Miller Electric OM-227 398D Owner's Manual page 34

Notes
MATERIAL THICKNESS REFERENCE CHART
24 Gauge (.025 in)
22 Gauge (.031 in)
20 Gauge (.037 in)
18 Gauge (.050 in)
16 Gauge (.063 in)
14 Gauge (.078 in)
1/8 in (.125 in)
3/16 in (.188 in)
1/4 in (.25 in)
5/16 in (.313 in)
3/8 in (.375 in)
1/2 in (.5 in)