Page 1 of 2 12 LastLast
Results 1 to 15 of 17
  1. #1
    Join Date
    May 2020
    Location
    Willowbank QLD
    Posts
    518

    Default Please school me on lock washers

    Hello all

    I know this is not strictly metal work but many of our projects are held together by fasteners.
    I have heard many conflicting stories on the advantage, or disadvantage of lock washers.
    Therefore I am calling on all closet fastener engineers to share their knowledge.
    There are many different varieties such as star, split, nord, and the list goes on.

    The project I am working on is automotive and subject to vibration.
    Please discuss, I will be keen to learn what I can.

    Thanks Steve

  2. #2
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,944

    Default

    Hi Steve, as there are many different applications of lock washers, if we knew what the intended situation was, either a description or a pic, it would be an easier recommendation. i.e. for tail shafts, I would use tab washers, possibly the same for front end overhauls. 4WD's use tab washers also to lock the 2 nuts together, the washer having an internal lug which locates in the stub axle, and 2 tabs on the outside to lock onto the inner and outer nuts.
    Spring washers would be for general antivibrations as they are a cheaply manufactured item.
    Star washers can also be used in a similar situation, but are more expensive to make.
    If it was really vibrating, you could use a castellated nut and slit pin.
    https://www.globalspec.com/learnmore...teners/washers
    Here's a link to Tab washers
    https://www.google.com/search?q=tab+...V_enAU748AU748
    Hope this helps a bit.
    Kryn
    To grow old is mandatory, growing up is optional.

  3. #3
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
    Posts
    2,651

    Default

    Sounds like you might be wanting to know about fastener locking in general rather than just lock washers.

    Here’s a few snippets from my knowledge/experience.

    Locknuts (there are different sorts) can be used in place of standard nuts and lock washers.

    Spring washers can lose their hardness and spring when used on high temperature components like exhaust manifolds and turbo housings.

    Standard spring washers bite into the material they are fastening to and aren’t a good choice on soft materials when they are being removed frequently as they can cause quit a bit of damage. Likewise on thin materials. They can also initiate cracks on highly stressed components.

    Nylok nuts aren’t any effective at temperatures above about 120degC

    Steve

  4. #4
    Join Date
    Jun 2005
    Location
    Helensburgh
    Posts
    618

    Default

    Spring washers were always the go to answer and star washers were primarily used to ensure a good electrical connection on terminals. I raced karts for many years and nothing cops a bigger hiding from vibration than every single faster on a kart. Nylocks are the default fastener with no washer and as long as they were regarded as one use only they never failed. They can be bought with a seating flange in the nut as well where that is useful. The big thing using nylocks is there must be at least 1.5 threads protruding after tightening the nut. High temperature applications usually use tabs or similar to to stop fasteners releasing.
    CHRIS

  5. #5
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,541

    Default

    Recently I have been watching a Youtube channel (KSR fabrications) where the guy builds race cars (track and drag). He uses Nordlock washers (and has for some years) on his joints.

    The whole idea behind threaded fasteners is that the fastener is tightened up to such an amount that the shaft of the fastener stretches (elastically)*. A very stiff spring if you like. The theoretical state is that the fastener is just pulling the two items being joined together so that friction between the surfaces keeps the part together. A plain washer is there to spread the clamping force a little and help the fastener tighten without chewing into the substrate. Some flat washers have a tab or other means on them to lock them to the nut, in theory stopping it undoing.
    A locking washer does the load spreading thing but also acts as a secondary spring to keep force between the nut and the fastener, lessening the ability of the nut to just shake loose.

    I don't like the classic split washer; to me it seems to only be applying force to one point on the nut. Tabbed washers do work but need to be properly set up as locking the washer to a nut (or bolt head) just means that both shake loose together. Serrated washers are normally not used for any vibration purposes and are more likely to be used for electrical conductivity - cutting through paint/ oxide to make sure an electrical conductor is getting to raw metal. Nords I like, but most of the time I will use nylocs or loctite. As Chris says, nylocs are typically a one-time use nut. They are used on aircraft on that basis. Typically though for critical fasteners on equipment subject to lots of vibration (aircraft, tracked vehicles), a physical restraint such as wire-locking is used to make sure nothing comes loose. Castelated nuts with split pins are another way of doing this and are (were?) common technology on critical automotive joints (steering for example).

    Not too long winded I hope.
    Michael

    *vibration can make the tension in the bold oscillate around that mean value - if it gets down enough, the bolt can loosen.
    Last edited by Michael G; 4th Apr 2021 at 09:31 AM. Reason: added a bit

  6. #6
    Join Date
    May 2020
    Location
    Willowbank QLD
    Posts
    518

    Default

    Thanks for the replies so far. The project is an Indian motorcycle. I had an old Triumph that used to shed parts at a regular rate. I was a lot younger and it may have been incorrect application of fasteners or torque.

