On Fri, Jan 10, 2014 at 5:58 PM, Michael Ross <[email protected]>wrote:
> Yes Evan, you have it exactly right. The popularity of lock washers is > without merit. I will give you a caveat though, I am talking about joints > where there is all metal in the sandwich. More detail below on > non-metallic stuff. > > I believe you are wrong about the Toyotas at leas with all metal joints. > Tie rod ends are not castellated on my car, they are big and torqued hard > with a tapered fit that really does the work. There is no thread locker > that I have seen, and no nylocks. If you show me I will believe, but I do > my own wrenching and have not seen any. I have seen some deformed nuts > where they whack the end of the nut into an ellipse for use on exhaust > stuff that has extreme thermal cycling). There are things like battery > hold downs - not an all metal joint, but I am pretty sure even these are > not nylock or deformed. > I've never owned a Toyota but I am surprised about that. Certainly every other car make I've ever worked on, it holds true. > You are right to press me on this - Why on earth are there all these lock > washers used? Why do so many people think they are useful? Heck, Nordlock > may be quite sincere in thinking their fancy washers do something. Part of > this is tradition that is self sustaining - they are everywhere so the must > be good, right? Also, lock washers do get applied places where, > unfortunately they help, because of design flaws (usually material > selection). In every case they are a bandaid for a joint that could have > been better, but maybe cost too much better, or there wasn't time to do > better, and besides, everyone uses them, right? > You're right, no design sets out to intentionally require lock washers, but y'know, stuff happens. It's not a perfect world and sometimes other factors such as cost or weight have a higher priority - you can call this bad design if you like but it seems a bit pedantic. So yes, they're a bandaid, but they do serve a purpose. I've worked on heavy equipment in the past (including Cat / Timberjack stuff) and I can tell you that if they don't come from the factory with Nord-Locks on certain cover plates and the like, they certainly end up that way after it all rattles loose after a few hours in service. > That does not change the fact that a split lock washer, or a Nordlock is a > waste of money in a joint that is tight enough not to come loose. And you > can design or modify joints so they don't come loose. > Yes you can, but it's far easier and cheaper to add a lock washer or spring washer than go back to the drawing board. Are you really going to be able to re-engineer a Chinese lithium cell so that it no longer has a critical joint made of two soft metals secured with a single small bolt, threaded into aluminium? Having given it further thought, slackening of the joint is likely to be the concern in this application rather than spontaneous loosening (in most car applications, I don't think there's enough or the right sort of vibration to cause the bolt to undo). And the spring washer is there to deal with the slackening. Leaving it out or changing to a lock-washer (or thread-lock) alone is asking for trouble IMHO. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140113/43973074/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)
