We need self sealing stem bolts.
Got anything to trade for them?
Just 500 liters of yamok sauce.
Smartbolts
81–90 of 150 posts
Re: Smartbolts
#82I’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…
(not an engineer) I watched the video - smartbolts seem a lot more time & labor efficient and can be tested visually?
Re: Smartbolts
#83Earlier quoted context omitted.
"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 ?
You can get them in various stainless alloys. My understanding is they have a really defensible patent.
Their patent might have expired? Im not aware of the situation but these seem to be an identical product: https://heico-lock.us/
Re: Smartbolts
#84This 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.
Re: Smartbolts
#85Earlier quoted context omitted.
> 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.
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.
Re: Smartbolts
#86Earlier quoted context omitted.
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.
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).
Re: Smartbolts
#87If 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.
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.
Re: Smartbolts
#88Earlier quoted context omitted.
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…
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 crit…
> 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!
Re: Smartbolts
#89Earlier 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…
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 …)
Re: Smartbolts
#90Earlier quoted context omitted.
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…
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 o…
> 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!