feat(task-8): ISO fastener and ISO 15 bearing tables, transcribed and pinned

engineering/mech/standards/fasteners.py carries ISO 4014:2011 / ISO 4017:2014 head dimensions (s, k), ISO 4032:2012 nut heights, ISO 7089:2000 washer d1/d2/h and ISO 4762:2004 socket head cap screws, plus the ISO 261:1998 coarse pitch column. bearings.py carries the ISO 15:2017 deep groove boundary dimensions for 6000-6010, 6200-6210 and 6300-6310. Only the ISO 261 first-choice sizes ship. M14/M18/M22/M27/M33, everything above M36 (above M24 for ISO 4762), the 618x/619x/16xx bearing series, bore numbers above 10 and every suffixed bearing variant are refused by name rather than interpolated: a narrow table is merely narrow, a wrong row ships a wrong workshop drawing. Across-corners e is derived geometry (2s/sqrt(3)), so no e column had to be transcribed at all, and the ISO 8826-1 cross and ISO 8826-2 element-symbol fractions are declared drawing conventions, not table values. No ActiveX member is called by this task, so no live AutoCAD probe was needed; the two modules are pure tables and pure arithmetic. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
2026-09-22 18:53:17 +03:00
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+"""ISO 15 boundary dimensions and the ISO 8826 representation conventions."""
+
+from __future__ import annotations
+
+import pytest
+
+from engineering.mech.standards import standards
+from engineering.mech.standards.bearings import (
+    BALL_SYMBOL_FRACTION,
+    BEARING_SERIES,
+    CROSS_FRACTION,
+    DEEP_GROOVE,
+    SOURCE_ISO_15,
+    SOURCE_ISO_8826_1,
+    SOURCE_ISO_8826_2,
+    bearing,
+    list_bearings,
+)
+
+
+@pytest.mark.parametrize(
+    ("designation", "bore", "outer", "width"),
+    [
+        ("6000", 10.0, 26.0, 8.0),
+        ("6004", 20.0, 42.0, 12.0),
+        ("6006", 30.0, 55.0, 13.0),
+        ("6010", 50.0, 80.0, 16.0),
+        ("6200", 10.0, 30.0, 9.0),
+        ("6203", 17.0, 40.0, 12.0),
+        ("6205", 25.0, 52.0, 15.0),
+        ("6208", 40.0, 80.0, 18.0),
+        ("6210", 50.0, 90.0, 20.0),
+        ("6300", 10.0, 35.0, 11.0),
+        ("6305", 25.0, 62.0, 17.0),
+        ("6309", 45.0, 100.0, 25.0),
+        ("6310", 50.0, 110.0, 27.0),
+    ],
+)
+def test_named_rows_match_iso15(designation, bore, outer, width):
+    row = bearing(designation)
+    assert (row["d"], row["D"], row["B"]) == (bore, outer, width)
+    assert row["designation"] == designation
+    assert row["source"] == SOURCE_ISO_15
+
+
+def test_bore_number_rule_holds_across_every_series():
+    """ISO 15: bore 00/01/02/03 = 10/12/15/17 mm; 04 and up = 5 x bore number."""
+    for series in ("60", "62", "63"):
+        assert bearing(f"{series}00")["d"] == 10.0
+        assert bearing(f"{series}01")["d"] == 12.0
+        assert bearing(f"{series}02")["d"] == 15.0
+        assert bearing(f"{series}03")["d"] == 17.0
+        for n in range(4, 11):
+            assert bearing(f"{series}{n:02d}")["d"] == 5.0 * n
+
+
+def test_outside_diameter_and_width_grow_with_the_series():
+    for n in range(0, 11):
+        light = bearing(f"60{n:02d}")
+        medium = bearing(f"62{n:02d}")
+        heavy = bearing(f"63{n:02d}")
+        assert light["d"] == medium["d"] == heavy["d"]
+        assert light["D"] < medium["D"] < heavy["D"]
+        assert light["B"] < medium["B"] < heavy["B"]
+
+
+def test_coverage_refusals_name_the_table():
+    with pytest.raises(ValueError, match="ISO 15"):
+        bearing("6011")
+    with pytest.raises(ValueError, match="ISO 15"):
+        bearing("6211")
+    with pytest.raises(ValueError, match="ISO 15"):
+        bearing("6311")
+    with pytest.raises(ValueError, match="ISO 15"):
+        bearing("61805")  # the 618x light series is not transcribed
+    with pytest.raises(ValueError, match="ISO 15"):
+        bearing("6205-2RS")  # a seal suffix is a variant this table does not carry
+
+
+def test_representation_fractions_are_declared_conventions_not_table_values():
+    assert 0.0 < CROSS_FRACTION < 1.0
+    assert 0.0 < BALL_SYMBOL_FRACTION < 1.0
+    assert "ISO 8826-1" in SOURCE_ISO_8826_1
+    assert "ISO 8826-2" in SOURCE_ISO_8826_2
+    assert "ISO 15:2017" in SOURCE_ISO_15
+
+
+def test_the_element_symbol_always_fits_inside_the_ring_rectangle():
+    """The declared fractions must never draw a symbol outside the envelope."""
