View source for O-ring

[[Image:O-rings.jpg|frame|Some small o-rings]]An '''o-ring''' is a rubber gasket with a round cross-section, and is usually used to create an airtight seal around moving parts, such as pistons and bolts. O-rings are cheap and come in a wide range of sizes. However they need to be mounted in a precisely machined groove for most applications, and a [[lathe]] is usually needed to achieve this, so they are not always a viable option. 

An o-ring seal, when done correctly, can hold thousands of [[psi]].

For those with a lathe, the process for machining an O-ring groove is:
<ol><li>Chuck the workpiece well, ensuring that it rotates true.
<li>Gently measure the actual radial thickness of the O-ring.
<li>Using a cut-off tool or similar tooling that will produce a deep flat bottomed cut, cut a groove of the proper width to a depth that will put a 5-10% squeeze on the O-ring. 
</ol>
This depth can determined by the formula O*(100%-S%) - 1/2(OD - ID) Where O is O-ring thickness, S% is the percent of squeeze (higher percents make tighter O-ring seals), OD is the outside diameter of the interior part, and ID is the inside diameter of the exterior sleeve.

Putting the O-ring on the exterior sleeve is not recommended, as it is harder to machine and tends to fall out if the interior part fails to press against it.

==External links==
[http://www.oringsusa.com/ much info on 'rings]
[[category:construction materials]]


{{stub}}