Machinist Conversion Chart
Interval Settings
in
in
= 0.015625 in
Gauge Systems
Data Sources: Letter and number drill decimal sizes are read from ASME B94.11M-1993 ("Twist Drills"),
Table 1 — verified directly against the standard's own table, not a secondary reference.
Gauge numbering (Steel, Galvanized Steel, Stainless Steel, Aluminum, Zinc, AWG) is not an ASME or ISO standard — ASTM explicitly discourages its use ("an archaic term of limited usefulness not having general agreement on meaning," ASTM A480/A480M) — and neither ASME nor ISO publishes a gauge-number table. These values are Machinery's Handbook (Oberg) figures, read from the raw source tables directly rather than a paraphrased summary. The one exception with real legal weight is US Standard Gauge, which is defined by U.S. federal statute, 15 U.S.C. § 206. Aluminum sheet and AWG wire share the same Brown & Sharpe (B&S) numbering, listed as separate systems here since they're commonly looked up separately.
Gauge numbering (Steel, Galvanized Steel, Stainless Steel, Aluminum, Zinc, AWG) is not an ASME or ISO standard — ASTM explicitly discourages its use ("an archaic term of limited usefulness not having general agreement on meaning," ASTM A480/A480M) — and neither ASME nor ISO publishes a gauge-number table. These values are Machinery's Handbook (Oberg) figures, read from the raw source tables directly rather than a paraphrased summary. The one exception with real legal weight is US Standard Gauge, which is defined by U.S. federal statute, 15 U.S.C. § 206. Aluminum sheet and AWG wire share the same Brown & Sharpe (B&S) numbering, listed as separate systems here since they're commonly looked up separately.