When building woodworking projects. problems can arise when component parts stray from the usual square and parallel cuts. When projects or parts of projects veer into the world of angles and curves a carefully drawn full-scale layout will help navigate the project to an easy, successful, conclusion.
Tools you need for making full-sized drawings include both small and large, reliable carpenters squares, a straight edge, an angle gauge, and various length woodworking rulers. For curved or round parts a compass and beam compass will be needed.
When making a full-scale layout the first and most important rule is generating a precise drawing that accurately represents the elements of the part or parts and their relationship to each other. That means angles, lengths, widths, finished heights, curves, etc., must be drawn precisely. That’s because you will rely on the drawing to determine information about a part that’s not known.
Here’s an easy example. Say you want to determine the length of table legs that are splayed 7°. You know the leg is 1¾” square, the finished table height is 30½” and the angle is 7°. To determine the leg length, draw a horizontal line representing a floor, draw a parallel line 30½” representing the finished table height, draw another parallel line 1” down from the top to indicate the thickness of the tabletop. Now you can find the accurate length of the leg. Reference the floor line (or the line of the underside of the top) then draw a precise, 7° angle line connecting the two. The top and bottom of the leg will automatically have the 7° angle. Now it’s easy to measure the leg length.
Likewise, you can use you’re layout to determine the length of the tables aprons and stretchers. To determine these dimensions, layout the planned setback of the legs from the table ends. Now add a line representing the width of the apron that extends just long enough to strike a 90° angle between bottom apron line and the intersection top of the leg and top of the apron where they meet at the tabletop bottom line. Now you can quickly calculate the apron length by adding the leg setback and leg thickness and multiplying that number by two. This accounts for both ends of the table. Next carefully measure the distance between the 90° line at the apron bottom and where meets the table legs and double it to account for both apron ends. Now some quick math will tell you actual length of the aprons.
The beauty of working with a full-scale layout goes beyond the ability to calculate part sizes. With the part drawn full-size, you can compare the actual part you make to the drawing. Just lay it on the drawing to check it. Further, you can position mating parts on your drawing to make sure the relationship conforms to the drawing.
When working with parts that are curved, full-scale layouts can be used to make a pattern from which actual parts will be shaped. Take, for example, a pair of Danish Modern folding chairs I recently made. The full-scale patterns were provided as part of a project article that appeared in Popular Woodworking Magazine. I took the layouts to an office supply store and had them enlarged to their exact full size. From these enlargements I was able to make an exact pattern of the parts outside shape. It could then be used to make the parts using my patterns along with straight router bit equipped with a top mounted bearing. All I had to do trace the pattern on my parts, rough cut the parts close to the pattern line then lightly nail the pattern to part for final shaping on the router table.
These full-scale drawings also provided precise locations for routing mortises while the parts were captured in a fixture based on patterns.
Full-scale layouts can resolve many problems building woodworking projects. They are a must when working with complex angles or curves. But often, even a quick layout will save you time and provide positive answers to relatively simple questions. One common example is placement of metal drawer slides inside a cabinet and on the drawer side. By simply drawing the cabinet interior height, you can place the cabinet member position then determine where the drawer side member goes and make sure of the entire drawer box is properly placed inside the cabinet.
About the Author: Steve Shanesy was editor and publisher of Popular Woodworking magazine for 19 years. Prior to that he spent 15 years working in and managing high-end furniture and cabinet shops in Los Angeles and Cincinnati.