121–130 of 150 posts
This is a bad name. The word "smart" implies the bolt can connect to my phone via bluetooth and I can download an app that will tell me the status of the bolt.
If you think the head of a bolt with an indentation in it is going to stay clean, especially one that has to stay tight, then you have not held a wrench often enough, my friend. Once that red spot gets dirty, you're not going to be able to tell if it's brick red because it's loose, or brick red because it has dirt on it. It's probably going to take you longer to clean the bolt than to get the torque wrench on it.
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Even where you can't measure the stretch directly, torque-plus-angle is a better way to achieve consistent stretch than torque alone.
In case anyone else needs to look this up, torque-plus-angle means seating the threaded fastener to a base torque, and achieving the target tension from there by further turning the fastener a specified angle. So super duper simple and something that many of us have done instinctively or from instructions, now we know there is a term for this general technique. Cf https://dannysengineportal.com/torque-specification-t…
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I can guarantee a roller coaster track at any modern amusement park in America is inspected far more frequently and is much safer to travel on than the interstate highways and bridges that get you to the parking lot.
Would you say more on this? Curious
vs.
I worked at an amusement park during summers in highschool and coaster track maintenance was serious business. The entire tracks were walked and inspected end to end twice a day (at open and at close). There was a meticulous paper trail of any and all maintenance, measurements, conditions, etc. Their insurers demanded a high standard because ultimately it would have cost the park millions and millions of dollars in liabilities if there were accidents.
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That’s true, but you can have a qualified inspector mark bolts with goo with a paint line that straddles to the fastening surface. Then you can just inspect the paint line for movement, which gets you most of the same functionality at significantly lower cost. Of course, that requires a trustworthy inspector, which is one application where smartbolts become useful, if you don’t have a trustworthy inspector available…
That line is fine if the bolt winding itself loose is your only failure scenario, but some might have others as well. What of they clamp a part that can subtly deform in certain exceptional situations? Then you could have a bolt with zero tension that is still perfectly aligned with the marker line from when it was properly torqued. What I find somewhat surprising is that they make the "ok" indication black. The cry…
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That’s true, but you can have a qualified inspector mark bolts with goo with a paint line that straddles to the fastening surface. Then you can just inspect the paint line for movement, which gets you most of the same functionality at significantly lower cost. Of course, that requires a trustworthy inspector, which is one application where smartbolts become useful, if you don’t have a trustworthy inspector available…
Totally agree. And two cents to add. The so called smart bolt adds movable parts in side a part supposed to be inertia and at the same time might compromise the strength in comparison with ones with the same profile and body material. And when faulty, it actually more dangerous than ordinary ones: now your torque wrench and the bolt gives different readings, which one to trust?
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I’m not getting your point here, won’t there always be inherent trade offs? If you scale the specified torque, you risk over-tensioning. If you scale the dimensions of the fastener, that has lots of consequences. Is there some safety factor here you can add “for free” that I’m not seeing? Otherwise, why is it that you “generally” pre-empt this caveat with safety factor versus coming up with a more reliable way to ach…
The general idea is that proper bolt installation is a solved problem…at least in so far as ordinary industrial/commercial/construction applications are concerned. There’s an informed experienced trade base, a well established supply chain, and sound engineering practices already. To put it another way, the right tension includes a safety factor. And engineering practice specifies testing and inspection and proven ma…
Basically, it is a "solved problem" by designing things stronger than they have to be, and spending more on testing and inspection than necessary.
I'm sure the cases where these things are economical are fairly few, at least today, but if everyone took your attitude no progress would happen at all.
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Would you say more on this? Curious
https://infrastructurereportcard.org/ vs. I worked at an amusement park during summers in highschool and coaster track maintenance was serious business. The entire tracks were walked and inspected end to end twice a day (at open and at close). There was a meticulous paper trail of any and all maintenance, measurements, conditions, etc. Their insurers demanded a high standard because ultimately it would have cost the…
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A problem with many torque wrenches is that they click (or beep) when the set torque is reached, but they do not prevent tightening beyond that, nor do they have any way to indicate how much overtightened the fastener might be. It seems to me that these bolts have the same issue. Ever wonder why the tire shop has tightened your wheel lug nuts so tight that you can't get them off with the hand wrench when you need to…
That explains a lot. Had a tire shop tighten the bolts on my old car so extremely tight that the threading on the bolts were broken. Every time I changed the tires after that I had to use a wrench with a looong bar attached to loosen the bolts (In Norwegian we call this a “latmannsarm which directly translates to lazy man arm, not sure what the English word would be). No matter how much grease or how much care I took…