8 ms·

Self-tightening nut that provides tight fastening with a unique screw thread

152 points by dmmalam 12y ago

graeham 12y ago
Or you can just use two regular nuts http://en.wikipedia.org/wiki/Jam_nut http://en.wikipedia.org/wiki/Jam_nut
- BetaCygni 12y ago
  Yes, but that takes more space and is much harder to fasten correctly. This actually looks like a good product.
  - pp19dd 12y ago
    The RepRap 3D printer I assembled used lots of these (Jam Nuts), and I can confirm that it was very annoying to keep making geometric adjustments. The instructions were - assemble loose to keep general structure, then tighten to exact fit, and then tighten to keep that fit. I ended up buying 4 wrenches to make my job easier.
cfontes 12y ago
Would this solve the lose holds problem on climbing gyms? Where the holds because of the constant pulling and tension unscrew themselves form the wall and start to rotate, until some unlucky bastard goes for it...
- roneesh 12y ago
  The only solution to the problem which I would trust would be continuous maintenance and a design that doesn't rely on thread strength to maintain a joint.
  - pbhjpbhj 12y ago
    Yes, all holds need testing but it's reduces the maintenance cost if the holds don't need tightening all the time, surely? Also if the expectation value for loosening is lower per unit time it means there is less likelihood (other values being constant) that the hold has loosened since testing, with the same testing regime that makes it safer so far as I can see.
    - bronson 12y ago
      Since the customers typically tighten loose holds themselves, I would guess that the maintenance cost is vanishingly small. It's definitely safer than a plain nut, agreed, but is it noticeably safer than any of the other thread locking solutions out there?
- bronson 12y ago
  Nope! There's no way any climbing gym would rebuild its walls to be full of expensive proprietary nuts. If they cared, they could use loctite or lock washers. It seems there's very little money in fixing spun holds.
  - blhack 12y ago
    Climbing gyms change their "routes" pretty frequently, so I don't think they would use locktite.
    - DanBC 12y ago
      You get different grades of Loctite. Climbing walls don't get that much vibration but a thread-locking product would provide some reassurance.
    - bronson 12y ago
      Why? Loctite Blue is meant to be disassembled and reassembled: http://www.loctiteproducts.com/p/t_lkr_blue/overview/Loctite-Threadlocker-Blue-242.htm http://www.loctiteproducts.com/p/t_lkr_blue/overview/Loctite... Gyms clearly don't use loctite, but I think it's just because the problem doesn't warrant the slight increase in mess and hassle.
      - blhack 12y ago
        Ah, okay. I thought locktite was only a "mostly permanent" adhesive. Thanks for the info!
- peterwwillis 12y ago
  If you want to become a climbing gym-supplying tycoon and fix this problem, invent a new connector for holds based on a carabiner's autolock. You could pop the hold into a pre-set receptacle and it could spring closed, and a special tool could go into the bolthole to release the spring lock and pop the hold off the wall. No more re-tightening + faster route setting, and based on existing technology. Would probably cost the same as this special bolt, but provides enough extra features that a gym might rationalize the price.
VLM 12y ago
If you're bored, try to find anything other than journalist sites reporting on this. I spent at least five minutes searching and couldn't find anything other than that. Weird. I was hoping to find the mfgr or a data sheet. My guess, looking at the one pix available, is the threaded portion acts as a spring. If you know how a ballscrew works this is kind of a sleeved sprung version of one. Interesting. Probably a little delicate under high loads. Most likely I'll continue to use nylocks and/or traditional lockwashers when I build things, but its and interesting idea. I wonder how all the patents and trademarks collide vs the "semi-well known" Hytorc nut, which is basically the same idea but with an integral washer at the base. Hytorc's are strange little differentially threaded nuts, so instead of the tension coming from a spring half moon shape, the tension comes from the secondary fine threading. They're kind of expensive, outta my price league, so I'm guessing this new nut is going to be out of my league.
- chromaton 12y ago
  You can see the fine level of finish on the completed display units, which would indicate "expensive" to me as well. Also note that they're going after machining/manufacturing as the target market rather than, say, automotive, where cost is king.
  - acveilleux 12y ago
    As soon as I saw this, I thought of Aerospace applications. Especially things like engine mounts, landing gear assemblies, etc. The expensive but few safety critical fasteners.
    - VLM 12y ago
