Weird hex size

Hello. I have M3-threaded hex spacers with about 4.53 mm across flats. What could be the nominal size be ? It's way too small to
be 5 mm, probably too big to be 4.5 mm and it's 5% away from 3/16" (~4.76 mm) which looks at bit too sloppy to be true.
--
Andr้ Majorel <URL:http://www.teaser.fr/~amajorel/
"Marque nouvelle. Dans le stock. Les navires de FL, les
  Click to see the full signature.
Add pictures here
โœ–
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Andre Majorel wrote:

Whitworth?
Add pictures here
โœ–
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 3 Jan 2010 09:39:05 +0000 (UTC), the infamous Andre Majorel

Oh, shucks! When I read the subject line, I thought this was going to be a nice witchy thread starting up. Darn.
-- Society is produced by our wants and government by our wickedness. --Thomas Paine
Add pictures here
โœ–
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I'd call it at 4.5 mm.. The difference of .03 mm is equivalent to . 00118", well within 'normal' manufacturing tolerance and certainly a 4.5mm open end wrench [if there is such a beast] would fit.. For sure a 'universal metric fitzall' AKA 4" crescent wrench would work fine.. ;-)

Add pictures here
โœ–
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.