10 mil steel was well & truly worthless in the toe plug.

The decision was made to introduce the 1st titanium sample in the toe plug.

It was  12 mil, 6Al, 4V.  Much harder to drill than steel & the grinder couldn't expand the hole, but the drill didn't shred it & the grinder managed to grind off the burrs.

12 miles later, it was about as pulverized as plastic.  Suspect 20 mil will be more effective than any other material, but nothing will be indestructible.  The mane source of titanium for consumers is titaniumjoe.com.  

The farstener situation was the mane issue with the heel, so adhesives showed the most promise.  

Loctite metal on metal ground with the grinding wheel showed the best results.  

It was actually stronger than the hot glue which served for hundreds of miles.  It can be applied after the laces & built into a spacer.  The mane problem is the 12 hour cure time.