    I have read a few articles that claim the humble split washer is actually worse than no washer at all. I have also read that Elvis is working at 7/11 stores so you can't believe everything you read.

    Essentially this question was designed to expand my knowledge and allow me to make an educated decision when selecting appropriate fasteners and locking devices.

    Thanks

    Steve

  7. #7
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

    Default

    Have a read of Carrol Smiths book, Nuts Bolts Fasteners and Plumbing handbook. Likely you’ll never use a spring washer again after you do.

  8. #8
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    67
    Posts
    362

    Default

    Quote Originally Posted by racingtadpole View Post
    Likely you’ll never use a spring washer again after you do.
    I cannot remember the last time I used a spring washer. Flat washers and a nylock nut.


    Tony

  9. #9
    Join Date
    Oct 2008
    Location
    N.W.Tasmania
    Posts
    1,407

    Default

    I realise that most won't need the extreme performance that these Huck bolt deliver, there are times when they can really save the day. At the mine and concentrating mill I worked at for nearly 18 years, there were times when ordinary high tensile bolts were not good enough. As has already been mentioned spring washers are a dead loss in high vibration scenarios, they simply break and fall out leaving the thickness of the spring washer slop in the bolt, so the whole lot fall in the hole. There were three applications which stick in my mind where huck bolts held for years in some cases, where conventional bolts would fail in weeks or sometimes just days. The drive head of rock drilling machines which bored in our case 9" diameter holes in hard rock for blasting purposes had severe vibration during operation, and even using fitted bolts in reamed holes was no match for the conditions. Another case was the vibrators on the vibrating screens in the concentrating mill. These screens weighed about 7 tonnes and had 2 electrically driven vibrating units fitted to an inverted U shaped framework of IIRC cast steel about 35mm thick, with quite a few bolts holding both the vibrators to the frame and the frame to the vibrating screen housing, and replacing loose bolts on shutdowns was a regular pastime. The final example which comes to mind was a Caterpillar D8 which had track drive sprocket segments which kept coming loose. This would have been caused by lack of timely maintenance in tightening these bolts on service days. After a time a loose bolt would flog out the holes in the segments and or the carrier hub to which the segments were bolted. They did not have to wear much, as I recall the wear was nearly un-noticable to the naked eye, unless you dropped a new sprocket segment bolt in perhaps, and instead of being a really neat fit, it would be a slip fit, but that was all it took to make the bolts impossible to keep tight.To fix it using genuine Caterpillar parts would have meant replacing the carrier and all the sprocket segments and using all new bolts as well. That would be an expensive undertaking in both time and parts, especially as the parts were relatively new and would have many hundreds of hour life left if we could keep the fasteners tight.
    The solution was to use Huck fasteners, which are more of a rivet than a bolt because what appears to be a thread, is really just a series of parallel thread like grooves around the shank, and instead of a nut, they have a collar which is squeezed tight onto the shank, and in my experience, the only way to get one off was to cut it off, usually with oxy. They come in a few different flavours, the ones we used had a shear point machined into the shank and broke when the hydraulic pressure had squeezed the collar to final end point locking everything together. They were very impressive.https://www.youtube.com/watch?v=La1uQ5t08I0 The YouTube vid gives the general picture of how they work.

  10. #10
    Join Date
    May 2020
    Location
    Willowbank QLD
    Posts
    518

    Default

    Thanks for the really interesting reply. I may have to look into some of the larger ones when I come to replace some rivets in a 1941 Chev truck chassis.

    Steve

  11. #11
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

    Default

    Locally sourced tooling for Huck Bolts starts at over $1200 (if by larger you are talking 3/8 diameter, the tooling is just shy of $6k locally sourced). The bolts themselves are cheap enough, 50 3/16 shanks with a 1.6 to 15mm grip range and collars is just over $20.
    Youll also need to look into it with your local Road Transport authority, they are not approved for road going chassis repair in every state, most states specify use of Grade 8 or 8.8 threaded fasteners for chassis use on a road registered vehicle.

  12. #12
    Join Date
    Oct 2008
    Location
    N.W.Tasmania
    Posts
    1,407

