Cad Build123d Bd Warehouse

bd_warehouse — Parametric Part Library for build123d

Prerequisite: Load cad-build123d-general first — bd_warehouse parts are returned as build123d Part objects and follow the same API conventions.

Purpose

Before modeling a common mechanical component from scratch, check whether bd_warehouse already provides a parametric version. It is the most-comprehensive build123d-native part library, written by the build123d author (Gumyr), and covers the vast majority of "I need a standard part" requests an agent will see.

This skill is the bd_warehouse reference. The Other build123d-compatible libraries appendix at the end points to a handful of niche libraries (py_gearworks for advanced gears, bd_vslot for V-Slot rails, etc.) and the separate cad-partcad-repository skill for the wider community-parts catalog.

When to Use This Skill

• The user asks for a bolt, screw, nut, washer, bearing, simple gear, sprocket, pipe, flange, helical thread, or heat-set insert hole.
• The user says "is there already a part for …?" or "I don't want to model X from scratch".
• You're about to hand-model a standard mechanical component — check here first.
• Need an advanced gear (helical, bevel, cycloid, profile shift, backlash control)? Bounce out to py_gearworks via the appendix below.
• Need a community part that isn't on bd_warehouse (e.g. an OpenVMP robot arm, a piece of furniture)? Bounce out to cad-partcad-repository.

Install

pip install git+https://github.com/gumyr/bd_warehouse

⚠️ Install from git — bd_warehouse is not currently published to PyPI. The git source tracks build123d's API closely; pinning a commit is wise for reproducibility.

Sub-packages

For practical FDM-printable threads (thumbscrews, captive nuts, printed-on-printed fits) load cad-build123d-printed-threads after this skill — it covers the patterns and the bd_warehouse thread bugs.

Fastener Quick Reference

Discovering available parts

from bd_warehouse.fastener import Nut, HexNut, Screw, SocketHeadCapScrew

# List all nut subclasses
Nut.__subclasses__()

# List types for a class
HexNut.types()          # {'iso4033', 'iso4032', 'iso4035'}

# List sizes for a type
HexNut.sizes("iso4032") # ['M1.6-0.35', 'M2-0.4', ..., 'M48-5']

# Find all fasteners that come in M6
Nut.select_by_size("M6-1")
Screw.select_by_size("M6-1")

Creating fasteners

from build123d import *
from bd_warehouse.fastener import HexNut, SocketHeadCapScrew, SetScrew

nut       = HexNut(size="M3-0.5", fastener_type="iso4032")
screw     = SocketHeadCapScrew(size="M6-1", fastener_type="iso4762", length=16)
setscrew  = SetScrew(size="M6-1", fastener_type="iso4026", length=10 * MM)

# Imperial sizes work too
cap_screw = SocketHeadCapScrew(
    size="#6-32", fastener_type="asme_b18.3", length=(1/2) * IN
)

Custom holes (the real power feature)

from bd_warehouse.fastener import (
    ClearanceHole, TapHole, InsertHole, HeatSetNut, SocketHeadCapScrew,
)

screw = SocketHeadCapScrew(size="M2-0.4", length=16)

with BuildPart() as block:
    Box(50, 50, 10)
    with Locations((0, 0, 10)):
        # Clearance hole sized to the screw — no manual dimensions needed
        ClearanceHole(fastener=screw, fit="Normal")

# For 3D-printed heat-set inserts
insert = HeatSetNut(size="M3-0.5-Standard", fastener_type="McMaster-Carr")
with BuildPart() as post:
    Cylinder(radius=5, height=10)
    with Locations((0, 0, 10)):
        InsertHole(fastener=insert)

Pillow block example (bearing + fasteners)

import copy
from bd_warehouse.bearing  import PressFitHole, SingleRowDeepGrooveBallBearing
from bd_warehouse.fastener import ClearanceHole, SocketHeadCapScrew
from build123d import *

cap_screw = SocketHeadCapScrew(size="M2-0.4", length=16, simple=False)
bearing   = SingleRowDeepGrooveBallBearing(size="M8-22-7")

with BuildPart() as pillow_block:
    with BuildSketch():
        RectangleRounded(50, 30, 2)
    extrude(amount=10)
    with Locations((0, 0, 10)):
        PressFitHole(bearing=bearing, interference=0.025 * MM)
        with GridLocations(38, 18, 2, 2):
            ClearanceHole(fastener=cap_screw)

Class Reference

Nut Classes

Screw Classes

Washer Classes

Hole Types

Thread Classes

IsoThread, AcmeThread, MetricTrapezoidalThread, TrapezoidalThread, PlasticBottleThread, plus the base Thread class for arbitrary helical profiles.

