Inch Thread Gage Pitch Diameters

(Sizes #0 Through 1/2")

Typical thread class usage:

A class 1A external thread and a class 1B internal thread gives a loose fit.

A class 2A external thread and a class 2B internal thread gives a normal fit.

A class 3A external thread and a class 3B internal thread gives a close fit.

Classes 1A, 2A, and 3A gages are thread ring gages to check external threads.

Classes 1B, 2B, and 3B gages are thread plug gages to check internal threads.

Next Page

Fractional Thread Size

Decimal Thread Size

Go Pitch Diameter

(P.D.)

No Go Pitch Diameter

(P.D.)

#0-80 UNF-1A

.0600-80 UNF-1A

.0514"

.0488"

#0-80 UNF-1B

.0600-80 UNF-1B

.0519"

.0553"

#0-80 UNF-2A

.0600-80 UNF-2A

.0514"

.0496"

#0-80 UNF-2B

.0600-80 UNF-2B

.0519"

.0542"

#0-80 UNF-3A

.0600-80 UNF-3A

.0519"

.0506"

#0-80 UNF-3B

.0600-80 UNF-3B

.0519"

.0536"

#1-64 UNC-1A

.0730-64 UNC-1A

.0623"

.0593"

#1-64 UNC-1B

.0730-64 UNC-1B

.0629"

.0667"

#1-64 UNC-2A

.0730-64 UNC-2A

.0623"

.0603"

#1-64 UNC-2B

.0730-64 UNC-2B

.0629"

.0655"

#1-64 UNC-3A

.0730-64 UNC-3A

.0629"

.0614"

#1-64 UNC-3B

.0730-64 UNC-3B

.0629"

.0648"

#1-72 UNF-1A

.0730-72 UNF-1A

.0634"

.0606"

#1-72 UNF-1B

.0730-72 UNF-1B

.0640"

.0677"

#1-72 UNF-2A

.0730-72 UNF-2A

.0634"

.0615"

#1-72 UNF-2B

.0730-72 UNF-2B

.0640"

.0665"

#1-72 UNF-3A

.0730-72 UNF-3A

.0640"

.0626"

#1-72 UNF-3B

.0730-72 UNF-3B

.0640"

.0659"

#2-56 UNC-1A

.0860-56 UNC-1A

.0738"

.0706"

#2-56 UNC-1B

.0860-56 UNC-1B

.0744"

.0785"

#2-56 UNC-2A

.0860-56 UNC-2A

.0738"

.0717"

#2-56 UNC-2B

.0860-56 UNC-2B

.0744"

.0772"

#2-56 UNC-3A

.0860-56 UNC-3A

.0744"

.0728"

#2-56 UNC-3B

.0860-56 UNC-3B

.0744"

.0765"

#2-64 UNF-1A

.0860-64 UNF-1A

.0753"

.0722"

#2-64 UNF-1B

.0860-64 UNF-1B

.0759"

.0799"

#2-64 UNF-2A

.0860-64 UNF-2A

.0753"

.0733"

#2-64 UNF-2B

.0860-64 UNF-2B

.0759"

.0786"

#2-64 UNF-3A

.0860-64 UNF-3A

.0759"

.0744"

#2-64 UNF-3B

.0860-64 UNF-3B

.0759"

.0779"

#3-48 UNC-1A

.0990-48 UNC-1A

.0848"

.0813"

#3-48 UNC-1B

.0990-48 UNC-1B

.0855"

.0900"

#3-48 UNC-2A

.0990-48 UNC-2A

.0848"

.0825"

#3-48 UNC-2B

.0990-48 UNC-2B

.0855"

.0885"

#3-48 UNC-3A

.0990-48 UNC-3A

.0855"

.0838"

#3-48 UNC-3B

.0990-48 UNC-3B

.0855"

.0877"

#3-56 UNF-1A

.0990-56 UNF-2A

.0867"

.0834"

#3-56 UNF-1B

.0990-56 UNF-2B

.0874"

.0917"

#3-56 UNF-2A

.0990-56 UNF-2A

.0867"

.0845"

#3-56 UNF-2B

.0990-56 UNF-2B

.0874"

.0902"

#3-56 UNF-3A

.0990-56 UNF-3A

.0874"

.0858"

#3-56 UNF-3B

.0990-56 UNF-3B

.0874"

.0895"

#4-40 UNC-1A

.1120-40 UNC-1A

.0950"

.0912"

#4-40 UNC-1B

.1120-40 UNC-1B

.0958"

.1007"

#4-40 UNC-2A

.1120-40 UNC-2A

.0950"

.0925"

#4-40 UNC-2B

.1120-40 UNC-2B

.0958"

.0991"

#4-40 UNC-3A

.1120-40 UNC-3A

.0958"

.0939"

