Parametric Butt Hinge

This is a two piece parametric butt hinge designed in OpenSCAD, offering a wide range of parameters for customization. The hinge is designed to be printed in one step, but the individual leaves can be printed independently if desired.

The two pieces are comprised of a male and female leaf, including a customizable pin which is fused to the female leaf by default. The pin may be omitted from the female leaf in the event that an external pin is to be used.

Note:
There may be a rendering artifact that appears in the Customizer, when enabling knuckle gussets. This is either a browser issue or an OpenSCAD rendering artifact, and should not affect the physical model that you download and print. Also, if you download the OpenSCAD source file, it should render without any artifacts once loaded in the latest version of the OpenSCAD editor.

Parameter Overview

Component Options

• Male Leaf Enabled
  Print the male leaf if true, otherwise omit it from the print.

• Female Leaf Enabled
  Print the female leaf if true, otherwise omit it from the print.

• Leaf Fillet Enabled
  Enable filleted leaf corners. Aside from aesthetic value, filleted corners can help with warping to a degree.

• Knuckle Gusset Enabled
  Toggle knuckle gussets on or off. Knuckle gussets add strength to the transition between the knuckles and the leaves. The length of the knuckle gussets is equal to the fastener margin size, so that the gussets will never overlap any fastener holes.

• Pin Enabled
  By default, the hinge is designed to be printed in one go, with a hinge pin fused to the female leaf. However, there may be applications where one may prefer to use an external pin. For instance, in the case where a metal pin is prefered for the sake of strength. In applications where an external pin is to be used, the pin may be omitted from the female leaf, by setting "Pin Enabled" to false.

• Pin Auto Size Enabled
  If true, this will set the pin diameter to the leaf gauge.
  If false, the pin diameter may be specified by the "Pin Diameter" parameter.

• Fasteners Enabled
  Include fastener holes if true.
  If false, leave the leaves free of fastener holes.

• Resolution
  The geometric model resolution. Corresponds to the number of sides used to construct cylindrical parts of the model, like the knuckle joint segments, and the leaf fillets.
  For example, a "Resolution" of 8, would specify cylindrical component elements to be constructed from 8 sides. a "Resolution" of 32 would result in 32 sided cylindrical component elements, and so forth.
  For a smooth model, a "Resolution" of 64 and above is recommended. By default "Resolution" is set to 128.

• Component Color
  This is used purely to color the model in the Thingiverse Customizer. It should not affect the color of the model, printed from a color printer.

Hinge Parameters:

• Hinge Width
  The width in millimeters, of the entire hinge, from the outer edge of the left leaf, to the outer edge of the right leaf.

• Leaf Height
  The height in millimeters, of the hinge along the knuckle joint axis.

• Leaf Gauge
  Defines the thickness in millimeters, of the leaves and the radius of the knuckle joint.

• Component Clearance
  The inter-component gap in millimeters.
  Recommended values range from 0.3mm for a tight fit, to 0.5mm for easy-er manipulation after printing. Clearance values of 0.3 or below can be challenging to print. I have succeeded in printing a few of these hinges with component clearances of 0.2mm and 0.25mm. However, quite often, sub 0.3mm clearance results in a locked up knuckle joint, where the leaves break before the hinge loosens up. A clearance of 0.4 or greater should release without to much trouble.
  Note: The more knuckle segments there are, the greater the initial joint friction strait off the build plate. So for higher knuckle counts (7 or greater), component clearances of 0.4 or higher, may be required.
  If the knuckle joint is not moving free at 0.4mm or higher, try re-printing slower at a higher resolution, in particular z resolution. Lower temperatures can help as well.
  For PLA, a resolution of x=0.3, y=0.3, and z=0.15, at a speed of 6mm/s or less, with temperature 190 degrees C, seems to support a component clearances of 0.3mm to 0.4mm relatively well.
  All of the sample STL files in the "Thing Files" section, are set to 0.3mm component clearance.

• Knuckle Count
  The number of knuckle segments in the knuckle joint.
  This number should be an odd number.
  For most applications, a knuckle count of to 3 or 5 should suffice. However, higher knuckle counts can offer increases in strength relative to gauge size and hinge dimensions.

• Pin Diameter
  Manually specified pin diameter. This value is only used by the model, if "Pin Auto Size Enabled" is set to false.
  If "Pin Auto Size Enabled" is true, then the pin diameter is automatically set to the leaf gauge size.

Fastener Hole Parameters:

• Fastener Head Type
  Can be set to either counterbore for pan head machine screws, or countersunk for flat countersunk screws.
  The chamfer angle for flat countersunk may be adjusted by varying the other fastener hole parameters. For instance, a thread diameter of 3mm (e.g. M3 machine screws), a head diameter of 9mm, and a countersink depth of 3mm, with give a chamfer angle of 45 degrees.

• Counter Sink Depth
  The depth below the surface of the leaves to sink the fastener heads.
  For M3 machine screws 2.5 to 2.6 is usually enough.
  If the fastener holes are not countersunk, then there will be mechanical interference between the fastener heads the the opposing leaves when the hinge is closed.

• Fastener Thread Diameter
  The diameter of the threaded portion of the fastener hole.
  This can be made smaller than the fastener thread in order to support self tapping screws, or larger to give machine screws enough room to pass through.

• Fastener Head Diameter
  The diameter of the counter sunk head portion of the fastener hole.
  Usually a good idea to make this diameter 0.5mm to 1.0mm larger than the actual fastener head diameter. For M3 machine screws, which typically have 6mm diameter pan heads, an "Fastener Head Diameter" of 7mm works well.

• Fastener Count
  The number of fastener holes per leaf. The total number of fastener holes in the entire hinge will be "2 x Fastener Count".
  Fastener holes are arranged in one or two columns along the height of the hinge, as specified by "Fastener Column Count".

• Fastener Column Count
  Specify whether to arrange the fastener holes on a leaf, in one or two columns.

• Fastener Margin
  The distance from the circumference of the fastener head, to the edge of the leaf.
  Values between 3mm and 5mm are recommended for small to medium gauge hinges.