[HN Gopher] Smartbolts ___________________________________________________________________ Smartbolts Author : tosh Score : 241 points Date : 2021-12-31 15:03 UTC (7 hours ago) (HTM) web link (www.smartbolts.com) (TXT) w3m dump (www.smartbolts.com) | RivieraKid wrote: | > Incredibly advanced. Surprisingly simple. | | > Unmatched Benefits | | > Unprecedented Value | | They think they are Apple, lol. | asimjalis wrote: | How do SmartBolts work? | JohnJamesRambo wrote: | I don't ride rollercoasters but if I did I would want them to use | these. | qbasic_forever wrote: | 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. | avianlyric wrote: | SmartBolts won't help if nobody looks at them. Unfortunately | most rollercoaster accidents are caused by humans simply | failing inspect structures, ignoring the results of inspections | or disabling safety systems. Rather than inspections being too | difficult to perform. | blamazon wrote: | I'm a mechanical engineer - smartbolts are cool but rarely used | in my experience. Much more commonly used are DTI washers: | https://en.m.wikipedia.org/wiki/Direct_tension_indicator | | Due to the washer style can be used with a wide range of | fasteners. The most common type, in my experience, due to the | ease of use, has a little bit of colored goo inside the arched | cells. The goo squirts out when the specified torque is reached. | | That being said, there are a lot of approaches to this same | problem. Another common technique is breakaway bolts that are | driven with a piece that snaps away when a certain torque is | reached: https://youtu.be/lrCoi3gaLfU | lttlrck wrote: | Smartbolts seem to be useful in applications where there is an | expectation the bolts will loosen over time/the maintenance | lifetime, reducing/easing inspection time. | | Similar to the tell-tales used on truck lug nuts: | https://www.dealsonwheels.co.nz/trucks/features/1302/new-tyr... | colordrops wrote: | I need these in my garage door. I wonder how much more | expensive they are. | | Edit: way too expensive. | | https://www.mcmaster.com/smart-bolts/ | lotsofpulp wrote: | $26+ each? Now I am curious which applications it does make | sense to use these in. | [deleted] | blamazon wrote: | Installing to a known torque and painting a line on the | fastener is a lot less expensive, which becomes important | when your project has potentially tens of thousands of key | fasteners, like a bridge. | | But for something like an MRI machine where there's fewer | fasteners and higher stakes - would make a lot of sense to | use Smartbolt I think. | | Tangential: related to trucks, there is a somewhat similar | product to easily monitor tire pressure visually, which is | popular: https://www.linkmfg.com/products/specialty- | products/cats-eye | bumby wrote: | This is a common problem is aerospace with obvious | potential for bad consequences. The general approach is | safety wiring.[1] | | [1] https://en.m.wikipedia.org/wiki/Safety_wire | PaulHoule wrote: | Yeah, a quality torque wrench isn't cheap (particularly the | kind you find in fixed installations like auto repair shops | and factories) but there's got to be some crossover when | you are buying enough bolts that you're better spending | money on tools that are more idiot proof. | [deleted] | throwawayboise wrote: | 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 change a tire? They spin | them on with a pneumatic impact wrench, and then "check" | the torque with a torque wrench. Of course it clicks, | because the nuts are already way too tight. | bumby wrote: | Slipper torque wrenches prevent over tightening | Thlom wrote: | 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 to not tighten too | hard the bolts were stuck next season. Glad the car is | sold and not my problem anymore. | | (I could of course have bought new bolts, but I always | forgot about it after spending 2 hours changing the tires | ...) | enragedcacti wrote: | in English we call that a Cheater bar, so it seems like | that has carried across pretty well :) | | https://en.wikipedia.org/wiki/Cheater_bar | auxym wrote: | Adding on to that, tensioning bolts using torque is | convenient and inexpensive but not very accurate at all. | Some data reproduced in Shigley's Mechanical Engineering | Design showed a +/- 30% variation in tension for properly | torqued bolts, if my memory is correct. | | Emphasis on properly torqued: in the field threads or | bolt heads might be dirty, or torque wrenches might be | out of calibration, adding even more uncertainty. | [deleted] | WalterBright wrote: | If you look at a tire from the side, you can precisely see | the bulge of the tire, which I do all the time to check the | pressure. | [deleted] | ominous_prime wrote: | A problem with installation is that torque is only a proxy | for tension. Torque alone is not incredibly accurate, so | there are a lot of cases that could benefit from an easier | way to accurately