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So I'm assembling a pull up bar and its assmebly instructions look like this

enter image description here

In the parts list it mentions only one type of spring washer (quantity 4).

But it actually came with two types of washers (quantity 4 each), type1 and type2.

Am I supposed to use both of them? And in what way? Any help would be appreciated!

  • 1
    Lock washers have been proven to not provide any benefit at all, it's amazing to me that they are still produced and used. NASA had this to say about them: “The typical helical spring washer … serves as a spring while the bolt is being tightened. However, the washer is normally flat by the time the bolt is fully torqued. At this time it is equivalent to a solid flat washer, and its locking ability is nonexistent. In summary, a lockwasher of this type is useless for locking.” – jesse_b Apr 2 at 17:44
  • @jesse_b A source (link) for this information would be nice to add, if possible. – Greg Nickoloff Apr 2 at 17:54
  • @GregNickoloff: here or here is a start but if you just google "Do lock washers work" you will find a ton of tests and data showing they do not. – jesse_b Apr 2 at 17:56
  • @jesse_b: I get it. But the thought is that someone already "googled" that to get here. For "completeness", etc. You quoted NASA so you should provide a link back to the source.... All good. – Greg Nickoloff Apr 2 at 18:12
  • @GregNickoloff I don't have a link handy, but I do recall reading in some NASA design standards that lock washers are explicitly disallowed. – Tristan Apr 2 at 18:37
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They gave you four lock washers instead of 4 locking nuts. No problem. Install the bolts as shown in the instructions. Then install a flat washer on each bolt followed by a lock washer and then the nut. Tighten as specified.

enter image description here

Picture Source

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  • Picture attribution link is supposed to be provided unless you happened to create that yourself. – Michael Karas Apr 1 at 21:14
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    @MichaelKaras Sorry about that. I thought the WikiHow in the lower right of the picture did that. – JACK Apr 1 at 22:24
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    On a tangent, a lock washer basically does nothing close to a lock nut. Do regular checks with this pull up bar, because your lock washers will loosen MUCH faster than a real lock nut. Replace with a real lock nut if you can; you don't want to break your neck over $10 worth of nuts. Info about lock washers – Nelson Apr 2 at 6:41
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    Or any second "jam" nut torqued into the first nut would lock it quite well also., – UuDdLrLrSs Apr 2 at 16:19
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    @DaMike The lock washers will be fine, I've used them in heavy machinery for 55 years and never had a problem. You will find them in probably every car built. Maybe NASA doesn't like them but you're not mounting your bar in the space shuttle. Looking at the position or your bolts if the nuts should ever loosen up you'll feel it long before they fall off. you should be doing regular checks on a bar like this anyway. – JACK Apr 2 at 22:57
7

Put the flat washer on first then the split lock washer and finally the nut.

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1

The advice from the German military shock testing establishment is to NEVER use any washer except a flat one.

It is the bolt that should be under tension and the bolt that provides the force that keeps the joint together. Spring washers, split washers and crinkle washers will eventually yield and the tension in the bolt will be lost. The joint WILL open up. At best the nut will fall off, at worst the bolt will experience shear or bending moments and fail.

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  • It would be good to have a source for this information if possible. – Greg Nickoloff Apr 2 at 17:52
  • That's very true for structural applications where the bolts are close to their capacity. However, for a pull-up bar even a single bolt with loose nut should be able to support the weight of a person. Though just to be safe, it's of course better to have a lock nut there. – jpa Apr 2 at 18:01
  • Some of the contents of your statement seems to be accurate but others don't make any sense. For example, bolts are often in shear, that's what they are designed to do, and that is completely separate from the nut or even how tight the bolt. – Ack Apr 2 at 18:21

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