# Printing binding posts with the Chicago Screw Generator

> two-part screw posts for straps, books, and stacked assemblies

Chicago screws (binding posts) are the fastener for anything stacked and swappable: leather straps, sample swatch books, restaurant menu covers, scrapbook bindings, and laser-cut layer assemblies. One half is a barrel with an internal thread, the other a screw that threads into it, and both ends finish with a clean flat head.

The printed version has a trick metal ones do not: total grip-length freedom. Set the male and female lengths to exactly your stack thickness, instead of hunting for the nearest standard post and shimming the difference.

## What you need

- Any FDM 3D printer; 0.12-0.16 mm layers recommended for the threads
- PETG for working posts that get opened and closed often; PLA is fine for set-and-forget
- The actual stack (strap, book, layers) to measure its compressed thickness

## Step 1 - Match the stack



Open the tool and measure your stack. Set **Male Length** and **Female Length** so the two halves meet inside it: combined grip equals the stack thickness, with the thread fully engaged. Set **Shank Diameter** to suit the punched hole (5 mm is a common leatherwork size) and the **Female Outer Diameter** for the barrel wall around it.

## Step 2 - Heads and thread fit



- **Head Diameter** and **Head Height** shape both finished faces; wider heads spread load on soft leather and fabric.
- **Clearance** is the printed gap between the mating threads; increase it slightly if your printer over-extrudes.
- **Thread Pitch** and **Thread Depth Factor** tune the thread itself; the defaults print reliably on a 0.4 mm nozzle, with coarser pitch being more forgiving.

## Step 3 - Export



Download **STL** or **3MF**; both halves export together, ready to slice.

## 3D Printing

### Print the pair



1. Print both halves heads-down as exported so the threads build as clean vertical helixes.
2. Fine layers (0.12-0.16 mm), 4 perimeters, 25 percent or more infill.
3. Thread the pair together a few times off the printer to burnish the fit before installing.
4. If the fit binds, bump Clearance up 0.05 mm and reprint the female half only.
5. For frequently opened posts, a tiny dab of dry PTFE lube keeps printed threads smooth for hundreds of cycles.

## Make it yours

- Bind laser-cut leatherette swatch books with one post through the corner.
- Make adjustable printed-and-cut belt or camera strap prototypes before committing to metal hardware.
- Post-bind a guest book or recipe binder so pages can be added forever.
- Join layered laser-cut signs with visible posts as a deliberate industrial detail.
- Print heads in accent colors to color-code menu covers by section.
- Oversize the head into a flat disc and you have a printed rivet for fabric banners.
- Pair with the Dowel Pins Generator for assemblies that need both fixed pivots and removable posts.

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Open the 3D Print Chicago Screw Generator: https://www.mylasertools.com/3d-chicago-screw-generator
Read online: https://www.mylasertools.com/learn/guides/3d-chicago-screw-generator