"""Hexagon head screw (fully threaded), ISO 4017 (DIN 933), M1.6 to M36, any length.

Envelope model for assemblies: hexagon head (width across flats s, height k, sharp corners) and a plain shank at the
nominal thread diameter d (the thread is not modelled). The head's bearing face is on the XY plane at the origin,
the head above it, the shank along -Z; `length` is the nominal length l, measured from under the head. Two flats of
the head are parallel to the X axis.
"""
from steve import Model

size = "M6"  # Thread size
length = 20  # mm Nominal length (under the head)
material = "steel"  # Material

# ISO 4017:2022, Tables 1-3 (official preview pp. 3-5:
# https://cdn.standards.iteh.ai/samples/72585/1179998ddd594550a909d6e13c416f3e/ISO-4017-2022.pdf); the same values in
# ISO 4017:2011 Table 1 and ISO 4017:2014 (M1.6-M6 seen). size: (thread d, width across flats s nominal, head height k nominal)
DIMENSIONS = {
    "M1.6": (1.6, 3.2, 1.1),
    "M2": (2.0, 4.0, 1.4),
    "M2.5": (2.5, 5.0, 1.7),
    "M3": (3.0, 5.5, 2.0),
    "M4": (4.0, 7.0, 2.8),
    "M5": (5.0, 8.0, 3.5),
    "M6": (6.0, 10.0, 4.0),
    "M8": (8.0, 13.0, 5.3),
    "M10": (10.0, 16.0, 6.4),
    "M12": (12.0, 18.0, 7.5),
    "M14": (14.0, 21.0, 8.8),
    "M16": (16.0, 24.0, 10.0),
    "M20": (20.0, 30.0, 12.5),
    "M24": (24.0, 36.0, 15.0),
    "M30": (30.0, 46.0, 18.7),
    "M36": (36.0, 55.0, 22.5),
}
# material choice: (STEVE material library id, appearance colour)
MATERIALS = {
    "steel": ("steel-generic", "#b4b8bd"),        # property class 8.8, zinc plated
    "stainless-a2": ("stainless-304", "#c9ccd0"),  # ISO 3506-1 A2-70
    "stainless-a4": ("stainless-316", "#c9ccd0"),  # ISO 3506-1 A4-70 / A4-80
}

d, s, k = DIMENSIONS[size]
material_id, colour = MATERIALS[material]

model = Model()
with model.sketch("head_sketch", on="XY", name="Head") as sk:
    sk.polygon("hex", (0, 0), s / 2, 6, inscribed=False)
model.extrude("head", "head_sketch", distance=k, name="Head")
with model.sketch("shank_sketch", on="XY", name="Shank") as sk:
    sk.circle("shank_circle", (0, 0), d / 2)
model.extrude("shank", "shank_sketch", distance=-length, name="Shank")
model.material(material_id, color=colour)
result = model.result()