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Metric buttress

Metric buttress uses a 3° load flank and a 30° clearance flank, with metric pitch and separate external and internal tolerance settings.

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Example designation

S12 x 2-7e

S
Metric buttress thread designation.
12
Nominal major diameter of 12 mm.
2
Pitch of 2 mm.
7e
Pitch-diameter grade 7 at external position e.
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Keep the flank angles with the callout

The 3° and 30° flanks differ from the 7° and 45° inch buttress form. Use the metric profile geometry when specifying a tool or checking an existing thread.

Grades and added clearance

Select pitch grade 7, 8, or 9 and the required position. External diameter grade 9 and internal diameter grade 4 are fixed. Review any additional-clearance selection alongside the pitch- and minor-diameter limits.