      I saw it the other way, relying on spring pressure isn't wise from a safety perspective and when it fails parts are going to fall into other parts etc and torques are pretty high on stuff like that which makes me wonder about torque limits on this gadget. Also there's no specs on stuff like sideloads or impact loading or anti-corrosion plating. I'm kinda mystified how this thing could work if cad plated without scraping off the cad plate, so ... Where I do see it making an impact, is "every gram counts" and if you took every washer and lockwasher off an instrument panel and replaced the nuts with these, you might save a small but measurable mass, which translates directly into a small but measurable increase in payload or range or lower fuel consumption or performance. Even on a small plane this might be a pound or two, but imagine a giant jetliner and it adds up to a respectable mass, probably financially a good idea... if its ever aerospace rated. Note that there's kind of big gap between being listed for sale on a foreign web page with no documentation at all and no specs or datasheets or certs, and being COTS at a place like "aircraft spruce and specialties". For laughs I went there and the price to beat for certified aerospace grade locknuts is like 48 cents a piece, so I donno if this new gadget can compete in the aerospace market at the typical 100x price markup... I mean sure saving weight and fuel is cool, but not if each aircraft certified nut costs $500.
JoeAltmaier 12y ago
Could be huge! Just the increased safety margins could be worth the cost - no lawsuits when a grinding head dismounts during operation due to loosening nut or whatever.
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.
jhallenworld 12y ago
Is it cheaper than loctite? A bolt with nut is supposed to work like a kind of high-tension spring pulling the pieces being fastened together. For large safety critical projects there is a technology to directly measure the tension of the bolt so that you know you have tightened the nut enough: http://www.checkline.com/product/TI-MINIMAX http://www.checkline.com/product/TI-MINIMAX This is better than a torque spec (where you don't know the friction exactly, so the bolt tension is an estimate).
- eksith 12y ago
  It may be better than adhesive when repeated removal is necessary. Thread locking fluid is a pain in smaller applications when the material flakes off as you untighten, which you have to clean up afterwards. In a clean-room or other delicate environment, having loose particulates is a big problem.
- vonmoltke 12y ago
  In a vibration-sensitive application, it may be needed in addition to a torque spec. The radar hardware I used to support had either Loctite or locking helicoils on nearly every mechanical attachment point. Our hardware would not have passed our vibe tests without it.
jhallenworld 12y ago
BTW, this "Eng-Tips Forums" is an excellent resource: http://www.eng-tips.com/threadminder.cfm?pid=725 http://www.eng-tips.com/threadminder.cfm?pid=725 (fun to read the nuclear engineering forum..)
lisper 12y ago
Is this actually any better than an ordinary nut with a teflon insert?
bronson 12y ago
I love the idea of a two part nut that cams itself tight. If weight and corrosion isn't a problem, this could see some good applications. Maybe locating on spinning shafts in high heat, or in blind holes? Stage 8 and safety wire seem simpler and they should offer more predictable torque for critical applications. Hoping to see some comparisons to existing solutions and failure analysis.
ha292 12y ago
Future YC startup: "XYZ is the self-tightening bolt to self-tightening nuts"
kazinator 12y ago
Those things look ridiculously well-made. Moreover, the thread is not simply cut in the nut, but rather a threaded insert is joined with the nut casing. That looks like it is more expensive to make, and could be an Achilles' heel if it is botched in production. Suppose a manufacturer cuts costs by using a cheaper metal for the casing, thinking only the threads have to be good quality; but then the nut is easy to strip. What if the two parts expand at different rates under heating. By the way, you can use two nuts to prevent loosening: http://en.wikipedia.org/wiki/Nut_%28hardware%29#Use_of_two_nuts_to_prevent_self-loosening http://en.wikipedia.org/wiki/Nut_%28hardware%29#Use_of_two_n... this could be cheaper than a much more expensive single nut. This article section explains how vibration causes loosening. The second nut ensures that the first nut stays in firm contact with the bolt threads even during moments when the pre-load is momentarily lost due to vibration, and so cannot rotate loose.
Scene_Cast2 12y ago
Saw this on diginfonews a while back, it's a neat concept. There's one thing that might be problematic with this design. The nut has a threaded c-shape insert. Due to the threading, when it is in the "wedged" position, it doesn't just have to close the gap between the tips of the "C" (let's suppose that this deformation is in the horizontal plane), it also has to deform vertically due to the threading. This vertical plus horizontal deformation must be either harsh on the material, require a relatively small amount of "wedge" (reducing the usefulness), or have a complex initial shape in anticipation of this type of deformation.