    Default

    Quote Originally Posted by racingtadpole View Post
    Locally sourced tooling for Huck Bolts starts at over $1200 (if by larger you are talking 3/8 diameter, the tooling is just shy of $6k locally sourced). The bolts themselves are cheap enough, 50 3/16 shanks with a 1.6 to 15mm grip range and collars is just over $20.
    Youll also need to look into it with your local Road Transport authority, they are not approved for road going chassis repair in every state, most states specify use of Grade 8 or 8.8 threaded fasteners for chassis use on a road registered vehicle.
    I think that you may be able to hire the tooling, if you only had a short term single use need, but am not certain of that. U.S. eBay would also be worth looking at at those prices. From memory the Huck Fasteners that we most often used were 5/8 or 3/4", but the sprocket segment bolts would I think have been more like 7/8" Cat bolts, most likely way better than grade 8, more like 10 or 12, but while we could not make them work for long on the worn carrier, Huck bolts lasted until the sprocket segments had worn out, and then the whole assembly was replaced with new parts. I don't ever recall Huck bolts failing, they were so good. In some ways I am not surprised that the RTA in some states will not approve Huck bolts, but insist on threaded grade 8 or 8.8 fasteners, because they do have some strange rules which I can't see the logic in. One example is the requirement for "Trailer Chain" for light trailers or caravans etc under I think 4.5 Tonnes. The trailer chain has to be of the appropriate spec, which I am unable to quote for now, but it is not legal to use Herc Alloy lifting chain for these trailers, but for trailers over 4.5 tonnes that is what you have to use. Go Figure! I am not saying that grade 8 or 8.8 for metric fasteners will not do the job on a road going chassis, but if they will do the job, Huck Bolts will do it even better in my experience, so why would you rule them out. Unfortunately sometimes bureuracracy runs to their own rules, and often a single individual abuses the powers given to them, or has a set against something or someone for no logical reason what so ever.

  13. #13
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,541

    Default

    Quote Originally Posted by Ropetangler View Post
    ...Unfortunately sometimes bureuracracy runs to their own rules, and often a single individual abuses the powers given to them, or has a set against something or someone for no logical reason what so ever.
    It is more likely to be money - that is, who is going to pay for their time to examine these things. We get stuff approved at work for electrical installations, and invariably there is a fee for any approval we wish to have done, after we have submitted all the paperwork. These days unless someone requests approval and pays for a public servant to look at it, it is unlikely to happen.

    Michael

  14. #14
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

    Default

    For funsies I had a look at second hand tooling through eBay, that brings the cost of the pneumatic over hydraulic set used for the larger ones down to about USD 1300. The plain pneumatic tool used for the smaller ones is cheaper to buy a new one locally, they are around the USD 1000 Mark.

    The reason they specify bolts has more to do with safe installation, literally anyone can put a nut and bolt in and tighten it to a specified torque. Not everyone can successfully apply specialty fasteners such as Huck bolts or Mono bolts. If I were doing a chassis repair, I’d be getting all Pakistani Truck (check out the YouTube channel, it’s quite interesting to see how things get done with a full equipped western style workshop) on it and doing direct replacement of the rivets with new heat set solid rivets. It looks period correct, the local road transport constabulary will never be able to tell the difference and be equivalent to OEM if done correctly (refer previous comments on why bolts are usually spec’d).

    The reason you can’t use Herc Alloy on light trailers is because it’s permissible to weld the chain on a light trailer, on a heavy trailer it needs to be bolted in a double shear fashion. You can use Herc Alloy on a light trailer but it must be in the same double shear configuration. No trailer manufacturer is ever going to do that when welding a piece of Galv fence chain is available as an option. And most home gamers that build trailers don’t know what a double shear plate assembly looks like let alone have the ability to successfully construct one for a safety application, so again it comes down to the lowest common denominator being catered for.

    So now the thread is well and truly hijacked, my work here is done

  15. #15
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,944

    Default

    The reason you can’t use Herc Alloy on light trailers is because it’s permissible to weld the chain on a light trailer, on a heavy trailer it needs to be bolted in a double shear fashion. You can use Herc Alloy on a light trailer but it must be in the same double shear configuration. No trailer manufacturer is ever going to do that when welding a piece of Galv fence chain is available as an option. And most home gamers that build trailers don’t know what a double shear plate assembly looks like let alone have the ability to successfully construct one for a safety application, so again it comes down to the lowest common denominator being catered for.
    In case anyone is interested, these are what we use to mount safety chains onto the majority of our trailers.
    safety chain connector.jpg
    To grow old is mandatory, growing up is optional.

Page 1 of 2 12 LastLast

Similar Threads

  1. Does anyone know where to get small crenellated S/S washers?
    By Grahame Collins in forum METALWORK GENERAL
    Replies: 6
    Last Post: 13th Aug 2018, 10:07 PM
  2. Do Rubber Washers Decay?
    By bayviewboom in forum METALWORK GENERAL
    Replies: 4
    Last Post: 29th Jul 2017, 03:24 PM
  3. Replies: 26
    Last Post: 20th Apr 2016, 11:49 AM
  4. Chinese Black Nuts, Bolts & Washers
    By Jim Ferrous in forum METALWORK GENERAL
    Replies: 11
    Last Post: 31st Oct 2013, 08:59 PM
  5. Correct placement of split/spring washers
    By BenM78 in forum METALWORK GENERAL
    Replies: 16
    Last Post: 17th Dec 2010, 06:50 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •