threads-scad OpenSCAD Library

The threads.scad module is an efficient OpenSCAD library designed to be used as a component in larger 3D designs. It provides tools for generating metric-compatible internal and external threads, auger threads, tapered threads, and various hardware components like hex bolts, nuts, washers, and Phillips tips.

Key technical advantages include:

• Performance: Uses list comprehensions to generate threads as a single polyhedron, improving rendering speed and robustness.
• Quality: Decreases facet count and increases tactile smoothness compared to other approaches.
• Versatility: Supports partially tapered ends, auger threads, and conventional threads that come to a point.

To successfully print threaded parts using this library, consider the following:

• Calibration: Ensure your printer is properly calibrated for extrusion width and produces consistent, stable parts.
• Thread Sizing:
  • M2 and higher: Internal threads (holes) generally work well with standard metal bolts.
  • M3: External threads work under good conditions but are sensitive to print quality changes.
  • M4 and higher: Generally very reliable.
• Tall Rods: Use the RodStart, RodEnd, and RodExtender modules to print vertical rods taller than your printer's height. These can be quite sturdy when printed with appropriate infill and plastic settings.

The following modules are used to generate threaded geometry. Note that parameters with a default of 0 or -1 often indicate that a standard default value will be calculated internally if not overridden.

// External threads
module ScrewThread(outer_diam, height, pitch=0, tooth_angle=30, tolerance=0.4, tip_height=0, tooth_height=0, tip_min_fract=0)

// External auger-style threads
module AugerThread(outer_diam, inner_diam, height, pitch, tooth_angle=30, tolerance=0.4, tip_height=0, tip_min_fract=0)

// Internal screw threads (hole)
module ScrewHole(outer_diam, height, position=[0,0,0], rotation=[0,0,0], pitch=0, tooth_angle=30, tolerance=0.4, tooth_height=0)

// Internal auger-style threads (hole)
module AugerHole(outer_diam, inner_diam, height, pitch, position=[0,0,0], rotation=[0,0,0], tooth_angle=30, tolerance=0.4)

The library provides several functions to retrieve standard metric values for a given diameter, which can be used to ensure compatibility in your own calculations:

• ThreadPitch
• HexAcrossFlats
• HexAcrossCorners
• HexDriveAcrossFlats
• HexDriveAcrossCorners
• CountersunkDriveAcrossFlats
• CountersunkDriveAcrossCorners
• NutThickness

Additionally, ClosePoints(pointarrays) generates a closed polyhedron from an array of point loops (N arrays of P points) following the right-hand rule.

These modules support creating long rods by combining solid sections with threaded joints. This is useful for printing vertical rods taller than the printer's Z-axis height.

// Solid rod on bottom, external threads on top
module RodStart(diameter, height, thread_len=0, thread_diam=0, thread_pitch=0)

// Solid rod on bottom, internal threads on top (flip around x-axis after printing to pair with RodStart)
module RodEnd(diameter, height, thread_len=0, thread_diam=0, thread_pitch=0)

// Internal threads on bottom, external threads on top
module RodExtender(diameter, height, thread_len=0, thread_diam=0, thread_pitch=0)

These modules allow you to insert non-threaded holes or specialized shapes into your geometry. Rotation vectors are applied first, followed by position translation, starting from a position upward from the z-axis at z=0.

// Standard clearance hole
module ClearanceHole(diameter, height, position=[0,0,0], rotation=[0,0,0], tolerance=0.4)

// Clearance hole with a recessed bolt hole (defaults fit standard metric bolts)
module RecessedClearanceHole(diameter, height, position=[0,0,0], rotation=[0,0,0], recessed_diam=-1, recessed_height=-1, tolerance=0.4)

// Countersunk clearance hole (countersunk side is on the bottom by default)
module CountersunkClearanceHole(diameter, height, position=[0,0,0], rotation=[0,0,0], sinkdiam=0, sinkangle=45, tolerance=0.4)

// Phillips tip shaped hole
module PhillipsTip(width=7, thickness=0, straightdepth=0, position=[0,0,0], rotation=[0,0,0])

Use these modules to generate complete, standard-sized metric hardware components.

// Metric hex bolt
module MetricBolt(diameter, length, tolerance=0.4)

// Metric countersunk (flat) bolt with hex key drive (length includes head)
module MetricCountersunkBolt(diameter, length, tolerance=0.4)

// Metric wood screw
module MetricWoodScrew(diameter, length, tolerance=0.4)

// Metric hex nut
module MetricNut(diameter, thickness=0, tolerance=0.4)

// Metric washer for a nominal thread diameter
module MetricWasher(diameter)

// A set of matching metric bolts, nuts, and washers
module MetricBoltSet(diameter, length, quantity=1)