+    for name in DEEP_GROOVE:
+        row = bearing(name)
+        half_width = row["B"] / 2.0
+        half_gap = (row["D"] - row["d"]) / 4.0
+        assert BALL_SYMBOL_FRACTION * half_gap < half_width
+        assert CROSS_FRACTION * half_width < half_width
+        assert CROSS_FRACTION * half_gap < half_gap
+
+
+def test_list_bearings_filters_by_series():
+    assert len(DEEP_GROOVE) == 33
+    assert len(list_bearings()) == 33
+    assert BEARING_SERIES == ("600x", "620x", "630x")
+    assert {row["designation"] for row in list_bearings("620x")} == {
+        f"62{n:02d}" for n in range(11)
+    }
+    with pytest.raises(ValueError, match="620x"):
+        list_bearings("622x")
+
+
+def test_the_table_registers_itself():
+    assert "ISO 15" in standards()
@@ -0,0 +1,189 @@
+"""Provenance and coverage of the ISO fastener tables (the table rule, spec 5).
+
+Every value asserted here is a named row of a named table. A row that could not
+be verified against the standard is not in the module at all, so the coverage
+refusals below are as load-bearing as the values.
+"""
+
+from __future__ import annotations
+
+import math
+
+import pytest
+
+from engineering.mech.standards import standards
+from engineering.mech.standards.fasteners import (
+    COARSE_PITCH,
+    HEX_NUT,
+    SOCKET_HEAD,
+    SOURCE_ISO_4014,
+    across_corners,
+    hex_head,
+    hex_nut,
+    nominal_diameter,
+    sizes,
+    socket_head,
+    thread_length,
+    thread_pitch,
+    washer,
+)
+
+
+def test_iso4014_named_rows_match_the_standard():
+    """ISO 4014:2011 Table 1 - width across flats s and head height k."""
+    assert (hex_head("M6")["s"], hex_head("M6")["k"]) == (10.0, 4.0)
+    assert (hex_head("M8")["s"], hex_head("M8")["k"]) == (13.0, 5.3)
+    assert (hex_head("M10")["s"], hex_head("M10")["k"]) == (16.0, 6.4)
+    assert (hex_head("M12")["s"], hex_head("M12")["k"]) == (18.0, 7.5)
+    assert (hex_head("M16")["s"], hex_head("M16")["k"]) == (24.0, 10.0)
+    assert (hex_head("M20")["s"], hex_head("M20")["k"]) == (30.0, 12.5)
+    assert (hex_head("M24")["s"], hex_head("M24")["k"]) == (36.0, 15.0)
+    assert (hex_head("M30")["s"], hex_head("M30")["k"]) == (46.0, 18.7)
+    assert (hex_head("M36")["s"], hex_head("M36")["k"]) == (55.0, 22.5)
+
+
+def test_iso4017_shares_the_iso4014_head():
+    """ISO 4017 screws and ISO 4014 bolts have the same head at every size here."""
+    assert sizes("ISO 4017") == sizes("ISO 4014")
+
+
+def test_iso4032_named_rows_match_the_standard():
+    """ISO 4032:2012 Table 1 - nut height m (max)."""
+    assert hex_nut("M6")["m"] == 5.2
+    assert hex_nut("M8")["m"] == 6.8
+    assert hex_nut("M10")["m"] == 8.4
+    assert hex_nut("M12")["m"] == 10.8
+    assert hex_nut("M16")["m"] == 14.8
+    assert hex_nut("M20")["m"] == 18.0
+    assert hex_nut("M24")["m"] == 21.5
+    assert hex_nut("M30")["m"] == 25.6
+    assert hex_nut("M36")["m"] == 31.0
+    for size in HEX_NUT:
+        assert hex_nut(size)["s"] == hex_head(size)["s"]
+
+
+def test_iso7089_named_rows_match_the_standard():
+    """ISO 7089:2000 Table 1 - d1, d2, h (nominal), normal series, grade A."""
+    assert (washer("M6")["d1"], washer("M6")["d2"], washer("M6")["h"]) == (6.4, 12.0, 1.6)
+    assert (washer("M8")["d1"], washer("M8")["d2"], washer("M8")["h"]) == (8.4, 16.0, 1.6)
+    assert (washer("M10")["d1"], washer("M10")["d2"], washer("M10")["h"]) == (10.5, 20.0, 2.0)
+    assert (washer("M12")["d1"], washer("M12")["d2"], washer("M12")["h"]) == (13.0, 24.0, 2.5)
+    assert (washer("M16")["d1"], washer("M16")["d2"], washer("M16")["h"]) == (17.0, 30.0, 3.0)
+    assert (washer("M20")["d1"], washer("M20")["d2"], washer("M20")["h"]) == (21.0, 37.0, 3.0)
+    assert (washer("M24")["d1"], washer("M24")["d2"], washer("M24")["h"]) == (25.0, 44.0, 4.0)
+    assert (washer("M30")["d1"], washer("M30")["d2"], washer("M30")["h"]) == (31.0, 56.0, 4.0)
+    assert (washer("M36")["d1"], washer("M36")["d2"], washer("M36")["h"]) == (37.0, 66.0, 5.0)
+
+
+def test_iso4762_named_rows_match_the_standard():
+    """ISO 4762:2004 Table 1 - head dk (max), socket s, thread length b."""