152 points by dmmalam 12y ago

graeham 12y ago

Or you can just use two regular nuts http://en.wikipedia.org/wiki/Jam_nut http://en.wikipedia.org/wiki/Jam_nut

BetaCygni 12y ago
Yes, but that takes more space and is much harder to fasten correctly. This actually looks like a good product.
- pp19dd 12y ago
  The RepRap 3D printer I assembled used lots of these (Jam Nuts), and I can confirm that it was very annoying to keep making geometric adjustments. The instructions were - assemble loose to keep general structure, then tighten to exact fit, and then tighten to keep that fit. I ended up buying 4 wrenches to make my job easier.

cfontes 12y ago

Would this solve the lose holds problem on climbing gyms? Where the holds because of the constant pulling and tension unscrew themselves form the wall and start to rotate, until some unlucky bastard goes for it...

roneesh 12y ago
The only solution to the problem which I would trust would be continuous maintenance and a design that doesn't rely on thread strength to maintain a joint.
- pbhjpbhj 12y ago
  Yes, all holds need testing but it's reduces the maintenance cost if the holds don't need tightening all the time, surely? Also if the expectation value for loosening is lower per unit time it means there is less likelihood (other values being constant) that the hold has loosened since testing, with the same testing regime that makes it safer so far as I can see.
  - bronson 12y ago
    Since the customers typically tighten loose holds themselves, I would guess that the maintenance cost is vanishingly small. It's definitely safer than a plain nut, agreed, but is it noticeably safer than any of the other thread locking solutions out there?
bronson 12y ago
Nope! There's no way any climbing gym would rebuild its walls to be full of expensive proprietary nuts. If they cared, they could use loctite or lock washers. It seems there's very little money in fixing spun holds.
- blhack 12y ago
  Climbing gyms change their "routes" pretty frequently, so I don't think they would use locktite.
  - DanBC 12y ago
    You get different grades of Loctite. Climbing walls don't get that much vibration but a thread-locking product would provide some reassurance.
  - bronson 12y ago
    Why? Loctite Blue is meant to be disassembled and reassembled: http://www.loctiteproducts.com/p/t_lkr_blue/overview/Loctite-Threadlocker-Blue-242.htm http://www.loctiteproducts.com/p/t_lkr_blue/overview/Loctite... Gyms clearly don't use loctite, but I think it's just because the problem doesn't warrant the slight increase in mess and hassle.
    - blhack 12y ago
      Ah, okay. I thought locktite was only a "mostly permanent" adhesive. Thanks for the info!
peterwwillis 12y ago
If you want to become a climbing gym-supplying tycoon and fix this problem, invent a new connector for holds based on a carabiner's autolock. You could pop the hold into a pre-set receptacle and it could spring closed, and a special tool could go into the bolthole to release the spring lock and pop the hold off the wall. No more re-tightening + faster route setting, and based on existing technology. Would probably cost the same as this special bolt, but provides enough extra features that a gym might rationalize the price.

VLM 12y ago

If you're bored, try to find anything other than journalist sites reporting on this. I spent at least five minutes searching and couldn't find anything other than that. Weird. I was hoping to find the mfgr or a data sheet. My guess, looking at the one pix available, is the threaded portion acts as a spring. If you know how a ballscrew works this is kind of a sleeved sprung version of one. Interesting. Probably a little delicate under high loads. Most likely I'll continue to use nylocks and/or traditional lockwashers when I build things, but its and interesting idea. I wonder how all the patents and trademarks collide vs the "semi-well known" Hytorc nut, which is basically the same idea but with an integral washer at the base. Hytorc's are strange little differentially threaded nuts, so instead of the tension coming from a spring half moon shape, the tension comes from the secondary fine threading. They're kind of expensive, outta my price league, so I'm guessing this new nut is going to be out of my league.

