On Wednesday, February 4, 2015 at 4:07:33 AM UTC-8, dadiOH wrote:
wrote in message


... My aluminum miter gauge certainly scratches the top.

You have some remarkable aluminum (or wierd iron), aluminum is much softer
than iron. Here's a Moh's scale...

http://www.jewelrynotes.com/the-mohs...-is-important/

Anodized aluminum (aluminum oxide in a transparent form on the metal surface)
is also called corundum. Mohs scale, corundum is #9, and is quite a bit harder
than steel (4.5 or so).