7 ms·

I'm a former mechanical engineer specializing in fastening (now I'm a Javascript developer). It's certainly interesting that they're managing to keep the tight

by roneesh 12y ago

I'm a former mechanical engineer specializing in fastening (now I'm a Javascript developer). It's certainly interesting that they're managing to keep the tightness up without resorting to any truly strange designs. However as some have noted, cost will keep it from being adopted. Let's face it, fastening is the last thing considered in a project and the last thing bought. Even for large projects it's at most a few percent of budget and people are desperate to limit it's cost as much as possible. Also, truly there's no need for a product like this unless the stress on the bolt, nut and what's being fastened have to be manage just perfectly. Otherwise the simplest solution to relaxation is just tightening more. Then it relaxes to an appropriate stress. Almost all bolts in the world are under-tightened. Greater analysis of the joint you're tightening rather than a fancier nut will pay off many more dividends. Let me clarify. I applaud the effort, fastening needs research and development badly, but this is no miracle nut, rather it's a specialized application.

S_A_P 12y ago
So are you saying that most people would think its nuts to spend so much on a fastener?
- S_A_P 12y ago
  Lesson learned. Never make bad engineering puns lest you feel the wrath of the downvote onslaught.
MrDosu 12y ago
So you are also saying as a former mechanical engineer there are no applications were tighter nuts are needed? Well personally I know a few scenarios were the nut has keep steady when its hard to do. But for that case I prefer two nuts stacked on top of each other.
- bronson 12y ago
  They're called jam nuts and they're a nightmare in production. These days I think they're only used where the application isn't critical, the labor is skilled and underpaid, and you're fresh out of lock washers and nylocks.
  - vonmoltke 12y ago
    I haven't seen jam nuts used outside of construction in a long time.
_almosnow 12y ago
"Almost all bolts in the world are under-tightened." You learn something new everyday.
- nullterminated 12y ago
  I don't wanna alarm ya, but scientists say forty percent of America's pictures... are hanging crooked.
tjradcliffe 12y ago
I agree it's a little specialized and likely quite pricy, but as a sometime roboticist this kind of innovation makes me hopeful. Fasteners and connectors are unsolved problems, and robotics is plagued with such issues. Even an expensive solution for a few critical points would be valuable. Loc-tite works OK most of the time, but the ideal is a nut that actually stays tight all by itself.
- kcorbitt 12y ago
  A sincere question from another part-time (hobbyist) roboticist: what problems do you have with loosening that nylock[1] nuts don't solve? [1] https://www.google.com/search?q=nylock+nut&espv=2&source=lnms&tbm=isch&sa=X&ei=nAJhVN7mDurIsAS3jYKgAQ&ved=0CAcQ_AUoAg&biw=1280&bih=678 https://www.google.com/search?q=nylock+nut&espv=2&source=lnm...
  - bradfa 12y ago
    Likely high temperatures and/or chemical resistance, maybe very high tightening torques or force, but possibly others, too. Mostly more specialized fastening, I would guess. But think about the bolts and nuts that hold the exhaust system to a car engine. Temperatures are going to be very high and nylon wouldn't withstand those temperatures. Things like that.
    - mhb 12y ago
      Lock washers?
      - swimfar 12y ago
        According to a NASA fastener design manual[1](page 9) split-ring style lock washers are useless for locking purposes. They say that star washers do proved some additional friction/locking action, but at the cost of damage to the surface(the friction comes from digging into the surface). [1] http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900009424.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1990000...
lotsofmangos 12y ago
truly there's no need for a product like this unless the stress on the bolt, nut and what's being fastened have to be manage just perfectly. Engine blocks.
- msandford 12y ago
  Engine blocks aren't all that crazy. Most of the time (at least these days) they're made out of aluminum. That means that the stress on the bolt is limited more by the aluminum threads that the bolt mates with rather than by the bolt itself. Further engine blocks are pretty cheap, all things considered. Turbines have tighter engineering constraints and wider price constraints so I would look there before looking at reciprocating ICEs.
  - tsomctl 12y ago
    So why are blown head gaskets such a problem?
    - msandford 12y ago
      Blown head gaskets have a lot less to do with bolt torque and a lot more to do with a lot of stuff all going on at roughly the same place. If they didn't separate combustion from coolant and both of those from oil, they would fail a lot less. Yes the bolts must be torqued properly but that has more to do with ensuring that even pressure is applied across a huge gasket face than anything to do with the bolts self-loosening. If the heads on an engine were steel and much thicker you could do the same job with a couple of bolts instead of a dozen. If an auto manufacturer was enterprising they could probably move some of the oil passages away from the coolant and combustion (which by their nature need to be close to one another) and they could make cavities for o-rings and seal the oil from the coolant a lot more effectively. But the failure rate for head gaskets is fairly low already and that would be adding a fair amount of cost and fiddly-ness to a not-that-big problem. When I say "fairly low" what I mean is that it might comprise 10% of engine failures but engine failures are already pretty rare, so 10% of 1% isn't all that big of a deal. Those are made-up numbers, btw, so don't crucify me if they're wrong.
ssharp 12y ago
I vaguely remember seeing a TV show on amusement parks and thought that mechanics had to check and tighten every every bolt on a roller coaster rather frequently. I wonder if this type of nut would result in any labor savings for them?
- moepstar 12y ago
  Probably not, as they still might need to be checked periodically... At least, that's what i want them to do :P
- marvin 12y ago
  I don't know a lot about mechanical engineering, but at least in many aviation applications, the issue of nuts coming loose is resolved with a split pin that is bent into a locking shape after the nut has been tightened. http://www.technologystudent.com/joints/comnut1.htm http://www.technologystudent.com/joints/comnut1.htm Of course, this adds some extra overhead when disassembling the part, but the nut won't come loose unless there's a different problem (e.g. corrosion).
  - chii 12y ago
    could the force that is trying to loosen the nut bend the split pin? would the self-tightening bolt perform better in this situation under the same condition?
inthewoods 12y ago
What would be a miracle nut? Is it just about cost?
TehCorwiz 12y ago
You're correct in that for applications of limited complexity it's not likely cost effective. However we don't know what the premium is over traditional fasteners. It's also probable that in an assembly with many fasteners it may be cost advantageous to just use a product that solves the problem, rather than spend time and money on man-hours and possible production delays.
cdr 12y ago
> However as some have noted, cost will keep it from being adopted. Let's face it, fastening is the last thing considered in a project and the last thing bought. Even for large projects it's at most a few percent of budget and people are desperate to limit it's cost as much as possible. This is incredibly true IME. When I was working at Xerox, they were in the process of switching to vastly inferior fasteners just to save a couple bucks per $500K machine.
awkward 12y ago
As a cyclist who does my own maintenance as a hobby, I am pretty willing to pay retail-type prices on exotic hardware that requires less effort on my part and is more reliable on the road. Not the biggest market, sure, but it's a market where you could very plausibly sell a single fastener for ten-plus dollars with the right marketing.
- noir_lord 12y ago
  Also a cyclist, biggest issue I have is getting things to the correct torque as carbon fibre can be a bit of a bugger, I can't recall anything coming lose on my bike in a long time though. I doubt I'd buy a 10 dollar but either but if you marketed it as aero I know some who would ;)
- chii 12y ago
  i suppose if they market it right, such a boutique style use-case is viable. But i doubt it'd be all _that_ profitable...i m going to guess it's going to be a family style business at best.
MertsA 12y ago
This could mean a lot for suspension components like spindle nuts where torque is so critical. Not only would that potentially mean no more cotter pins and staking the nut to the spindle, the preload on a wheel bearing would be more precise potentially leading to an increased MTTF just by using a different fastener.