See cad-build123d-printed-threads for the FDM-printable patterns, the interference parameter, the end_finishes length-overrun gotcha, the algebra-fuse vs Compound multi-body trade-off, and the bugs that bite trapezoidal-thread Mode.SUBTRACT operations.

Performance Tip

All fastener classes accept simple=True (default) which omits thread geometry for dramatically faster rendering. Only set simple=False for final renders or assembly validation.

Docs

• Full docs: https://bd-warehouse.readthedocs.io/en/latest/
• Fasteners: https://bd-warehouse.readthedocs.io/en/latest/fastener.html
• Bearings: https://bd-warehouse.readthedocs.io/en/latest/bearing.html
• Gears: https://bd-warehouse.readthedocs.io/en/latest/gear.html
• Threads: https://bd-warehouse.readthedocs.io/en/latest/thread.html
• Source: https://github.com/gumyr/bd_warehouse

Other build123d-compatible part libraries

Brief pointers to libraries that handle niches bd_warehouse does not. Listed here so the agent has the catalog in one place; load the linked external docs for full API details.

py_gearworks (advanced gears)

By GarryBGoode. Use this when bd_warehouse.gear isn't enough.

pip install git+https://github.com/GarryBGoode/py_gearworks

from py_gearworks import SpurGear

g1 = SpurGear(number_of_teeth=12, module=2, height=4, profile_shift=0.3)
g2 = SpurGear(number_of_teeth=23, module=2, height=4)
g1.mesh_to(g2, target_dir=UP, backlash=0.1, angle_bias=1)

part_1 = g1.build_part()  # build123d Part
part_2 = g2.build_part()

Docs: https://gggears.readthedocs.io/en/latest/

Rule of thumb: Use bd_warehouse for sprockets and simple gears alongside fasteners. Use py_gearworks for anything with profile shift, bevel gears, helical meshing, or backlash control.

bd_vslot (V-Slot 2020 linear motion)

By James Keal. V-Slot 2020 rails, wheels, sliding T-nuts, end caps, build plates, common bearings (625, 688, 105).

pip install bd-vslot

Docs: https://bd-vslot.readthedocs.io/

bd_beams_and_bars (structural sections)

By ExperimentsLabs. Flat bars, IPE/HEA/HEB/HEM/IPN beams, L bars, rectangle/round tubes, T bars, UPE/UAP/UPN beams.

pip install git+https://gitlab.com/experimentslabs/3d/bd_beams_and_bars.git

from bd_beams_and_bars.profiles.flat_bars import Bar, Standards, Definition

part   = Bar(Standards.LFL.LFL_160x5, 500)
custom = Bar(Definition(w=43, h=9), 500)

Docs: https://bd-beams-and-bars.3d.experimentslabs.com/

For round pipes specifically, bd_warehouse.pipe is usually a better fit — NPS-standard parametric pipes with joints.

Superellipses & superellipsoids

By fanf2. Single-file Python module, not a pip package — copy superellipse.py into your project. Smooth alternative to rounded rectangles, useful for typeface-style key caps, app-icon-style clipping, organic phone-case shapes.

Public PartCAD repository

A package-manager-style ecosystem with hundreds of community-published parts and assemblies (electrical, electromechanics, electronics, furniture, medical, robotics, std, storage). Includes bd_warehouse parts, plus much more. Browse: https://partcad.org/repository.

Don't use this skill for PartCAD specifics. The cad-partcad-repository skill covers pip install partcad, pc.get_part_build123d(...), the CLI, and the AI-generated-part workflow. This entry is here only as a pointer.

Quick Decision Table

See Also

• Official build123d listing: https://build123d.readthedocs.io/en/latest/external.html#part-libraries
• cad-build123d-general — foundational build123d API + idioms (load first)
• cad-build123d-printed-threads — practical FDM-printable thread patterns + bd_warehouse thread bugs
• cad-partcad-repository — sibling skill, covers the PartCAD ecosystem in depth