#4-40 UNC-3B

.1120-40 UNC-3B

.0958"

.0982"

#4-48 UNF-1A

.1120-48 UNF-1A

.0978"

.0943"

#4-48 UNF-1B

.1120-48 UNF-1B

.0985"

.1031"

#4-48 UNF-2A

.1120-48 UNF-2A

.0978"

.0954"

#4-48 UNF-2B

.1120-48 UNF-2B

.0985"

.1016"

#4-48 UNF-3A

.1120-48 UNF-3A

.0985"

.0967"

#4-48 UNF-3B

.1120-48 UNF-3B

.0985"

.1008"

#5-40 UNC-1A

.1250-40 UNC-1A

.1080"

.1042"

#5-40 UNC-1B

.1250-40 UNC-1B

.1088"

.1138"

#5-40 UNC-2A

.1250-40 UNC-2A

.1080"

.1054"

#5-40 UNC-2B

.1250-40 UNC-2B

.1088"

.1121"

#5-40 UNC-3A

.1250-40 UNC-3A

.1088"

.1069"

#5-40 UNC-3B

.1250-40 UNC-3B

.1088"

.1113"

#5-44 UNF-1A

.1250-44 UNF-1A

.1095"

.1058"

#5-44 UNF-1B

.1250-44 UNF-1B

.1102"

.1150"

#5-44 UNF-2A

.1250-44 UNF-2A

.1095"

.1070"

#5-44 UNF-2B

.1250-44 UNF-2B

.1102"

.1134"

#5-44 UNF-3A

.1250-44 UNF-3A

.1102"

.1083"

#5-44 UNF-3B

.1250-44 UNF-3B

.1102"

.1126"

#6-32 UNC-1A

.1380-32 UNC-1A

.1169"

.1127"

#6-32 UNC-1B

.1380-32 UNC-1B

.1177"

.1232"

#6-32 UNC-2A

.1380-32 UNC-2A

.1169"

.1141"

#6-32 UNC-2B

.1380-32 UNC-2B

.1177"

.1214"

#6-32 UNC-3A

.1380-32 UNC-3A

.1177"

.1156"

#6-32 UNC-3B

.1380-32 UNC-3B

.1177"

.1204"

#6-40 UNF-1A

.1380-40 UNF-1A

.1210"

.1171"

#6-40 UNF-1B

.1380-40 UNF-1B

.1218"

.1269"

#6-40 UNF-2A

.1380-40 UNF-2A

.1210"

.1184"

#6-40 UNF-2B

.1380-40 UNF-2B

.1218"

.1252"

#6-40 UNF-3A

.1380-40 UNF-3A

.1218"

.1198"

#6-40 UNF-3B

.1380-40 UNF-3B

.1218"

.1243"

#8-32 UNC-1A

.1640-32 UNC-1A

.1428"

.1384"

#8-32 UNC-1B

.1640-32 UNC-1B

.1437"

.1494"

#8-32 UNC-2A

.1640-32 UNC-2A

.1428"

.1399"

#8-32 UNC-2B

.1640-32 UNC-2B

.1437"

.1475"

#8-32 UNC-3A

.1640-32 UNC-3A

.1437"

.1415"

#8-32 UNC-3B

.1640-32 UNC-3B

.1437"

.1465"

#8-36 UNF-1A

.1640-36 UNF-1A

.1452"

.1410"

#8-36 UNF-1B

.1640-36 UNF-1B

.1460"

.1515"

#8-36 UNF-2A

.1640-36 UNF-2A

.1452"

.1424"

#8-36 UNF-2B

.1640-36 UNF-2B

.1460"

.1496"

#8-36 UNF-3A

.1640-36 UNF-3A

.1460"

.1439"

#8-36 UNF-3B

.1640-36 UNF-3B

.1460"

.1487"

#10-24 UNC-1A

.1900-24 UNC-1A

.1619"

.1569"

#10-24 UNC-1B

.1900-24 UNC-2B

.1629"

.1694"

#10-24 UNC-2A

.1900-24 UNC-2A

.1619"

.1586"

#10-24 UNC-2B

.1900-24 UNC-2B

.1629"

.1672"

#10-24 UNC-3A

.1900-24 UNC-3A

.1629"

.1604"

#10-24 UNC-3B

.1900-24 UNC-3B

.1629"

.1661"

#10-28 UNS-1A

.1900-28 UNS-1A

.1658"

.1608"

#10-28 UNS-1B

.1900-28 UNS-1B

.1668"

.1733"

#10-28 UNS-2A

.1900-28 UNS-2A

.1658"

.1625"

#10-28 UNS-2B

.1900-28 UNS-2B

.1668"

.1711"

#10-28 UNS-3A

.1900-28 UNS-3A

.1668"

.1643"

#10-28 UNS-3B

.1900-28 UNS-3B

.1668"

.1701"

#10-32 UNF-1A

.1900-32 UNF-1A

.1688"

.1643"

#10-32 UNF-1B

.1900-32 UNF-1B

.1697"

.1756"

#10-32 UNF-2A

.1900-32 UNF-2A

.1688"

.1658"

#10-32 UNF-2B

.1900-32 UNF-2B

.1697"

.1736"

#10-32 UNF-3A

.1900-32 UNF-3A

.1697"

.1674"

#10-32 UNF-3B

.1900-32 UNF-3B

.1697"

.1726"

#10-36 UNS-1A

.1900-36 UNS-1A

.1711"

.1666"

#10-36 UNS-1B

.1900-36 UNS-1B

.1720"

.1778"

#10-36 UNS-2A

.1900-36 UNS-2A

.1711"

.1681"

#10-36 UNS-2B

.1900-36 UNS-2B

.1720"

.1759"

#10-36 UNS-3A

.1900-36 UNS-3A

.1720"

.1698"

#10-36 UNS-3B

.1900-36 UNS-3B

.1720"

.1749"

#10-40 UNS-1A

.1900-40 UNS-1A

.1729"

.1686"

#10-40 UNS-1B

.1900-40 UNS-1B

.1738"

.1794"

#10-40 UNS-2A

.1900-40 UNS-2A

.1729"

.1700"

#10-40 UNS-2B

.1900-40 UNS-2B

.1738"

.1775"

#10-40 UNS-3A

.1900-40 UNS-3A

.1738"

.1717"

#10-40 UNS-3B

.1900-40 UNS-3B

.1738"

.1766"

#10-48 UNS-1A

.1900-48 UNS-1A

.1757"

.1717"

#10-48 UNS-1B

.1900-48 UNS-1B

.1765"

.1817"

#10-48 UNS-2A

.1900-48 UNS-2A

.1757"

.1731"

#10-48 UNS-2B

.1900-48 UNS-2B

.1765"

.1799"

#10-48 UNS-3A

.1900-48 UNS-3A

.1765"

.1745"

#10-48 UNS-3B

.1900-48 UNS-3B

.1765"

.1791"

#10-56 UNS-1A

.1900-56 UNS-1A

.1777"

.1740"

#10-56 UNS-1B

.1900-56 UNS-1B

.1784"

.1833"

#10-56 UNS-2A

.1900-56 UNS-2A

.1777"

.1752"

#10-56 UNS-2B

.1900-56 UNS-2B

.1784"

.1816"

#10-56 UNS-3A

.1900-56 UNS-3A

.1784"

.1765"

#10-56 UNS-3B

.1900-56 UNS-3B

.1784"

.1808"

#12-24 UNC-1A

.2160-24 UNC-1A

.1879"

.1828"

#12-24 UNC-1B

.2160-24 UNC-1B

.1889"

.1955"

#12-24 UNC-2A

.2160-24 UNC-2A

.1879"

.1845"

#12-24 UNC-2B

.2160-24 UNC-2B

.1889"

.1933"

#12-24 UNC-3A

.2160-24 UNC-3A

.1889"

.1863"

#12-24 UNC-3B

.2160-24 UNC-3B

.1889"

.1922"

#12-28 UNF-1A

.2160-28 UNF-1A

.1918"

.1870"

#12-28 UNF-1B

.2160-28 UNF-1B

.1928"

.1991"

#12-28 UNF-2A

.2160-28 UNF-2A

.1918"

.1886"

#12-28 UNF-2B

.2160-28 UNF-2B

.1928"

.1970"

#12-28 UNF-3A

.2160-28 UNF-3A

.1928"

.1904"

#12-28 UNF-3B

.2160-28 UNF-3B

.1928"

.1959"

#12-32 UNEF-1A

.2160-32 UNEF-1A

.1947"

.1899"

#12-32 UNEF-1B

.2160-32 UNEF-1B

.1957"

.2019"

#12-32 UNEF-2A

.2160-32 UNEF-2A

.1947"

.1915"

#12-32 UNEF-2B

.2160-32 UNEF-2B

.1957"

.1998"

#12-32 UNEF-3A

.2160-32 UNEF-3A

.1957"

.1933"

#12-32 UNEF-3B

.2160-32 UNEF-3B

.1957"

.1988"

#12-36 UNS-1A

.2160-36 UNS-1A

.1971"

.1926"

#12-36 UNS-1B

.2160-36 UNS-1B

.1980"

.2039"

#12-36 UNS-2A

.2160-36 UNS-2A

.1971"

.1941"

#12-36 UNS-2B

.2160-36 UNS-2B

.1980"

.2019"

#12-36 UNS-3A

.2160-36 UNS-3A

.1980"

.1957"

#12-36 UNS-3B

.2160-36 UNS-3B

.1980"

