Colbalt probably wont do too well, carbide to get through the hardened outer surface.

Originally Posted By 440dart
Cobalt from Grainger item# 1G865

1941 Taylorcraft
1968 Charger
1994 Wrangler
1998 Wrangler
2008 Kia Rio
2017 Jetta

I didn't do 4 years and 9 months of Graduate School to be called Mister!