indicate tension than by externally | measuring the stretch of the bolt (which often is not an | option) | blamazon wrote: | True, but this caveat is generally pre-empted in design | phase through safety factor principles - multiply certain | design parameters by a coefficient greater than 1 to | account for the inaccuracy in things like torque-tension | correlation. | sokoloff wrote: | Even where you can't measure the stretch directly, | torque-plus-angle is a better way to achieve consistent | stretch than torque alone. | Freak_NL wrote: | Ah; so that's what those are for. I've seen them on lorry | wheels, but never got around to formulating a sensible query | for a search engine. These becoming commonplace seems like a | recent thing (as in last decade or so). | mojomark wrote: | Out of curiosity, on a somewhat related topic, have you tried | nord-lock washers [1] in any of your applications? We looked at | them for a small work boat we designed and built, but they were | a bit pricey and it was just a prototype, so we ended up just | using a dab of lock tight to avoid vibration. Was always | curious to find someone who had practical experience with these | things. I may use them on an upcoming autonomous boat project | where there's nobody around to do rounds and tighten loose | bolts that have shaken loose unexpectedly. | | 1. https://www.nord-lock.com/nord-lock/products/washers/ | auxym wrote: | When I worked on railway vehicles (bogies for passengers | vehicles, more accurately), Nord locks (or equivalent clones) | were standard on all structural joints. | | Especially on a prototype I'd recommend them. Prototypes are | really expensive, a complete supply of Nord locks for your | project is probably less than a single one-off CNC part. | | Note that Nord locks are specced to be single use. Not that | I've never reused some on prototypes, but, well, I'd never do | it on a life-critical joint that is meant to be taken apart | often. | mojomark wrote: | > Nord locks (or equivalent clones) were standard on all | structural joints. | | > Especially on a prototype I'd recommend them. | | > I'd never do it on a life-critical joint that is meant to | be taken apart often. | | Very good/helpful feedback. This thread is giving me much | more confidence to make the extra upfront investment. | Thanks! | blamazon wrote: | I have used Nord-lock washers, they are demonstrated to be | one of, if not the most effective thread locking washer | devices under heavy vibration, but as you say they are quite | pricey. I would certainly recommend them if you have the | time/cost budget, especially for something like an autonomous | boat where vibration is expected and routine inspection is | challenging or impossible. | | When I've used them, it's been for critical fasteners where | ease of assembly was important, and could not be effectively | decoupled from vibration, and where our recommended | inspection/maintenance cycle was not guaranteed. | | You might also consider something like a pinned castle nut, | or safety wire, etc. These are not as simple to specify or | install but more cost effective. Also, I've seen safety wire | used as a conductive link to detect failure in a remote | application. | rsync wrote: | "I have used Nord-lock washers, they are demonstrated to be | one of the most effective thread locking devices under | heavy vibration, but as you say they are quite pricey." | | Which is odd, given their simplicity and ease of | manufacture, etc. | | Can you get them stainless or just HDG ? | blamazon wrote: | You can get them in various stainless alloys. My | understanding is they have a really defensible patent. | auxym wrote: | Their patent might have expired? Im not aware of the | situation but these seem to be an identical product: | https://heico-lock.us/ | mojomark wrote: | > I would certainly recommend them | | > When I've used them, it's been for critical fasteners | where ease of assembly was important, and could not be | effectively decoupled from vibration, and where our | recommended inspection/maintenance cycle was not | guaranteed. | | Taken to heart - sincerely appreciate the insight! | smegsicle wrote: | Their promotional video on the Junker test is pretty cool: | https://yewtu.be/watch?v=IKwWu2w1gGk | taneq wrote: | The thing about torques is that they're often written into | safety standards, and safety standards often have to explicitly | detail how critical values are measured. So until fancy bolts | are recognised in the current standards as best practice for | confirming correct torquing (are they? I dunno), it's gonna be | really hard to get them into production. | pimlottc wrote: | > I'm a mechanical engineer - smartbolts are cool but rarely | used in my experience. Much more commonly used are DTI washers: | https://en.m.wikipedia.org/wiki/Direct_tension_indicator | | Here's an (old) video showing how DTIs work: | | https://www.youtube.com/watch?v=s677UKFiRdA&t=60s | maxmcd wrote: | Nice video of the colored goo in action: | https://youtu.be/5BMQE5XnKww?t=372 | | Breakaway bolts are discussed/demonstrated a few seconds | earlier. | blamazon wrote: | Fireball Tool is a great YouTube channel! I recommend it for | any hackers interested in fabrication. The content is very | approachable. | jcims wrote: | Thanks for the link, looks like a great channel! | kortex wrote: | Release the schmoo! | | That is pretty neat. The Wikipedia page on DTI does a pretty | poor job of describing how they work, so thank you for the | visual. | mc32 wrote: | I'm not an ME or anything, but it would seem washers attest to | pressure (tension) at some point in time (when the nut was | tightened -unless the washer is "springy", which I doubt as it | seems it simply yields at some point), whereas smartbolts | attest to the tension when you look at them --so during | maintenance and not only during installation, so from that PoV, | they are more useful (informative). | blamazon wrote: | 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 at install time. But | many projects that have importantly torqued fasteners | (bridges, buildings, rollercoasters) have certified | inspectors anyway... which is why smartbolts are a niche | product I think. | | Speaking to the trust problem - if you trust the operator of | the torquing install device, you don't need fancy torque | indication at all, just mark the paint line at install. That | is the most cost effective. | mc32 wrote: | Yes, that seems like a cheaper option; however, I think | when you have constant stresses over time, bolts can | stretch or simply parts can wear over time and a paint | score or even a frozen nut won't reveal lessened tension. | Though maybe in this case the issue would have become a | concern way before the bolts start to indicate a problem? | blamazon wrote: | Interestingly that has kind of moved upstream to a design | phase consideration in modern times due to the incredible | depth of understanding we have about materials. | Structures can be designed such that their expected | loading will not stress fasteners beyond their 'yield | strength', which is well characterized. | | Fatigue complicates the analysis, but we understand that | too nowadays, although that is an understanding forged by | many unfortunate consequences, such as: | https://en.m.wikipedia.org/wiki/Aloha_Airlines_Flight_243 | mc32 wrote: | Maybe the following has been designed out; however, I've | on occasion seen the following wear pattern which | compromises the initial strength of a fastener (usually | due to friction over time): | _ _ _______| | _| |__/ | | | ______ | |_ ____/ |_| |_| | blamazon wrote: | First, I love the plain text diagram! (Edit: not fatigue) | This failure should be predictable during the design | phase and that fastener is either wrongly specified or | should have a recommended number of cycles after which it | should be inspected and replaced if found to be out of | specification. | | Of course, many items in our built world do not receive | the same level of design scrutiny as I would wish, nor | the maintenance regime... | auxym wrote: | Unless I'm misunderstanding the diagram, it does not look | like fatigue at all but rather yielding from shear | loading. | | The definition of fatigue is a small crack (in fact | microscopic in the beginning) that grows through the | application of cyclical loading (typically about 10k | cycles is the lower bound for high cycle fatigue, which | does not involve macro yielding). | | Thus a fatigue failure would look like a fully ruptured | part , usually with two distinct zones of the fracture | face: one smooth zone from crack growth ( sometimes with | characteristic "beach marks") and the final sudden | rupture which is usually rough. | | https://en.m.wikipedia.org/wiki/Fatigue_(material) | mc32 wrote: | What I was trying to convey, which I didn't do well in | the diagram, was you have a bolt holding two plates | together or a splice, and you have wear on the bolt shank | -not necessarily shearing. | blamazon wrote: | You are correct, I had a brain fart. | lbhdc wrote: | The paint line is the most common method I have seen. I was | an inspector and for fasteners in a critical load path we | would use an ultrasound machine to measure the length of | the bolt (these were installed in flange like connections). | We would measure them when first installed and compare | measurements after that piece of equipment was used. | | For really critical components we would disassemble them | after every use and would perform multiple tests on each | piece including fasteners. | mrjin wrote: | 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? | usrusr wrote: | 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 for attention state in red seems | nicely intuitive at first glance, but given the market they | serve they should be far more concerned