Drago
Legendary Member
- Location
- Suburban Poshshire
One of the of the biggest common factors among convicted criminals is a lack of torque wrench ownership.
Torque wrench, how critical
- Thread starter Soltydog
- Start date
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Jimmy Doug
If you know what's good for you ...
I was going to start a thread on this, so I'll hop on this one. After years of deciding which side of the line I fall on, I've eventually come to the conclusion that it is safer to use torque wrenches these days. Sure, in the past it probably wasn't all that critical. But now, things are engineered to a higher and higher precision, and so the tolerances are becoming lower. I found an interesting article here. Of particular interest to me in this article is this part:
"At Interbike [2008], we had a transducer set-up to a 0.25in breaker bar and hex bit socket, and we asked for volunteers to tighten the bolts at the stem/steerer to the recommended torque value [4.5Nm – a common spec for those types of parts]," said marketing product manager Glenn Kalnins. "Of the nine volunteers, only one person was within spec (+/- four percent) of the 4.5Nm value [and] some people pulled five and six times the value that was set on our clicker.
"Imagine your stem faceplate needs to be tightened to 5Nm to hold your brand new carbon bar in place and you or your local mechanic tightens it to 25Nm or 30Nm. This variability is totally unacceptable in terms of safety and liability in the bicycle industry."
Given that quoted safety factors in some high-end parts can be as low as 1.1 (meaning that exceeding the spec by just 10 percent can result in failure), it doesn't take much of a ham-fisted mechanic to do some real damage. Conversely, the narrow window also means it's easy to leave a bolt too loose, resulting in unwanted movement or slip.
So, I shall be ordering a torque wrench just as soon as I can persuade my wife that I need one! Trouble is, though, and this is often not known, one torque wrench probably isn't enough: one is needed for low torques, and another is needed for high torques.
"At Interbike [2008], we had a transducer set-up to a 0.25in breaker bar and hex bit socket, and we asked for volunteers to tighten the bolts at the stem/steerer to the recommended torque value [4.5Nm – a common spec for those types of parts]," said marketing product manager Glenn Kalnins. "Of the nine volunteers, only one person was within spec (+/- four percent) of the 4.5Nm value [and] some people pulled five and six times the value that was set on our clicker.
"Imagine your stem faceplate needs to be tightened to 5Nm to hold your brand new carbon bar in place and you or your local mechanic tightens it to 25Nm or 30Nm. This variability is totally unacceptable in terms of safety and liability in the bicycle industry."
Given that quoted safety factors in some high-end parts can be as low as 1.1 (meaning that exceeding the spec by just 10 percent can result in failure), it doesn't take much of a ham-fisted mechanic to do some real damage. Conversely, the narrow window also means it's easy to leave a bolt too loose, resulting in unwanted movement or slip.
So, I shall be ordering a torque wrench just as soon as I can persuade my wife that I need one! Trouble is, though, and this is often not known, one torque wrench probably isn't enough: one is needed for low torques, and another is needed for high torques.
black'n'yellow
Guest
Sorry, after reading that I've stopped taking this thread seriously...
"What's this - no torque wrench, son..? You're nicked.."
What about one for medium torques..?
B&Y, so you obviously did not read the post by Jimmy Doug. Quality control is what I am talking about.
For you who are sitting on the fence on this subject here is a good read.
http://www.cyclingnews.com/features/torque-wrenches-why-you-need-one-and-how-to-use-them
Now perhaps B&Y or the post collector Adrian might like to point us to a write up that says they do not need to be used
For you who are sitting on the fence on this subject here is a good read.
http://www.cyclingnews.com/features/torque-wrenches-why-you-need-one-and-how-to-use-them
Now perhaps B&Y or the post collector Adrian might like to point us to a write up that says they do not need to be used
black'n'yellow
Guest
Not sure what you mean by QC in this instance. If a fastening is tightened sufficiently to the point where it neither damages the part it is securing nor destroys the thread which is holding it, then that is all that is needed. There's your QC, right there.
Anyway, look -- I understand what torque wrenches do - and why people might need them. I've read that article before and I'm sure it's very useful if you are not confident with your own abilities. Incidentally, the pic of Munoz shows him using the wrench incorrectly, but I'm sure you don't need me to tell you that
Anyway, look -- I understand what torque wrenches do - and why people might need them. I've read that article before and I'm sure it's very useful if you are not confident with your own abilities. Incidentally, the pic of Munoz shows him using the wrench incorrectly, but I'm sure you don't need me to tell you that
black'n'yellow
Guest
no need, thanks.
If it was posed, then there is even less excuse. Not sure of the particular model of wrench he is using, but I can't see how holding it by the neck would activate the clicker - although his particular wrench may work differently.
Anyway, we seem to be going round in circles here and I don't really have anything else to add. So if you don't mind I will step off the merry-go-round now...
No problem holding a click torque wrench by the neck if you are only doing a low torque setting.
No problem with you jumping off, perhaps somebody else would like to talk up the benefits of not using a torque wrench as apart from a bit of cost I can see no reason not to use one.
No problem with you jumping off, perhaps somebody else would like to talk up the benefits of not using a torque wrench as apart from a bit of cost I can see no reason not to use one.