by roneesh 12y ago

S_A_P 12y ago

So are you saying that most people would think its nuts to spend so much on a fastener?

S_A_P 12y ago
Lesson learned. Never make bad engineering puns lest you feel the wrath of the downvote onslaught.

MrDosu 12y ago

So you are also saying as a former mechanical engineer there are no applications were tighter nuts are needed? Well personally I know a few scenarios were the nut has keep steady when its hard to do. But for that case I prefer two nuts stacked on top of each other.

bronson 12y ago
They're called jam nuts and they're a nightmare in production. These days I think they're only used where the application isn't critical, the labor is skilled and underpaid, and you're fresh out of lock washers and nylocks.
- vonmoltke 12y ago
  I haven't seen jam nuts used outside of construction in a long time.

_almosnow 12y ago

"Almost all bolts in the world are under-tightened." You learn something new everyday.

nullterminated 12y ago
I don't wanna alarm ya, but scientists say forty percent of America's pictures... are hanging crooked.

tjradcliffe 12y ago

I agree it's a little specialized and likely quite pricy, but as a sometime roboticist this kind of innovation makes me hopeful. Fasteners and connectors are unsolved problems, and robotics is plagued with such issues. Even an expensive solution for a few critical points would be valuable. Loc-tite works OK most of the time, but the ideal is a nut that actually stays tight all by itself.