+    assert (
+        socket_head("M3")["dk"],
+        socket_head("M3")["s"],
+        socket_head("M3")["b"],
+    ) == (5.5, 2.5, 18.0)
+    assert (
+        socket_head("M5")["dk"],
+        socket_head("M5")["s"],
+        socket_head("M5")["b"],
+    ) == (8.5, 4.0, 22.0)
+    assert (
+        socket_head("M8")["dk"],
+        socket_head("M8")["s"],
+        socket_head("M8")["b"],
+    ) == (13.0, 6.0, 28.0)
+    assert (
+        socket_head("M12")["dk"],
+        socket_head("M12")["s"],
+        socket_head("M12")["b"],
+    ) == (18.0, 10.0, 36.0)
+    assert (
+        socket_head("M20")["dk"],
+        socket_head("M20")["s"],
+        socket_head("M20")["b"],
+    ) == (30.0, 17.0, 52.0)
+    assert (
+        socket_head("M24")["dk"],
+        socket_head("M24")["s"],
+        socket_head("M24")["b"],
+    ) == (36.0, 19.0, 60.0)
+    # ISO 4762 head height equals the nominal thread diameter at every size here.
+    for size in SOCKET_HEAD:
+        assert socket_head(size)["k"] == nominal_diameter(size)
+
+
+def test_iso261_coarse_pitch_column():
+    assert COARSE_PITCH == {
+        "M3": 0.5,
+        "M4": 0.7,
+        "M5": 0.8,
+        "M6": 1.0,
+        "M8": 1.25,
+        "M10": 1.5,
+        "M12": 1.75,
+        "M16": 2.0,
+        "M20": 2.5,
+        "M24": 3.0,
+        "M30": 3.5,
+        "M36": 4.0,
+    }
+    assert thread_pitch("M12") == 1.75
+    assert nominal_diameter("M12") == 12.0
+
+
+def test_coverage_is_refused_at_both_ends_by_name():
+    with pytest.raises(ValueError, match="ISO 4014"):
+        hex_head("M3")
+    with pytest.raises(ValueError, match="ISO 4014"):
+        hex_head("M42")
+    with pytest.raises(ValueError, match="ISO 4032"):
+        hex_nut("M42")
+    with pytest.raises(ValueError, match="ISO 7089"):
+        washer("M3")
+    with pytest.raises(ValueError, match="ISO 4762"):
+        socket_head("M2")
+    with pytest.raises(ValueError, match="ISO 4762"):
+        socket_head("M30")
+
+
+def test_second_choice_sizes_are_absent_not_interpolated():
+    for absent in ("M14", "M18", "M22", "M27", "M33"):
+        with pytest.raises(ValueError):
+            hex_head(absent)
+        with pytest.raises(ValueError):
+            hex_nut(absent)
+
+
+def test_thread_length_follows_the_standards_own_b_rule():
+    assert thread_length("M12", 60.0) == pytest.approx(30.0)  # 2d + 6,  l <= 125
+    assert thread_length("M12", 150.0) == pytest.approx(36.0)  # 2d + 12, 125 < l <= 200
+    assert thread_length("M12", 260.0) == pytest.approx(49.0)  # 2d + 25, l > 200
+    assert thread_length("M12", 25.0) == pytest.approx(25.0)  # never longer than the bolt
+    assert thread_length("M12", 60.0, "ISO 4017") == pytest.approx(60.0)
+    assert thread_length("M8", 30.0, "ISO 4762") == pytest.approx(28.0)
+    assert thread_length("M8", 20.0, "ISO 4762") == pytest.approx(20.0)
+    with pytest.raises(ValueError):
+        thread_length("M12", 0.0)
+    with pytest.raises(ValueError):
+        thread_length("M12", float("inf"))
+    with pytest.raises(ValueError, match="ISO 4014"):
+        thread_length("M12", 60.0, "DIN 931")
+
+
+def test_across_corners_is_derived_geometry_not_a_transcribed_column():
+    assert across_corners(18.0) == pytest.approx(2.0 * 18.0 / math.sqrt(3.0))
+    assert across_corners(18.0) == pytest.approx(20.7846, abs=1e-4)
+    with pytest.raises(ValueError):
+        across_corners(0.0)
+
+
+def test_every_table_registers_itself_with_the_shared_registry():
+    for name in ("ISO 4014", "ISO 4017", "ISO 4032", "ISO 7089", "ISO 4762"):
+        assert name in standards()
+    assert "ISO 4014:2011" in SOURCE_ISO_4014
+
+
+def test_sizes_refuses_a_standard_this_module_does_not_carry():
+    assert sizes("ISO 4014")[0] == "M5"
+    with pytest.raises(ValueError, match="ISO 4014"):
+        sizes("ISO 15")