I really don't know much about metals and what's typically available to machine. I saw the Kohler copper saddles and am intrigued by them and am thinking about doing a set of ABR-1 saddles in copper. The issue is, is I don't know what type of copper alloy to use. I know it's pretty soft. I know Be copper is hard but is there any other copper alloy (besides brass) that has a high percentage of copper but would be hard enough to use as a guitar saddle? Are the typical coppers offered by machine shops useable for guitar saddles?