Machinist's Pocket Card — Drills, Gauges, Hardness & Densities

One-page machinist's card: number and letter drill sizes, sheet metal gauges, HRC hardness conversions, and metal densities.

Updated August 20, 2026

The bench lookups a machinist makes between print and part, on one card: decimal equivalents for the number and letter gauge drills of ANSI/ASME B94.11M, sheet metal thickness by gauge for steel, stainless, and aluminum, the ASTM E140 steel hardness ladder from HRC to Brinell and Vickers with approximate tensile strength, and datasheet-verified densities for the common shop alloys.

Every cell is generated from the constants behind the tap drill, metal weight, sheet metal gauge, and hardness conversion pages — pound-per-cubic-inch densities are computed from the exported kg/m³ with exact unit factors, never retyped. Print it for the toolbox lid; the linked pages carry the full tables this card trims.

Machinist's Pocket Card — Drills, Gauges, Hardness & Densities — updated August 20, 2026

Number & letter drills (ANSI B94.11M)

DrillinDrillinDrillin
#400.0980#390.0995#380.1015
#370.1040#360.1065#350.1100
#340.1110#330.1130#320.1160
#310.1200#300.1285#290.1360
#280.1405#270.1440#260.1470
#250.1495#240.1520#230.1540
#220.1570#210.1590#200.1610
#190.1660#180.1695#170.1730
#160.1770#150.1800#140.1820
#130.1850#120.1890#110.1910
#100.1935#90.1960#80.1990
#70.2010#60.2040#50.2055
#40.2090#30.2130#20.2210
#10.2280A0.2340B0.2380
C0.2420D0.2460E0.2500
F0.2570G0.2610H0.2660
I0.2720J0.2770K0.2810
L0.2900M0.2950N0.3020
O0.3160P0.3230Q0.3320
R0.3390S0.3480T0.3580
U0.3680V0.3770W0.3860
X0.3970Y0.4040Z0.4130

Decimal inches, ascending: #40–#1 then A–Z. #80–#41, fractional, and metric sizes: drill bit sizes chart.

Sheet metal gauges (in)

GaSteelStainlessAluminum
70.17930.18750.1443
80.16440.17190.1285
90.14950.15630.1144
100.13450.14060.1019
110.11960.12500.0907
120.10460.10940.0808
130.08970.09380.0720
140.07470.07810.0641
150.06730.07030.0571
160.05980.06250.0508
170.05380.05630.0453
180.04780.05000.0403
190.04180.04380.0359
200.03590.03750.0320
210.03290.03440.0285
220.02990.03130.0253
230.02690.02810.0226
240.02390.02500.0201

Gauges 7–24; galvanized column, mm values, and gauges 25–30: sheet metal gauge chart.

Hardness conversion (ASTM E140, steel)

HRCHBHVksi
64—800—
62—746—
60—697—
58615653338
56577613313
54543577292
52512544273
50481513255
48455484238
46432458221
44409434208
42390412194
40371392182
38353372171
36336354161
34319336152
32301318146
30286302138
28271286131
26258272125
24247260119
22237248115
20226238110

Even HRC rows only; odd rows and MPa on the hardness conversion chart. — = beyond validated range.

Metal densities

Alloykg/m³lb/in³
Carbon Steel (A36 / mild)78500.284
Stainless Steel 30479300.286
Aluminum 606127000.098
Copper C110 (ETP)89400.323
Brass C260 (Cartridge)85300.308
Titanium Grade 245100.163
Gray Cast Iron (A48 Cl. 40)71500.258
Zinc71350.258
Lead113400.410

Datasheet-verified alloy densities; lb/in³ computed with exact 25.4 mm/in and 453.59237 g/lb.

Sources

  • ANSI/ASME B94.11M gauge drills
  • MSG / GSG / B&S published gauge tables
  • ASTM E140 hardness conversions (steel)
  • Manufacturer datasheet alloy densities

Try the Calculators

Tap Drill Size Calculator — Metric & UNC/UNF ThreadsMetal Weight Calculator — Steel, Aluminum, Plate, Bar & TubeBend Allowance Calculator — K-Factor, Bend Deduction & Flat Pattern

Machinist's Pocket Card — Drills, Gauges, Hardness & Densities — reuven.tools/cheat-sheets/machinist-pocket-card — verified against: ANSI/ASME B94.11M gauge drills; MSG / GSG / B&S published gauge tables; ASTM E140 hardness conversions (steel); Manufacturer datasheet alloy densities