chromaton 12y ago
You can see the fine level of finish on the completed display units, which would indicate "expensive" to me as well. Also note that they're going after machining/manufacturing as the target market rather than, say, automotive, where cost is king.
- acveilleux 12y ago
  As soon as I saw this, I thought of Aerospace applications. Especially things like engine mounts, landing gear assemblies, etc. The expensive but few safety critical fasteners.
  - VLM 12y ago
    I saw it the other way, relying on spring pressure isn't wise from a safety perspective and when it fails parts are going to fall into other parts etc and torques are pretty high on stuff like that which makes me wonder about torque limits on this gadget. Also there's no specs on stuff like sideloads or impact loading or anti-corrosion plating. I'm kinda mystified how this thing could work if cad plated without scraping off the cad plate, so ... Where I do see it making an impact, is "every gram counts" and if you took every washer and lockwasher off an instrument panel and replaced the nuts with these, you might save a small but measurable mass, which translates directly into a small but measurable increase in payload or range or lower fuel consumption or performance. Even on a small plane this might be a pound or two, but imagine a giant jetliner and it adds up to a respectable mass, probably financially a good idea... if its ever aerospace rated. Note that there's kind of big gap between being listed for sale on a foreign web page with no documentation at all and no specs or datasheets or certs, and being COTS at a place like "aircraft spruce and specialties". For laughs I went there and the price to beat for certified aerospace grade locknuts is like 48 cents a piece, so I donno if this new gadget can compete in the aerospace market at the typical 100x price markup... I mean sure saving weight and fuel is cool, but not if each aircraft certified nut costs $500.

JoeAltmaier 12y ago

Could be huge! Just the increased safety margins could be worth the cost - no lawsuits when a grinding head dismounts during operation due to loosening nut or whatever.

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.

jhallenworld 12y ago

Is it cheaper than loctite? A bolt with nut is supposed to work like a kind of high-tension spring pulling the pieces being fastened together. For large safety critical projects there is a technology to directly measure the tension of the bolt so that you know you have tightened the nut enough: http://www.checkline.com/product/TI-MINIMAX http://www.checkline.com/product/TI-MINIMAX This is better than a torque spec (where you don't know the friction exactly, so the bolt tension is an estimate).

eksith 12y ago
It may be better than adhesive when repeated removal is necessary. Thread locking fluid is a pain in smaller applications when the material flakes off as you untighten, which you have to clean up afterwards. In a clean-room or other delicate environment, having loose particulates is a big problem.
vonmoltke 12y ago
In a vibration-sensitive application, it may be needed in addition to a torque spec. The radar hardware I used to support had either Loctite or locking helicoils on nearly every mechanical attachment point. Our hardware would not have passed our vibe tests without it.

jhallenworld 12y ago

BTW, this "Eng-Tips Forums" is an excellent resource: http://www.eng-tips.com/threadminder.cfm?pid=725 http://www.eng-tips.com/threadminder.cfm?pid=725 (fun to read the nuclear engineering forum..)

lisper 12y ago

Is this actually any better than an ordinary nut with a teflon insert?

bronson 12y ago

I love the idea of a two part nut that cams itself tight. If weight and corrosion isn't a problem, this could see some good applications. Maybe locating on spinning shafts in high heat, or in blind holes? Stage 8 and safety wire seem simpler and they should offer more predictable torque for critical applications. Hoping to see some comparisons to existing solutions and failure analysis.

ha292 12y ago

Future YC startup: "XYZ is the self-tightening bolt to self-tightening nuts"

kazinator 12y ago

Those things look ridiculously well-made. Moreover, the thread is not simply cut in the nut, but rather a threaded insert is joined with the nut casing. That looks like it is more expensive to make, and could be an Achilles' heel if it is botched in production. Suppose a manufacturer cuts costs by using a cheaper metal for the casing, thinking only the threads have to be good quality; but then the nut is easy to strip. What if the two parts expand at different rates under heating. By the way, you can use two nuts to prevent loosening: http://en.wikipedia.org/wiki/Nut_%28hardware%29#Use_of_two_nuts_to_prevent_self-loosening http://en.wikipedia.org/wiki/Nut_%28hardware%29#Use_of_two_n... this could be cheaper than a much more expensive single nut. This article section explains how vibration causes loosening. The second nut ensures that the first nut stays in firm contact with the bolt threads even during moments when the pre-load is momentarily lost due to vibration, and so cannot rotate loose.

Scene_Cast2 12y ago

Saw this on diginfonews a while back, it's a neat concept. There's one thing that might be problematic with this design. The nut has a threaded c-shape insert. Due to the threading, when it is in the "wedged" position, it doesn't just have to close the gap between the tips of the "C" (let's suppose that this deformation is in the horizontal plane), it also has to deform vertically due to the threading. This vertical plus horizontal deformation must be either harsh on the material, require a relatively small amount of "wedge" (reducing the usefulness), or have a complex initial shape in anticipation of this type of deformation.