with false | negatives than with false positives and I imagine that it | would be very easy for dirt or bad lighting to make a red | indicator remain unnoticed in an inspection. Perhaps the | color choice is an inherent property of the chemistry | involved? | samstave wrote: | Just curious = how do these SmartBolts handle under full | tension load AND fire conditions... | | You have effectively drilled out the core of a bolt and | replaced it with "goo" and you are using this as an indicator | of the health of that fastening node? | | So what if you burn out the goo? What if you get | side/compression damage on the device -- what does the thing do | when you over-tight/strip? | | isnt a "goo core" less structurally strong than a solid bolt? | Is a bolt tightened to a setting using a SmartBolt vs a regular | bolt with tension wrench going to manage the same loads or not? | avianlyric wrote: | > isnt a "goo core" less structurally strong than a solid | bolt? | | Yes, the oil used in the centre offers zero structural | support. | | > Is a bolt tightened to a setting using a SmartBolt vs a | regular bolt with tension wrench going to manage the same | loads or not? | | Depends on what the original bolt is made out of, and what | the SmartBolt is made out of. Two different bolts are always | going to have different properties, it up to the designer to | match the size and strength of the bolt to their application. | You would need to validate you design with SmartBolts to | ensure they have the properties demanded by your application, | you wouldn't just swap normal bolts for SmartBolts without | making sure SmartBolts were at least as strong as the | original bolts. | JKCalhoun wrote: | The idea has been around since at least 1971. | | https://archive.org/details/PopularMechanics1971/Popular%20M... | asah wrote: | (not an engineer) I watched the video - smartbolts seem a lot | more time & labor efficient and can be tested visually? | dominicdoty wrote: | I've always liked ultrasonic bolt length measurement as the ultra | high reliability way of measuring preload. | | It can also be used for confirming the correct preload is still | present, with the downside of having to track the original length | of every fastener (which isn't really a big deal in high | reliability applications) | rsync wrote: | I consult with a seismic expert at UC Berkeley about once | yearly and he's pretty cavalier about pre-loading ... | | Which is to say, he wants me to "pre-load the shit out of it". | | Which is to say, our "indicator" is that we start to bend the | HDB with the threaded rod. For instance, if we have two of | these, horizontally, on either end of threaded rod: | | https://www.strongtie.com/boltedholdowns_holdowns/hdb_holdow... | | ... he tells me to tighten that threaded rod between them until | we just start to see the hold downs bend (toward each other). | | So, not very scientific at all, but easy to tell that you're | pre-loaded ... | noughtme wrote: | Some crazy canuck cut one in half to show how they (don't) work: | | https://www.youtube.com/watch?v=ClPwlpa86bY | arminiusreturns wrote: | Really informative comment on that video: | | "Nice video. Couple of points: 1: As per the title of your | video, its worth emphasizing that these are tension indicating | bolts, not torque indicating bolts. 2: With any bolted | connection its the tension that is important. Whilst torque and | tension should be correlated, that relationship varies | considerably from bolt to bolt, lubricant to lubricant, hot to | cold, state of corrosion etc... 3: So a bolt torqued to say | 100NM may well have a tension variance of over 100%. The result | is that bolts are often over or under tensioned, which can | compromise the entire bolted connection. 4: Bolts like this | (I've personally used Rotabolts, which are similar in concept | but in my opinion better as they rely on a mechanical | indication rather than a subjective color hue.) are very useful | for certain applications, for example, sub-sea connections | where divers have limited time and feeling, and sea conditions | affect the bolt lubrication. 5: Other uses are for ensuring | correct bolted connections on sensitive flanges, again offshore | and sub-sea sees a lot of this. 6: Bolts like this are, in | summary, brilliant for when you need a good quality bolted | connection with correctly tensioned bolts. For most | applications however they are unnecessary. Keep up the good | work! :-)" - drawingboard82 | | Side note: youtube mobile when I tried to copy the comment | wants me to sign in, to just copy a comment! wtf youtube! I | just opened it in newspipe instead and copied from there | xyzzyz wrote: | One thing missing here, but talked about (albeit not very | clearly) in the video is that it's not even a tension | indicator, but rather, _extension_ indicator. As long as we | are in elastic regime, tension and extension are the same | thing (Hooke's