<http://schema.org/description>
"&lt;p&gt;As tolerances for machined holes keep getting tighter, we are learning that no hole possesses a geometrically perfect, symmetrically round shape.  No hole is likely to take on a perfect oval (two-lobed) form, either. &lt;/p&gt;"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mmsonline.com/columns/gaging-diameter-variation-in-machined-holes>