What woodworker doesn’t like a good challenge, something to expand the mind, teach a new skill, build new muscle memory? Well, if you’re like me and savor such a break in the routine of making sawdust, then I’ve got a good one for you. Or, I should say, George Walker and Jim Tolpin do. The most recent of their series of books featuring the use of Euclidean geometry in design, Euclid’s Door, does just that. This slim volume gives step-by-step guides for creating seven wooden marking tools that will find a useful place in any woodshop, whether hand tool, machine-oriented, or hybrid.

Perhaps you may question whether wooden tools can be as accurate as your machinist’s square or expensive adjustable square. A read-through of Euclid’s Door will quickly demonstrate that not only can Euclidean rules lay out accurate lines and angles but that the effective means for proving their accuracy in use are at hand. All this is achieved with little more than a straightedge and compass, along with some simply built appliances. The rest is up to you, providing a good test of your hand tool skills or, if you’re new to that work, a chance to develop them.

The book introduces seven projects for tools you’ll put to good use. Each of them, which make up good weekend projects, builds on skills developed, and tools built, in previous projects. Thus, the projects occur in a planned sequence that you’ll follow from beginning to the end of the book. By the time you’ve finished, you’ll have strengthened your grasp of basic rules of geometry and how it can be applied to solve simple design problems in the shop. And, you’ll have enhanced your hand tool skills by the chance to make the fine adjustments that will ensure your new tools are dead accurate.

The opening chapter gives useful background that will underlie your work on the projects. You’ll get a reminder about the methods by which logs are sawn into lumber, leading to the advice that straight grain rift or quartersawn lumber will yield the most stable stock. The authors advise preparation of half a dozen boards, planed to remove saw marks and reveal fresh grain, then acclimated for at least a few days and even longer if possible so internal tensions are released before you begin precision work. Additional guides explain the tools you’ll need for the builds and appliances you’ll want to construct to aid in building your new tools.

The first project is to construct a set of straightedges of differing lengths. This construction, which requires the most basic geometric form—a line—uses two boards, each planed smooth and straight on one edge, then “proofed” by pairing the planed edges of the boards and inspecting them for daylight in gaps. If you’ve started with longish boards, they can then be crosscut into shorter segments to create straightedges of different lengths. You may then elect to drill holes for hanging them and shaping to the opposing edges to embellish or distinguish them from the business edge.

A set of winding sticks make up the second project. Here the geometric challenge is to create parallel edges. The bottom edge of each of the two sticks is, in effect, a straightedge like you just created. But for the winding sticks to be effective, the top edges must be exactly parallel to the bottom edges. Walker and Tolpin show Euclid’s method to easily lay out parallel lines, then walk you through the method for proving the accuracy of your planing. They like to inlay a strip of contrasting color wood at the top of the rear stick so judgments of twist in the boards you’re testing can be easily seen. They also show how you can make trestles, as Roubo did, to lift your sticks above the wood you’re proving.

Try squares are the next project. Here the goal is to create tools that accurately measure right angles. The squares will be useful to measure the squareness of board edges, the accuracy of carcass corners, and the ends of boards that will be joined in furniture. Euclid accurately drew right angle by creating a straight line and a circle, and you can follow his lead with a compass and your straightedge. The authors show how you can then build the blade and the handle, which is attached by a bridle joint. Though the authors only demonstrate building the basic, accurate tool, you have the creative opportunity to add refinements such as wood of contrasting colors or shaping the ends of the handle and blade for decorate effect.

Marking squares are used to mark lines at a 90° angle for crosscutting. They consist of blades of differing lengths, if you’re making several, attached to a handle set at 90° to the blade. The blade preparation uses the same skills as building the straightedge. The 90° angle is determined by one of several methods by using a compass. As in each of the projects, the authors offer valuable instruction on how to dial in perfect accuracy using hand planes.

The next project is to create triangles that use angles other than 45°. The authors show how you can create 30° and 60° angles. The resulting tools can then be laid on a shooting board to enable shooting angles other than 45° or for proving the accuracy of these angles in joinery.

A set of miter squares follows. These make use of one of the techniques for creating 45°, 30°, and 60° angles learned in building the triangles. The resulting tools will be valuable in checking edges for squareness. They’re the most complicated of the projects and thus a good test of what you’ve learned in building the earlier tools.

The final tool is a panel gauge, or maybe a set of them, that you’d use to mark lines for ripping a board to the desired width or perhaps to lay out mortises. The project includes creating a straight beam, chopping a mortise in the fence, and building a wedge to hold the assembly in tight alignment during use. As with all the projects, this is an opportunity to exercise your creative juices to embellish the final product.

This book is sure to be a big hit with hand tool experts who are looking for ways to exercise their talents to create useful items. And woodworkers seeking to enhance their hand tool skills will find detailed advice valuable in executing accurate work. But even if you have no current plans to make any of these projects, it’s a good read for anyone up for a mental challenge and a desire to learn some basic geometric tricks. As for me, I’m adding this book to my collection, and I look forward to some enjoyable time in the shop building tools that will help me do my best work.

J. Norman Reid is a woodworker, writer, photographer and woodworking instructor living in Virginia's Blue Ridge Mountains with his wife, a woodshop full of power and hand tools and two cats who think they are cabinetmaker's assistants. He is the author of Choosing and Using Handplanes: All You Need to Know to Get Started Planing by Hand, and co-owner of Shenandoah Tool Works. He can be reached by email at jnreid45@gmail.com.