# What do Washers Do? **URL:** \ **Category:** Factual Questions\ **Created:** [March 23, 2003, 12:13am UTC](https://boards.straightdope.com/t/what-do-washers-do/163454 "2003-03-23T00:13:55Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Torgo](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@Torgo](https://boards.straightdope.com/u/Torgo)\ **Post date:** [March 23, 2003, 12:13am UTC](https://boards.straightdope.com/t/what-do-washers-do/163454/1 "2003-03-23T00:13:55Z")
I recently assembled a large object in my basement and was pondering exactly what is the purpose of washers? The instructions called for pieces to be affixed with nuts and bolts, and sometimes with nuts, bolts and washers. Why were washers called for in some parts but not others? ---
**Author:** ![Davebear](https://avatars.discourse-cdn.com/v4/letter/d/bcef8e/32.png) [@Davebear](https://boards.straightdope.com/u/Davebear)\ **Post date:** [March 23, 2003, 12:20am UTC](https://boards.straightdope.com/t/what-do-washers-do/163454/2 "2003-03-23T00:20:10Z")
In some cases, they provide a sacrificial wear surface, so that the part they’re protecting doesn’t get worn; essentially acting as bearings. They are also used simply to provide extra thickness, so that a nut can be fully tightened. Or, to prevent the nut from slipping into or gouging the hole the bolt passes through. They also provide reinforcement of thin sheet metal. I’m assuming you are talking about flat steel washers, not lock or rubber washers. ---
**Author:** ![hammerbach](https://avatars.discourse-cdn.com/v4/letter/h/73ab20/32.png) [@hammerbach](https://boards.straightdope.com/u/hammerbach)\ **Post date:** [March 23, 2003, 1:00am UTC](https://boards.straightdope.com/t/what-do-washers-do/163454/3 "2003-03-23T01:00:07Z")
They also spread the fastener load over a larger area. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 23, 2003, 1:02am UTC](https://boards.straightdope.com/t/what-do-washers-do/163454/4 "2003-03-23T01:02:39Z")
[related hijack] Anyone know why they are called washers? [/related hijack] ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [March 23, 2003, 1:37am UTC](https://boards.straightdope.com/t/what-do-washers-do/163454/5 "2003-03-23T01:37:33Z")
> [@](#): > > \*Originally posted by Q.E.D. \* > \*\*[related hijack] > > Anyone know why they are called washers? > > [/related hijack] \*\* [Etymology online sez](http://www.etymonline.com/w1etym.htm) > [@](#): > > Washer “flat ring for sealing joints or holding nuts” is attested from 1346, but the connection is unaccounted for, and it may derive from the ancestor of Fr. vis “screw, vise.” [other sources](http://www.wordwizard.com/clubhouse/founddiscuss.asp?Num=3945) > [@](#): > > WASHER noun [origin unknown] Middle English [from the word ‘wash’ + ‘- er’] A perforated annular disc or flattened ring of metal, leather, etc. placed between two rotating surfaces to relieve friction and prevent lateral movement. (New Shorter Oxford English Dictionary) > > WASHER noun: Development of the meaning of a flat ring for sealing joints or holding nuts . . . [[~1350]]. . has not been accounted for. (Barnhart Concise Dictionary of Etymology) > > WASHER noun: [14th century] small disk with a hole. Is usually assumed to come from the same source [[as the word ‘wash,’ as in ‘to wash with water’]], but its semantic link has never bee satisfactorily explained. (Ayto’s ‘Dictionary of Word Origins’) ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 23, 2003, 1:40am UTC](https://boards.straightdope.com/t/what-do-washers-do/163454/6 "2003-03-23T01:40:42Z")
So nobody knows, then. Where’s Cecil when you need the really tough questions answered? ---
**Author:** ![herman\_and\_bill](https://avatars.discourse-cdn.com/v4/letter/h/f1d935/32.png) [@herman\_and\_bill](https://boards.straightdope.com/u/herman_and_bill)\ **Post date:** [March 23, 2003, 1:05pm UTC](https://boards.straightdope.com/t/what-do-washers-do/163454/7 "2003-03-23T13:05:32Z")
They provide a larger bearing surface so the fastner can be tightened more than with out one split washers and star shaped washers are to prevent the fastener from working loose