5/8-8 ACME Thread Dimensions

Basic information

Designation

5/8-8 ACME

Thread system

ACME

Series

acme

Standard

ASME B1.5

Basic profile

ACME basic profile

Flank angle

29°

Dimensions

Major diameter

0.6252 in / 15.88 mm

Pitch (metric equivalent)

3.175 mm

Threads per inch

8

Pitch diameter

0.5626 in / 14.29 mm

Minor diameter (external)

0.4799 in / 12.19 mm

Minor diameter (internal)

0.4799 in / 12.19 mm

Thread depth

0.0725 in / 1.841 mm

Recommended tap drill

Ø 0.5 in / 12.7 mm

These figures follow the ACME basic profile of ASME B1.5. A 60° basic profile uses a fundamental triangle height H = 0.866025 × P, with external minor diameter d₃ = d − 1.226869 × P and internal minor diameter D₁ = d − 1.082532 × P; the two differ because the external root is rounded while the internal crest is truncated. A 55° Whitworth profile uses H = 0.960491 × P and a thread height of 0.640327 × P. The recommended tap drill is given as nominal diameter minus pitch, which approximates 75% thread engagement — adjust it for tough materials or deep holes.

No specification in this database uses 5/8-8 ACME. Power threads are not fastener threads — they are found on lead screws, jacks and vice screws, so no bolt or nut in this catalogue is made in this form. The geometry above is what a machinist needs to cut it.

Neighbouring sizes in ACME.