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 <m...@winlow.co.uk> 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 <michael.e.r...@gmail.com >>> 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 <gizm...@gmail.com> wrote: >>>> >>>>> On Tue, Jan 7, 2014 at 3:55 PM, Michael Ross <michael.e.r...@gmail.com >>> >>>>> 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 >>>> >>>> michael.e.r...@gmail.com >>>> <michael.e.r...@gmail.com> >>>> -------------- 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)
