'interweb or YouTube have instructions, if my description is not enough.

p.s. when I was working as a machinist, I only used a torque wrench on lug bolts. I don't do it so often these days, and trust a torque wrench better than my feel

[pete75]

There's a thread somewhere about not using a torque wrench at all and going just by feel. If anyone can find it I would be very grateful!

Good mechanics are often as good without a torque wrench as poor mechanics are with one. The problem is that good mechanics only got that way by breaking stuff often enough that they learned how not to do it. Learning 'feel' is certainly not something you can do by reading about it.....

cheers

Good luck to anyone without a torque wrench and torque angle gauge working on torque to yield stuff.
I wouldn't call someone who learns by breaking stuff good - experienced maybe but good no.

[Vorpal]

There's a thread somewhere about not using a torque wrench at all and going just by feel. If anyone can find it I would be very grateful!

Maybe this one? viewtopic.php?f=5&t=91860&p=837530

[rmurphy195]

I assume the torque spec' varies with how/if the thread has been lubed (dry, oil, grease, anti-seize etc..) is a c. 20% tolerance enough to cover this?

Torque is usually specified dry. A lubricated thread will show a lower torque than the "real" value, and so overtightening will occur. By a wide margin.

Having said this I've never had a problem with the oil drain plug on my cars - yet (these are always covered in oil, so maybe when the value is specified that is taken into account). Or maybe for certain bolts such as oil drain plug, car wheel bolts) it depends as much on the contact area between the bolt head and the surface of the sump/wheel.

[Manc33]

Not sure if this is worth using anymore, each crank hole:

Right:


Left:


I think I'll just go back to Octalink 2, or square taper

[Brucey]

I assume the torque spec' varies with how/if the thread has been lubed (dry, oil, grease, anti-seize etc..) is a c. 20% tolerance enough to cover this?

Torque is usually specified dry. A lubricated thread will show a lower torque than the "real" value, and so overtightening will occur. By a wide margin.

Torque can be specified wet, dry and/or with a specified surface treatment. Dry torque is generally specified for new bolts/fittings which have a controlled surface finish, and if so this is valid for the first tightening only. Most bicycle assemblies are specified 'wet' in that the fastening usually has grease or threadlock on it; you need to read the instructions to see what the condition is and/or examine similar new parts carefully; blithely assuming it is one particular way without checking is how things get screwed up.

IIRC the crank arm pinch bolts in HTII have grease under the heads and pre-applied threadlock on the screw threads. Most types of threadlock have a lubricating effect, such that the torque is effectively a 'wet' one.

cheers

[Brucey]

Not sure if this is worth using anymore....

they do look pretty jiggered. They look as if the bolts have been fitted/assembled dry, the crank spline interface (which would never have been tight enough as a consequence) has moved and has worn, and then the bolts have been tightened again. I think the distinctive gouges seen are made if the crank spline is worn and the crank is then 'too pinched' when the bolts are tight. This causes the bolts to see cycling bending as they are tightened, much as I described earlier, and this is why they break.

cheers

[NATURAL ANKLING]

Hi,
Head bolts only!
The problem with torque wrenches are that unless it says oil threads or you use new dry parts then you will always be £$&&ing in the dark...........................

[Manc33]

I used an online calculator and 12Nm is almost exactly 4KG (8.85 lbs) of pressure on a 1ft bar.

https://www.convertunits.com/from/N+m/to/ft+lb

I'm no good at working out this stuff but I assume that's going to be 8KG on a 6 inch bar?

The 5mm (Wera) allen key I'll be using is exactly 6 inches, so I can probably guess at that.

If not, I better get stocked up on bags of sugar.

It is actually quite a lot of pressure. If these threads and the underside of the bolt head is all greased, 12Nm is tighter?

But Shimano says 12Nm and they grease them.

