I get my machine shop supplies online from Victor. Dykem makes a version of Prussian Blue called "hi-spot blue". It's the grease-based paste which doesn't dry quickly.

http://www.victornet.com/alphabetic/Blue-Layout-Fluid/329.html

Bottom of the page- - - -you'd need to order a few more items to get up to Victor's minimum order, however. They're very reasonable on prices for drill bits, cutting tools, and precision measuring tools like dial calipers, micrometers, etc.
Jerry

Last edited by Hotrod Lincoln; 10/13/2012 10:15 AM.
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