Working without numbers
Any woodworker will tell you that one of the hallmarks of fine woodworking is tight joinery. The key to gap-free joints is the ability to make precise cuts, and accurate layout is where it all begins. Many of the tools in my shop have either metric or imperial scales, but for the greatest accuracy I don’t rely on graduations at all. Whenever a distance is converted into numbers, an opportunity for error is introduced – numbers may be misread or transposed and scales on tools may be calibrated differently.
Some Basic Tools
Measuring tools that can be used include combination squares, marking gauges, calipers, dividers, story sticks and bar gauges (also known as pinch sticks).
Reinvent the Wheel
Though many tools work well when dealing with small distances, a marking gauge is perfect if you want to scribe a line on the workpiece. A marking gauge with a cutting wheel works best.
What Tools Do I Use?
Although there are a few specific tools for direct measurement, it is not imperative that you have them. Most woodworkers probably already have most of the necessary tools in their shop.
When transferring relatively short depths, such as a mortise’s depth or offset from a leg to apron, I prefer to use a small combination square. A pair of calipers will also do the same thing. When possible, I prefer to use the end of the two jaws to get the measurement, but if the jaws are too large, I use the depth rod at the butt end of the caliper.
If I need to precisely scribe another piece with that measurement, I use a wheel marking gauge instead. The marking gauge’s built-in cutter eliminates the need for a separate tool as with a combination square. With a marking gauge, it is easier to scribe an accurate mark because the cutter is integral.
A super-accurate way to divide a board into equal segments is to use a pair of dividers. Adjust the span of the dividers until you can walk the dividers across the board and the points fall on each edge. The same technique can be used to divide a circle or arc into equal segments. A slight modification to this technique will help you lay out evenly-spaced dovetails too. (More on that later.) M Power Tools Ltd. makes a tool called Point-2-Point that makes dividing a length into equal parts easier.
When working with multiple identical parts, you can easily transfer your layout from one to the others – simply align their edges and carry the line(s) across with a square. Often, it is helpful to clamp the parts together to prevent them from shifting.
When transferring a length from one part to another, the surest way is to hold them together and mark right off the part’s end. If that’s impractical or too awkward, use a story stick or bar gauge (pinch sticks). A story stick is simply a straight length of wood longer than the distance you need to measure. Line up one end of the story stick with one reference surface and use a sharp pencil or knife to mark the opposite reference surface. A story stick may contain a single dimension or every dimension needed to recreate a project.
Bar gauges are a little different. A bar gauge consists of two parts, each shorter than the distance you wish to measure (or longer if you are taking an outside measurement), and some sort of clamp (such as your fingers or a spring clamp) to hold them together. In use, the bars are extended until they meet the registration surfaces and are then secured together. The advantage of bar gauges is positive registration.
(Almost) Automatic Joinery
Careful layout and cutting have always been keys to quality joinery but two new tools from Bridge City Tool Works help to simplify the process. Used in conjunction with any tool able to cut a clean, repeatable kerf such as a table saw, the Kerfmaker and Tenonmaker are used to cut cross-lap joints and tenons, respectively, with a high level of repeatable accuracy. Their use is simple and intuitive. Before the first use, they need to be calibrated to the blade they will be used with and the simple procedure is described in the manual.
To use the Kerfmaker, first gauge the thickness of stock that will fit into the housed joint and lock the setting. Note that when gauging stock you can control the tightness of the joint by squeezing tightly or applying only light pressure. With the gauge set, line up the first cut and position a stop block with the Kerfmaker between it and the workpiece, taking note of which way the offset is positioned and which way the stock will move for the second cut. Make the first cut, then flip the Kerfmaker and slide over your workpiece to make the second cut. Finally, waste away the material between the two cuts.
Used with a tenoning jig and a tablesaw, the Tenonmaker is set to the length and width of mortise (one at a time) and used as a flip stop like the Kerfmaker. Start with your mortise already cut and ends squared, then use the Tenonmaker to gauge the width of the mortise. Clamp your tenon stock in a tenoning jig and align it for the first cut. Set the Tenonmaker between the tenoning jig and a stop block and cut the first tenon cheek. Flip the Tenonmaker and slide the tenoning jig over, then cut the second cheek. Then set the Tenonmaker to the length of the mortise and make the top and bottom cuts. Finally, make the shoulder cuts to complete the tenon. The Tenonmaker can also be used with a bandsaw though the cheeks won’t be as smooth. Of course, if the tenons are blind, this isn’t so much of an issue. Also a tenoning jig is not needed and this has become my preferred method for blind mortise and tenon joints.
No Numbers – In Practice
1. For demonstration, I built an inset drawer using the tools and techniques outlined in this article. With the materials surfaced, I needed to cut the sides and drawer front to width. I aligned one edge of the drawer stock with the top of the drawer opening and made a mark at the bottom of the opening.
2. At the tablesaw, I positioned the fence so that the blade aligned with the mark and ripped the drawer sides, front and back to width.
3. To determine the lengths of the front and back, I used a bar gauge and transferred that measurement to the workpiece.
4. To mark the sides, I slid them into the drawer opening until they contacted the back and marked accordingly at the front, remembering to factor in the joinery. To mill the grooves for the 1/4″ plywood drawer bottoms, I first set the blade height. Since the drawer sides are about 3/4″ thick, I set the blade height to about 1/4″, using a scrap of 1/4″ plywood as a guide.
5. Then I set the fence 1/4″ away using the scrap as a spacer.
7. To use the Kerfmaker, I positioned it against the body of the fence and clamped a stop block on the other side. I made the first cut, then unlocked the fence and flipped the Kerfmaker to locate the fence for the second cut.
9. Then, to evenly lay out the spacing of the tails, I first reset my marking gauge to the width I wanted between the tails and made a mark referenced off each edge. Then I adjusted my dividers so that they would span from the edge of the board to the opposite marking gauge line in three increments (three because I wanted three tails).
10. Then I marked from the other edge, leaving me with even spacing for tails across the board.
11. Finally, I used a square to extend the marks across the end grain and cut the tails.
12. Then I positioned the tail board over the pin board and used a marking knife to lay out the pin cuts. I cut the pins and checked the fit.
Once the drawer was dry-fit, I used my bar gauge to determine the length and width of the drawer bottom. I cut the bottom to size and did a final dry-run before applying glue. After clamping up, I ensured that the drawer was square by comparing diagonals, once again using a bar gauge.
Chris Wong - [email protected]
Chris is a sculptural woodworker and instructor.
Thanks for this info ! But, I don’t understand how you find the centre of stock with 2 dividers. Could you give me another hint?
You can use one pair of dividers to find the middle of a board by placing one point on an edge, walking the next leg towards the other edge, then pivoting off that leg and ensuring the last next point falls on the other edge. For accuracy, it’s important that all three points are in a straight line, but that line does not need to be perpendicular to the edge!
For round stock, the same trick works to find the exact centre but you must follow a diameter line. You can draw this using a 45 degree square to bisect a 90 degree square registering against the outside of the circle.