AMS-6345, Mil-S-18729

Alloy Temper Size and Thickness
4130   1 × 4 × 0.040
4130   1 × 6 × 0.040
4130   2 × 3 × 0.040
4130   2 × 4 × 0.040
4130   3 × 4 × 0.125
4130   4 × 4 × 0.040 / Hole
4130   3 × 6 × 0.040
4130   4 × 6 × 0.040
4130   3 × 10 × 0.040