[iandusud]

When I bought my carbon fibre road bike I adjusted the seat and then went out for a 70 miler. I stupidly didn't take a multitool with me and about half way round realised that my seat post was slipping down. I finished the ride with the seat about 4cm lower than is should have been and was thankful that I didn't end up with my left knee flaring up, as it's rather sensitive to low seat height. However, the reason behind this was that I was obviously being a bit over cautious when tightening the pinch bolt, being aware that CF is a bit more sensitive that alloy. I did't have a suitable torque to measure 5nm but with a suitable weight (in this case a 4kg kettle weight that my son uses), a piece of nylon cord to suspend it, a long allen key and a tape measure, I was able to accurately tighten the pinch bolt to the specified torque. I then went out and bought a cheap beam wrench, which I trust much more than the more expensive clicky ones, and tested it against my homemade affair. The beam wrench was spot on I'm pleased to say. However this is the first time in over 45 years of regular spannering on bikes I have ever used a torque wrench. Whilst I don't disapprove of their usage in certain circumstances I don't think there is any substitute for developing a good feel when using spanners with a sympathy for the materials being used. I have also worked extensively on motorcycles and cars and I only got a torque wrench when I got a diesel engined car, for torquing down the cylinder head. I have always done all other cylinder heads by feel, the important thing being to tighten them down evenly and not go at them like a gorilla!

[Brucey]

dangling weights etc is a pretty good way of checking the calibration of a clicky torque wrench, but having a beam wrench to hand is even better of course.

If you torque stuff on a daily basis then a clicky wrench is just easier to use on most jobs. There are a few (just a few, mostly on cars) jobs that require either a clicky wrench only or a beam wrench only, so you end up with both types anyway if you do a lot of this sort of thing. However if you don't torque stuff often, then I think a clicky wrench is just a waste of time; it ought to be checked pretty much every time it is used (if it has sat for months between uses) and the checking takes longer than it would to use a beam wrench to do the job.... so I would suggest that a beam wrench would be a better tool if you only have one torque wrench and only use it infrequently.

BTW I would (for most practical purposes) lump electronic torque wrenches in with clicky wrenches. Yes they are different (when they are working right they are liable to be more accurate than clicky wrenches at low torque values); they are not susceptible to the same faults as clicky wrenches, they have their own faults..... but the net outcome is essentially the same; if you only need the thing occasionally then it may (for all kinds of reasons) not give accurate readings when you pull it out of the box and go to use it. For the occasional user they are an expensive way of potentially making even more trouble for yourself.

cheers

[Manc33]

It was an expensive way of making even more trouble in my case.

I read somewhere when a torque wrench is measuring at 50Nm or figures higher than any parts on a bike, they are accurate, but no one can make a clicky one that's accurate at torques like 6Nm and so on.

At some point I think I will get one of those Ritchey ones (it's set at one torque, with a dial to swap between something like 4Nm, 5Nm and 6Nm only) for doing stem bolts and chainring bolts. It is important IMO to have those with the bolts at an even pressure.

When it comes to cassette lockrings and seatposts, I think tightening them a lot you end up knowing what's the right amount by hand. Even on a stem I guess you can get it close but it will never be exact, hence the Ritchey thing sounds useful.

[horizon]

There's a thread somewhere about not using a torque wrench at all and going just by feel. If anyone can find it I would be very grateful!

Maybe this one? viewtopic.php?f=5&t=91860&p=837530

Thanks for that Vorpal!

NB I think it's a thread well worth reading. I've resurrected it now.

[Brucey]

At some point I think I will get one of those Ritchey ones (it's set at one torque, with a dial to swap between something like 4Nm, 5Nm and 6Nm only) for doing stem bolts and chainring bolts. It is important IMO to have those with the bolts at an even pressure...

The biggest errors usually come at lower torque values in adjustable clicky wrenches, it is true. But any clicky wrench is susceptible to the same issues, even if it is adjustable over a small range only or indeed even if it is a fixed value device. I have some fixed value clicky wrenches (for particular jobs) and they are brilliant if you are doing lots of repeat work, (there is zero chance of picking up a tool that fits the fastener and is set wrongly, if you get your ducks lined up in a row) but for occasional use they still have problems. If you use those tools all the time then the clicky mechanism wears and/or can otherwise go out of calibration.

I would still advocate that fixed value clicky wrenches are checked regularly and that occasional users should not assume that they are going to perform as intended if they have lain unused for weeks or months beforehand.

cheers