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Smartbolts

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Re: Smartbolts

#71

Post by globular-toast »

WalterBright wrote: post #69

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 its…

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.

Re: Smartbolts

#72

Post by ycIsGarbage »

hinkley wrote: post #67

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.

Most dirt isn't red though. I'd worry more about dirt obscuring the red and making it look black.

Re: Smartbolts

#73

Post by bumby »

blamazon wrote: post #8
lttlrck wrote: post #6

Earlier quoted context omitted.

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...

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 moni…

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

Re: Smartbolts

#74

Post by WalterBright »

globular-toast wrote: post #71
WalterBright wrote: post #69

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 its…

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.

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.

Re: Smartbolts

#75

Post by [deleted] »

WalterBright wrote: post #70
blamazon wrote: post #8

Earlier quoted context omitted.

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 moni…

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]

Re: Smartbolts

#76

Post by bumby »

throwawayboise wrote: post #61
PaulHoule wrote: post #12

Earlier quoted context omitted.

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.

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…

Slipper torque wrenches prevent over tightening

Re: Smartbolts

#77

Post by [deleted] »

auxym wrote: post #24
PaulHoule wrote: post #12

Earlier quoted context omitted.

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.

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 uncertaint…

[deleted]

Re: Smartbolts

#78

Post by dmkolobov »

hinkley wrote: post #68
dmkolobov wrote: post #66

Earlier quoted context omitted.

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.

> 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 enoug…

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.

Re: Smartbolts

#79

Post by gannon- »

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.

Re: Smartbolts

#80

Post by smegsicle »

mojomark wrote: post #17
blamazon wrote: post #3

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 re…

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 autonomou…

Their promotional video on the Junker test is pretty cool: https://yewtu.be/watch?v=IKwWu2w1gGk
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