Evan, There is no relation between the graphs and the video. The video shows a joint that is not tight. It is just eye candy. Anyone can draw a graph. They have not connected the dots.
Lets work backwards. Maybe I will see my error. We have a tight joint: There is a block with a hole in it. It is sitting on another block, and a pin is sticking up through the hole from the lower block. The pin has a broad shoulder the covers the hole, plus some. If the pin is too short for the hole, and it is stretched so the shoulder bears down on the upper block, then the spring force of the stretched pin is pushing the top block onto the lower. If the pin is short enough, the force is very high, and the two blocks won't move relative to each other. What can cause this to fail? The block has to shrink. the pin has to stretch, or the side forces have to grow considerably Nothing else will do it. If the top block compresses - a design issue - a stronger material was needed. If the pin is big enough it won't have experienced plastic deformation and failed - a design issue - use big enough pins. If the side forces grow - a design issue - do your home work better and spec enough clamping force to withstand the side forces. You can hypothesize about thermal effects and different materials with different coefficients of thermal expansion, but this too is predictable and solves by a higher clamping force. If you start to look at this where the pin is now a threaded bolt in a threaded hole, then there is an added failure mode where the bolt spins. But what causes that? If there is no motion in the joint, so there is no spinning of the bolt. You have to have one of the first three failures to get the bolt to spin. What failure mode can we come up with that isn't solved by more clamping force and a proper bolt, with enough thread engagement to take the forces? None of these requires resorting to a fancy weird washer to solve the problem. The lock washer can't possibly do anything as long as the joint is tight. Please explain what I got wrong here. Now, if using a Nordlock gets people to read the torque specs, buy a torque wrench, and use it to tighten even more than without, yes, it will be effective. On Thu, Jan 9, 2014 at 2:53 PM, Evan Tuer <[email protected]> wrote: > On Thu, Jan 9, 2014 at 7:37 PM, Michael Ross <[email protected] > >wrote: > > The video made me even more wary, because they purposely left that joint > > they vibrated loose, to exaggerate the effect. > > > > > If you look at the graphs, they all started off at the about same bolt > tension, so it is a fair test. > > > > > The business comparing the angles of the Nordlock and the threads eluded > > me. And watching the ramps ride up and pop down was troubling. All > those > > serrations top and bottom. Why do I like that? > > > > This all seems so unnecessary. I really don't get it. > > > > > It's pretty simple: turn a bolt anti-clockwise and it loosens off, > according to the pitch of the thread. The ramp on the Nord-Lock cam is > steeper than the thread pitch, so it acts to increase the bolt tension and > thus the thread friction as soon as it tries to move. > > I've used them, they're very effective in situations where you don't want > to use Loctite. If you don't believe it, try it yourself! I see no need > to use them for batteries though, or for anything else on an ordinary car. > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140109/309276ac/attachment.htm > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." To invent, you need a good imagination and a pile of junk. Thomas A. Edison<http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140109/6589facb/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
