Introduction

This is a book about making a real, physical thing with your own hands and a machine, starting from knowing nothing at all.

The thing we are going to make is small and a little bit silly, and that is on purpose. It is a portable lemon squeezer: a pocket-sized tool you can drop in a lunch box, pull out at your desk or on a picnic, and use to squeeze fresh lemon over your food without crushing the fruit in your bare hand or carrying a bulky kitchen gadget. By the end of the book you will have designed one, printed it, tested it on an actual lemon, found everything wrong with your first attempt, and printed a better one.

The squeezer is the excuse. The real subject is 3D printing, and more broadly, the loop that every maker lives in: imagine a thing, design it, make it, test it against reality, learn what reality says, and try again. That loop is the same whether you are printing a lemon squeezer, a phone stand, or a replacement knob for a washing machine that the manufacturer stopped selling in 2009.

Who this is for

You, if you have never used a 3D printer and are not sure you even understand what one does. No engineering, no CAD, no maker background is assumed. If you have used a printer before, the early chapters will move quickly for you, and you can skip to the design and project parts.

We assume you are curious and willing to get your hands a little dirty (sometimes literally, with sticky lemon juice). We do not assume you already own a printer. One of the first things this book does is help you decide whether to buy one, and what to do if you would rather not.

What you will be able to do by the end

  • Explain how a 3D printer turns a digital model into a solid object, in plain words.
  • Choose a beginner printer and material, or use a print service or a library makerspace instead of buying anything.
  • Print real, useful objects and recognize and fix the common ways prints fail.
  • Design your own simple parts, both by dragging shapes around on screen and, if you like, by describing them in code.
  • Design, print, and improve a portable lemon squeezer, and understand the honest trade-offs of using a printed object with food.

How the book is built

We go in phases, smallest first. You do not jump straight to the squeezer, the same way you would not bake a wedding cake as your first time touching an oven. The order is deliberate:

  1. Welcome to 3D printing. What the machine is, how to get one (or borrow one), what materials exist, and how to do your very first print.
  2. Learn by doing. A pile of small, genuinely useful prints, plus the two skills that separate a frustrated beginner from a happy one: slicing and troubleshooting.
  3. Designing your own things. Going from printing other people's designs to making your own, first by dragging shapes, then optionally by writing a few lines of code.
  4. The project. The portable lemon squeezer, start to finish: the brief, how squeezers actually work, designing yours, the food-safety questions, printing and testing it, and iterating to a version you are happy with.
  5. Reference and next steps. A glossary, and a ladder of follow-on projects so this is the start of a hobby, not the end of a book.

A few honest words before we start

3D printing is genuinely fun, and it is also fiddly. Your first print might fail. Your fifth might fail. This is normal, it is not a sign you are bad at it, and a big part of this book is teaching you to read a failed print like a doctor reads an x-ray. We will be honest throughout: about which materials are safe near food, about what a cheap printer can and cannot do, and about when the answer is "buy the five-dollar one from a shop instead." Curiosity, not perfection, is the point.

👉 First, let us talk about how to read this book and what you will want on hand.