kcorbitt 12y ago
A sincere question from another part-time (hobbyist) roboticist: what problems do you have with loosening that nylock[1] nuts don't solve? [1] https://www.google.com/search?q=nylock+nut&espv=2&source=lnms&tbm=isch&sa=X&ei=nAJhVN7mDurIsAS3jYKgAQ&ved=0CAcQ_AUoAg&biw=1280&bih=678 https://www.google.com/search?q=nylock+nut&espv=2&source=lnm...
- bradfa 12y ago
  Likely high temperatures and/or chemical resistance, maybe very high tightening torques or force, but possibly others, too. Mostly more specialized fastening, I would guess. But think about the bolts and nuts that hold the exhaust system to a car engine. Temperatures are going to be very high and nylon wouldn't withstand those temperatures. Things like that.
  - mhb 12y ago
    Lock washers?
    - swimfar 12y ago
      According to a NASA fastener design manual[1](page 9) split-ring style lock washers are useless for locking purposes. They say that star washers do proved some additional friction/locking action, but at the cost of damage to the surface(the friction comes from digging into the surface). [1] http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900009424.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1990000...

lotsofmangos 12y ago

truly there's no need for a product like this unless the stress on the bolt, nut and what's being fastened have to be manage just perfectly. Engine blocks.

msandford 12y ago
Engine blocks aren't all that crazy. Most of the time (at least these days) they're made out of aluminum. That means that the stress on the bolt is limited more by the aluminum threads that the bolt mates with rather than by the bolt itself. Further engine blocks are pretty cheap, all things considered. Turbines have tighter engineering constraints and wider price constraints so I would look there before looking at reciprocating ICEs.
- tsomctl 12y ago
  So why are blown head gaskets such a problem?
  - msandford 12y ago
    Blown head gaskets have a lot less to do with bolt torque and a lot more to do with a lot of stuff all going on at roughly the same place. If they didn't separate combustion from coolant and both of those from oil, they would fail a lot less. Yes the bolts must be torqued properly but that has more to do with ensuring that even pressure is applied across a huge gasket face than anything to do with the bolts self-loosening. If the heads on an engine were steel and much thicker you could do the same job with a couple of bolts instead of a dozen. If an auto manufacturer was enterprising they could probably move some of the oil passages away from the coolant and combustion (which by their nature need to be close to one another) and they could make cavities for o-rings and seal the oil from the coolant a lot more effectively. But the failure rate for head gaskets is fairly low already and that would be adding a fair amount of cost and fiddly-ness to a not-that-big problem. When I say "fairly low" what I mean is that it might comprise 10% of engine failures but engine failures are already pretty rare, so 10% of 1% isn't all that big of a deal. Those are made-up numbers, btw, so don't crucify me if they're wrong.

ssharp 12y ago

I vaguely remember seeing a TV show on amusement parks and thought that mechanics had to check and tighten every every bolt on a roller coaster rather frequently. I wonder if this type of nut would result in any labor savings for them?

moepstar 12y ago
Probably not, as they still might need to be checked periodically... At least, that's what i want them to do :P
marvin 12y ago
I don't know a lot about mechanical engineering, but at least in many aviation applications, the issue of nuts coming loose is resolved with a split pin that is bent into a locking shape after the nut has been tightened. http://www.technologystudent.com/joints/comnut1.htm http://www.technologystudent.com/joints/comnut1.htm Of course, this adds some extra overhead when disassembling the part, but the nut won't come loose unless there's a different problem (e.g. corrosion).
- chii 12y ago
  could the force that is trying to loosen the nut bend the split pin? would the self-tightening bolt perform better in this situation under the same condition?

inthewoods 12y ago

What would be a miracle nut? Is it just about cost?

TehCorwiz 12y ago

You're correct in that for applications of limited complexity it's not likely cost effective. However we don't know what the premium is over traditional fasteners. It's also probable that in an assembly with many fasteners it may be cost advantageous to just use a product that solves the problem, rather than spend time and money on man-hours and possible production delays.

cdr 12y ago

> However as some have noted, cost will keep it from being adopted. Let's face it, fastening is the last thing considered in a project and the last thing bought. Even for large projects it's at most a few percent of budget and people are desperate to limit it's cost as much as possible. This is incredibly true IME. When I was working at Xerox, they were in the process of switching to vastly inferior fasteners just to save a couple bucks per $500K machine.

awkward 12y ago

As a cyclist who does my own maintenance as a hobby, I am pretty willing to pay retail-type prices on exotic hardware that requires less effort on my part and is more reliable on the road. Not the biggest market, sure, but it's a market where you could very plausibly sell a single fastener for ten-plus dollars with the right marketing.

noir_lord 12y ago
Also a cyclist, biggest issue I have is getting things to the correct torque as carbon fibre can be a bit of a bugger, I can't recall anything coming lose on my bike in a long time though. I doubt I'd buy a 10 dollar but either but if you marketed it as aero I know some who would ;)
chii 12y ago
i suppose if they market it right, such a boutique style use-case is viable. But i doubt it'd be all _that_ profitable...i m going to guess it's going to be a family style business at best.

MertsA 12y ago

This could mean a lot for suspension components like spindle nuts where torque is so critical. Not only would that potentially mean no more cotter pins and staking the nut to the spindle, the preload on a wheel bearing would be more precise potentially leading to an increased MTTF just by using a different fastener.