JIS B 1018:2009 PDF Download

This Standard lays down the form and dimensions of thread undercuts for bolts, screws and similar externally threaded products, recommended for use in those cases where an undercut is needed for threaded components such as plugs, unless otherwise specified in the appropriate product standard.

NOTE: The International Standard corresponding to this Standard and the symbol of degree of correspondence are as follows:

ISO 4755 : 1983 Fasteners-Thread undercuts for external metric IS0 threads (IDT)

The symbols which denote the degree of correspondence in the contents between the relevant International Standard and JIS are IDT (identical), MOD (modified), and NEQ (not equivalent) according to ISO/ IEC Guide 21.