solid.threadspec
drafting: T = solid.threadspec (NAME)
drafting: T = solid.threadspec (NAME, ’Custom’, TF)
The dimensions of a metric screw thread, read from its name.
T = solid.threadspec (NAME) reads NAME as a
drawing names a thread, 'M6' for a coarse thread by its nominal
diameter and 'M10x1.25' for a fine one with its pitch, and
returns the numbers solid.Shape.hole and solid.Shape.thread
cut it by, as a struct with the fields:
name | NAME as given. |
d | The nominal diameter in millimetres. |
P | The pitch in millimetres. |
coarse | True for the coarse pitch of ISO 261, false for a fine or a custom one. |
custom | True for a thread outside ISO 261, taken with
'Custom'. |
minor | The 6H band of the minor diameter of the
internal thread, [min, max], from ISO 965-1. |
drill | The tapping drill solid.Shape.hole takes
without 'Material' or 'Engagement': the one ISO 2306
lists, or the nominal diameter less the pitch for a thread it does not
list. For a custom thread, the step of 0.05 inside the band nearest the
nominal diameter less the pitch, empty when the band holds none. |
major | The largest major diameter of the external
thread in class 6g, from ISO 965-1, which solid.Shape.thread turns
a rod at the nominal diameter down to. |
The names are those of ISO 261, table 2, from M1 to M64, all three of
its columns. A diameter with no coarse pitch is named with its pitch, as
'M15x1.5'.
T = solid.threadspec (NAME, 'Custom', TF) with
TF true takes a thread of any diameter and pitch, named with its
pitch, as 'M16x0.8' cut on a lathe or 'M6.35x1.27' for
1/4-20 UNC; its pitch and minor diameter must be positive. Without it a
name outside ISO 261 is refused, so that a mistyped name is caught.
Where each number comes from, and how it is computed, is set out on the Standards page of the guide.
## The tapping drill and the 6H band of M8
T = solid.threadspec ('M8');
T.drill
⇒ 6.8000
T.minor
⇒ 6.6468 6.9118
|
See also: solid.Shape.hole, solid.Shape.thread
Source Code: solid.threadspec