How to 3D Print a Shoe Last with a Working Alpha Joint

In this Shoe Last Maker Tutorial, you’ll learn how to 3D print a shoe last with a working alpha hinge. The tutorial starts with the hinge design process within the Shoe Last Maker plugin for Rhinoceros 3D. If you prefer to skip the design work, you can get models of hinged shoe lasts from podohub.com.

Designing a Shoe Last Hinge for 3D Printing

To design a shoe last alpha hinge that can be 3D printed, press the print button on the side panel. A form will come up with a variety of options. Some of the more important settings are pointed out below. First though is an image showing some key alpha hinge features.

3D Printing a Shoe Last with a Working Alpha Hinge Diag

3D Print Shoe Last Alpha Hinge Settings 3

  • Metal/Plastic Spring: This toggle adjusts various settings depending on whether you plan on using a metal or plastic spring. The plastic spring is advantageous because it can be 3D printed, meaning you don’t need to source the metal spring.
  • Spring Stretch: This is the amount of stretch the plastic elliptical spring is subject to when the hinge is in the closed position. Increasing this number will shorten the distance between the pivot holes on the elliptical spring, forcing it to be in a more stretched position. A more stretched position means a tighter alpha hinge.
  • Pivot and Spring Pin Hole Diameters: These setting determine the diameters of the holes passing through the elliptical spring and the corresponding holes through the shoe last walls. The default settings are for using #8 wood screws (standard size for deck screws). The advantage of wood screws is that they are readily available. The disadvantage is that the tightness of the hinge is limited. For a tighter alpha hinge using the same settings, a 1/8″ dowel pin can be used. For an even tighter hinge, the settings can be adjusted to work with a 1/4″ dowel pin.
  • Pipe Thimble: Thimbles are important if you plan to hold the shoe last on a lasting pin as otherwise the plastic can crack. Rather than sourcing shoe last thimbles, a simple 1/2″ copper pipe can work. The Pipe Thimble toggle will ensure the appropriate design work for this.
  • Percent Length Along Dorsal Profile for Cut Position: Depending on the size and type of shoe last, you may want to move the alpha cut position forwards or backwards. A positive number for this setting moves the cut position forward along the dorsal profile and vice versa.
  • Disc Wiggle Room: This is the gap between the discs and the cavity walls in which they sit. The same gap is applied to the elliptical spring and its cavity walls. Higher precision 3D printers can get by with less wiggle room.
  • When you are satisfied with the settings, press the ‘Go’ button and the hinge will be designed. By default, an option to orient the parts for 3D printing is turned on, the results of which are shown below.

    Shoe Last with Alpha Hinge oriented for 3D Printing

    3D Printing and Assembling Your Shoe Last

    Some tips on 3D printing and assembling your shoe last are included in the video tutorial at the top of this page. For written details, please refer to this page on Podohub.com: How to 3D Print your own Shoe Lasts.

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