law). However, once you go beyond it, tension | goes down even as extension goes up. This is what the canuck | meant when he talks about people tightening the loose bolt by | giving it extra tweak, around minute 3:40 in the video. Once | you leave the elastic regime, the bolt holding strength is | permanently reduced, and by periodic tightening, sooner or | later you'll see it yield altogether. | connor4312 wrote: | When you said "some crazy canuck", I immediately knew it must | be AvE | hinkley wrote: | 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. | ycIsGarbage wrote: | Most dirt isn't red though. I'd worry more about dirt | _obscuring_ the red and making it look black. | hinkley wrote: | Look at the pictures on the website and I think you'll follow | me. | | I was thinking of brown specifically but black has the same | effect. When it's partially covered the color will be the | average of the two. Probably black if it's near pavement, | brown if exposed to nature. | dmkolobov wrote: | I was one of the folks who put together the steel for a | waterslide in a certain amusement park in California. Our method | consisting of putting a mark across the bolt and nut after | tightening it all the way down with a spud wrench, and then using | a breaker bar until the mark on the nut was at the 4 o'clock | position( or maybe it was 8, I don't recall ). | | The inspectors would then use a telescope to check every mark. | Completely blew my mind that they relied on this method, rather | than something that measured the force directly. | choonway wrote: | or you could use a drone with a sufficiently zoomed in and | stabilized camera. | dmkolobov wrote: | Totally, but the crazy part is that there is nothing | preventing you from making these marks without following the | appropriate tightening procedure. When the project is several | months late and people are working 16 hour days, the | temptation to cut corners is high. | hinkley wrote: | > making these marks without following the appropriate | tightening procedure | | If you didn't torque the bolt tight enough then it will | come loose sooner, and the lines won't line up. I'm sure | there are situations where the torque of the bolt is | critical for handling peak load on the system, but for a | lot of situations where a torque wrench keeps you from | damaging by over-tightening, and makes sure you got it | tight enough that it stays tight. | | I should say there's one other failure mode a torque wrench | can test that that the paint doesn't by itself, and that's | a failing bolt. If you've ever seen a broken bolt, and the | entire surface isn't uniformly shiny, then you've seen a | bolt that cracked a long time ago and then failed recently. | That crack is going to show up as less torque. So if the | bolt hasn't spun but the torque has dropped, you might have | a problem, rather than having a freak incident where the | nut spun exactly 360deg since you checked it last. | | I could see an argument for using paint and smartbolts for | fasteners with epic failure modes, like people dying or | generators exploding. | dmkolobov wrote: | Is it standard for there to be a follow-up bolt | inspection some time after the initial assembly? This was | a one-time gig for us, as we were welders by trade and | boss-man got the contract from a family friend, so I'm | not familiar with inspection standards. | | For what it's worth, we tightened all the bolts down | according to the procedure, despite pressure from boss- | man to do otherwise for a few of them. | hinkley wrote: | I haven't wrenched professionally for anything bigger | than a bicycle, and in that case one of the most | expensive components (labor and parts) can be damaged | immediately by too much torque or over time by not | enough, so you did not want to do that without a torque | wrench. Or at least not until you had muscle memory for | what 'enough' felt like. | | On bikes, car repair and a few other items, mine and | others, I've seen sheared off bolts. In at least two of | those I was involved with the tightening prior to | failure, and the lightbulb moment where we figured out | why the sequence of events made sense. | dalrympm wrote: | I would love to see these on chair lifts. I wonder if the | indicators can remain valid with the types of temperature swings | you see on a ski mountain. | rsync wrote: | In my experience, the most common safety practice on chairlift | (poles) is a double-nut. It's very common to see all through | North America - no washer, just two nuts stacked. | | I've never inspected them to see if they have indicators | painted on, etc. - one would assume they should ... | dalrympm wrote: | I've also noticed that the nuts go on top. I've always | wondered if this was so it was completely obvious if a bolt | dropped out (i.e. sunlight coming through the hole). | sfifs wrote: | Seems like something that would be very useful for furniture or | mechanisms that are self assembled like Ikea, chairs etc by | regular people. Easy visual inspection when things are loose. | ycIsGarbage wrote: | Way too expensive for that kind of application. | karaterobot wrote: | It's annoying that, as you scroll down the page, the bolt | animates to show it turning, but it scrolls out of view before it | gets to the point where the _main feature of the product would be | shown_. | disposableuname wrote: | Not just me, then. I played around with scroll, with zoom, | doing everything I could to try to see the actual main feature. | alhirzel wrote: | This reminds me of frangibolts: https://www.ebad.com/tini- | frangibolt/ | | Conop: an electric heater temporarily modifies the crystal | structure and axially overloads the bolt, breaking it. We used | these on a satellite that I worked on with deployable panels. | WalterBright wrote: | At Boeing, I learned that bolts should be lubricated before | torquing them in order to ensure an accurate torque. I initially | thought wouldn't the lubrication allow the bolt to unwind itself? | Surprisingly, no. | | Since then, on my car, I always put a bit of grease on a bolt | beforehand. It keeps the water out, preventing the bolt from | rusting itself together. It makes for an accurate torque. I've | never had one unscrew itself, and I can always get the lug nuts | off! | | Of course, you still need to use lock washers. For critical | bolts, use a cotter pin or a safety wire. | smiley1437 wrote: | I've always read that lubricating the threads can cause over- | tensioning of the bolt if you torque it to the (typically) | unlubricated torque spec: | | https://www.engineeringtoolbox.com/torque-lubrication-effect... | | If you are measuring the bolt tension directly then it doesn't | matter but torque is only a proxy for tension. | globular-toast wrote: | I grease all the threads on my bicycle ever since I had a | bottom bracket seize into a frame and lost the frame. I have | heard that you shouldn't grease lug nuts on a car, though. I'm | not sure why, so take it with a a large pinch of salt. It might | be simply because most people don't regularly check the torque | on the nuts and in that case it's more desirable to have them | seize than fail. | WalterBright wrote: | I've been doing this for 40 years. I've never had a lug nut | loosen, or rust in place. | | But this, of course, is anecdotal data. Do what you judge is | best for your situation. | auxym wrote: | Anecdotally, I've been using loctite C5A (copper anti- | seize) on lug nuts for years without an issue. I also | torque them to the manufacturer spec with a torque wrench | twice a year (when I switch summer/winter tires). | frosted-flakes wrote: | I think it's because torque specs for cars assume | unlubricated threads. If you lubricate them and torque them | to spec, you'll overtighten them. | gannon- wrote: | Could be interesting to apply this to crew boats which A) people | are used to paying a lot for the equipment and B) people often | have to assemble and disassemble with bolts, and loose bolts are | certainly a point of failure during a race. | hexnuts wrote: | We need self sealing stem bolts. | jamesakirk wrote: | Got anything to trade for them? | tadfisher wrote: | Just 500 liters of yamok sauce. | moreati wrote: | In the UK (and elsewhere?) Lorry tyres have plastic caps on the | bolts, with arrows aligned to each other in pairs, or some | regular pattern. It's easy to see at a glance if a bolt has | loosened. | | e.g. https://mechanics.stackexchange.com/questions/29690/what- | are... | GistNoesis wrote: | I am surprised there aren't already some chip for it, or is there | ? | | Something based on RF-energy harvesting, you beam it with radio | waves, it uses the energy to take a pressure measurement and send | you back the result, along with the id of the bolt. And you | inspect all your factory bolts in a matter of seconds, and | everything is nicely logged, even those hard to inspect bolts. | | To measure the pressure either some piezo-resistance, or some | capacive-sensing between two washer separated by a squeezie | dielectric (Could a FR4 pcb-washer hold the pressure ?), or an | integrated MEMS-pressure sensor. | | If your technician needs to tighten the bolt, he has to get close | so he can transmit more RF energy so you can even have a led, | that could turn on when the pressure is right. | Breadmaker wrote: | there is: IoT bolts | https://news.ycombinator.com/item?id=29123301 | thom wrote: | No pricing on the site, but I hope it's in the region of five | thousand wrappages of Cardassian yamok sauce for a hundred gross. | oneplane wrote: | I think the bolts listed in the article are less expensive than | self-sealing stem bolts. | jrockway wrote: | They're "contact us for pricing" which basically means you | can't afford them. ___________________________________________________________________ (page generated 2021-12-31 23:00 UTC)