Don't ask me, ask Nord-Lock ;) http://www.youtube.com/watch?v=mgwmuZuJ02I
On Thu, Jan 9, 2014 at 5:38 PM, Martin WINLOW <[email protected]> wrote: > A-ha! I had not seen them 'in the flesh' as it were, before. So, what's > the difference between using them and a serrated washer, then? I > appreciate the two halves have to move apart to twist relative to each > other - and therefore make the bolt stretch etc - but what's to stop the > serrations just cutting off some of the bolt head or whatever and, in > effect, by-passing the Nord-Locks? If you could get Nord-Lock-like > castellated cell interconnects and matching bolt head bottoms then I could > see you would definitely be on to a winner but as it stands I still don't > see what you are gaining by using a Nord-Lock washer. > > MW > > > On 9 Jan 2014, at 17:06, Evan Tuer wrote: > > > They are serrated on the outer faces of the pair Martin, so grip the bolt > > head and whatever you're bolting too very effectively. When you try to > > undo a bolt like this, the cam action of the inner faces forces them > apart, > > making them grip even tighter. > > Nord-Locks are great, but overkill for battery terminals I would have > > thought. > > > > IMO the concern for our application is relative movement between cells > > causing the rigid straps to "turn" fractionally, with a low frequency. > > With a plain washer alone, I could imagine that eventually slackening off > > the bolt. Maybe the spring washer is doing something useful, as it will > > have a sort of ratchet action, preferring to tighten the bolt rather than > > loosen it. > > > > > > > > > > > > On Thu, Jan 9, 2014 at 4:49 PM, Martin WINLOW <[email protected]> wrote: > > > >> I have a concern over Nord-Lock (NL) washers. It is simply that there > is > >> - as I understand it - a plain metal to metal interface between the top > of > >> the NL washer and the underside of the bolt head. Then there is another > >> plain interface between the bottom of the NL washer and the article that > >> the bolt is securing. Whilst I can see that there is an interesting > and no > >> doubt effective mechanism to resist movement between the 2 halves of > the NL > >> washer, what is stopping the bolt head moving relative to the top half > of > >> the NL washer or the bottom half of the NL washer relative to the > 'secured > >> article'? > >> > >> They just seem to be moving the slipping point, or rather they are not > >> because these two regions is where slipping would occur with just a > >> standard washer in there instead of a NL one. So I'm not convinced. MW > >> > >> > >> On 8 Jan 2014, at 04:24, David Nelson wrote: > >> > >>> How was the Nord lock video rigged? Have you used nord-lock washers? > >>> > >>> "The vibration that a dozer undergoes traversing rock, day in and night > >>> out, is incredible." > >>> > >>> There is no doubt about that. However, the tension in the bolts in one > is > >>> also significantly higher than what an M8 bolt is under when in an > >> aluminum > >>> post. Scale does affect how things behave. > >>> > >>> What is your experience with prismatic batteries like the TS or CALB > >> cells > >>> that many of us are using? Is your pack put together with no terminal > >> prep > >>> and no washers? What is your climate like? > >>> > >>> On Tue, Jan 7, 2014 at 6:55 PM, Michael Ross <[email protected] > >>> wrote: > >>> > >>>> I guess I am old school. I did mechanical design at Caterpillar for 4 > >>>> years and have a copy of their tome on bolted joint design. I have > seen > >>>> their labs and proving grounds. They build front shovels that weigh > 1.5 > >>>> MILLION lbs, seriously. The down time on these things is incredible > and > >>>> they spare nothing to be convinced of the components and procedures > they > >>>> use. The vibration that a dozer undergoes traversing rock, day in and > >>>> night out, is incredible. > >>>> > >>>> I think Nordlock is snake oil in comparison. But that is me. YMMV, > but > >> I > >>>> bet less. > >>>> > >>>> > >>>> On Tue, Jan 7, 2014 at 8:21 PM, David Nelson <[email protected]> > wrote: > >>>> > >>>>> On Tue, Jan 7, 2014 at 3:55 PM, Michael Ross < > [email protected] > >>> > >>>>> wrote: > >>>>>> Hi Jukka, > >>>>>> > >>>>>> Is that "tight enough" ± a smidge? I am going with the torque > wrench. > >>>>>> > >>>>>> I watched a class once where people tried to control applied torque > by > >>>>> feel > >>>>>> with the max hold set, but hidden, then check the max after to see > how > >>>>> well > >>>>>> that worked. It was just terrible. A person might get it right > once, > >>>>> but > >>>>>> they were unable to do very well repeatedly. > >>>>>> > >>>>>> Then a set of seemingly identical joints were torqued, and the > >>>>> un-torquing > >>>>>> checked. Again, no correlation to the applied torque. > >>>>> > >>>>> I'm wondering if they did a controlled test to see how well a > "machine" > >>>>> did. > >>>>> > >>>>>> My contention is this loosening is not because the joints are prone > to > >>>>>> loosening, but that they were not torqued correctly to begin with, > and > >>>>>> maybe sometimes not enough. If you torque them right, they won't > >>>> loosen > >>>>> - > >>>>>> ever. > >>>>>> > >>>>>> Mike > >>>>> > >>>>> I'm not quite buying your last line there. With no movement then yes > >>>>> but with vibrations in all directions, no. I've seen this test in > >>>>> other videos but couldn't find them but here is one to show what > >>>>> happens with a bolt/nut and a vibrating machine with strain gauge: > >>>>> http://www.nord-lock.com/wp-content/uploads/2012/06/nl_us.wmv > >>>>> _______________________________________________ > >>>>> 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/20140107/6514640c/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) > >>>> > >>>> > >>> > >>> > >>> -- > >>> David D. Nelson > >>> http://evalbum.com/1328 > >>> http://www.levforum.com > >>> -------------- next part -------------- > >>> An HTML attachment was scrubbed... > >>> URL: < > >> > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140107/6d7f829e/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) > >>> > >> > >> _______________________________________________ > >> 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) > >> > >> > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140109/e57eb1db/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) > > > > _______________________________________________ > 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) > > -------------- next part -------------- An HTML attachment was scrubbed... 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