.2010"

#12-40 UNS-1A

.2160-40 UNS-1A

.1989"

.1946"

#12-40 UNS-1B

.2160-40 UNS-1B

.1998"

.2054"

#12-40 UNS-2A

.2160-40 UNS-2A

.1989"

.1960"

#12-40 UNS-2B

.2160-40 UNS-2B

.1998"

.2035"

#12-40 UNS-3A

.2160-40 UNS-3A

.1998"

.1976"

#12-40 UNS-3B

.2160-40 UNS-3B

.1998"

.2026"

#12-48 UNS-1A

.2160-48 UNS-1A

.2017"

.1977"

#12-48 UNS-1B

.2160-48 UNS-1B

.2025"

.2077"

#12-48 UNS-2A

.2160-48 UNS-2A

.2017"

.1991"

#12-48 UNS-2B

.2160-48 UNS-2B

.2025"

.2059"

#12-48 UNS-3A

.2160-48 UNS-3A

.2025"

.2005"

#12-48 UNS-3B

.2160-48 UNS-3B

.2025"

.2051"

#12-56 UNS-1A

.2160-56 UNS-1A

.2036"

.1998"

#12-56 UNS-1B

.2160-56 UNS-1B

.2044"

.2093"

#12-56 UNS-2A

.2160-56 UNS-2A

.2036"

.2011"

#12-56 UNS-2B

.2160-56 UNS-2B

.2044"

.2076"

#12-56 UNS-3A

.2160-56 UNS-3A

.2044"

.2025"

#12-56 UNS-3B

.2160-56 UNS-3B

.2044"

.2069"

1/4-20 UNC-1A

.2500-20 UNC-1A

.2164"

.2108"

1/4-20 UNC-1B

.2500-20 UNC-1B

.2175"

.2248"

1/4-20 UNC-2A

.2500-20 UNC-2A

.2164"

.2127"

1/4-20 UNC-2B

.2500-20 UNC-2B

.2175"

.2224"

1/4-20 UNC-3A

.2500-20 UNC-3A

.2175"

.2147"

1/4-20 UNC-3B

.2500-20 UNC-3B

.2175"

.2211"

1/4-24 UNS-1A

.2500-24 UNS-1A

.2218"

.2163"

1/4-24 UNS-1B

.2500-24 UNS-1B

.2229"

.2301"

1/4-24 UNS-2A

.2500-24 UNS-2A

.2218"

.2181"

1/4-24 UNS-2B

.2500-24 UNS-2B

.2229"

.2227"

1/4-24 UNS-3A

.2500-24 UNS-3A

.2229"

.2201"

1/4-24 UNS-3B

.2500-24 UNS-3B

.2229"

.2265"

1/4-27 UNS-1A

.2500-27 UNS-1A

.2249"

.2197"

1/4-27 UNS-1B

.2500-27 UNS-1B

.2259"

.2327"

1/4-27 UNS-2A

.2500-27 UNS-2A

.2249"

.2214"

1/4-27 UNS-2B

.2500-27 UNS-2B

.2259"

.2304"

1/4-27 UNS-3A

.2500-27 UNS-3A

.2259"

.2233"

1/4-27 UNS-3B

.2500-27 UNS-3B

.2259"

.2293"

1/4-28 UNF-1A

.2500-28 UNF-1A

.2258"

.2208"

1/4-28 UNF-1B

.2500-28 UNF-1B

.2268"

.2333"

1/4-28 UNF-2A

.2500-28 UNF-2A

.2258"

.2225"

1/4-28 UNF-2B

.2500-28 UNF-2B

.2268"

.2311"

1/4-28 UNF-3A

.2500-28 UNF-3A

.2268"

.2243"

1/4-28 UNF-3B

.2500-28 UNF-3B

.2268"

.2300"

1/4-32 UNEF-1A

.2500-32 UNEF-1A

.2287"

.2239"

1/4-32 UNEF-1B

.2500-32 UNEF-1B

.2297"

.2260"

1/4-32 UNEF-2A

.2500-32 UNEF-2A

.2287"

.2255"

1/4-32 UNEF-2B

.2500-32 UNEF-2B

.2297"

.2339"

1/4-32 UNEF-3A

.2500-32 UNEF-3A

.2297"

.2273"

1/4-32 UNEF-3B

.2500-32 UNEF-3B

.2297"

.2328"

1/4-36 UNS-1A

.2500-36 UNS-1A

.2311"

.2265"

1/4-36 UNS-1B

.2500-36 UNS-1B

.2320"

.2380"

1/4-36 UNS-2A

.2500-36 UNS-2A

.2311"

.2280"

1/4-36 UNS-2B

.2500-36 UNS-2B

.2320"

.2360"

1/4-36 UNS-3A

.2500-36 UNS-3A

.2320"

.229