Maker’s Note-subplot: Common Mistakes in Molding for Wooden Furniture

by Shu-Yu Liu

Recently, our studio has been working on a lot of woodwork, partially for our own use at the studio, and because I like to try new ways to build things. Also, the woodwork theme increases the views for our YouTube channels.

The following are two types of problems that you should be noted. The first are the mistakes that are easy to solve. The others are those that you keep making them, even though you have learned lessons from again and again.

Type 1: Specs for the bevel-cut board

Some elegant and advanced designs usually require boards with bevel cuts, such as French cleat, inclined cabinet feet, and trapezoid structure for lumber storage carts. Take the 45-degree edge as an example. If you want to cut out a parallelogram, there is no problem with using a table saw fence positioned at wherever you want it to be. When cutting a trapezoid; however, a saw blade can only lean toward the opposite side of the saw fence. Therefore, the fence is not positioned at either the short side or the long side of the trapezoid, which forms a counterintuitive measurement consisting of length of the short side plus the thickness of the board. As shown in the graph below, the saw fence is pushed against the long side of the trapezoid, while the surface for cutting is measured based on short side, which leads to the strange measurement.

Type 1: Specs for the plywood never add up

If you are using plywood for decoration, it is expected that the thickness of the plywood varies from shop to shop, and even sometimes the boards from the same shop and the same shipment can come in different measurements. It is best that, after drafting, you check the thickness of the wood before cutting. If there is a difference of more than 0.5mm, it is better to modify the specs using 3D simulation to have the new size for cutting!

Type 1: Assembly planning

3D drawing can trick people into thinking that the process is simplified, yet when you actually start assembling, you will find that there are too many factors to take into account: whether the fixture holds the object steadily or the structure space is too small to wield a screwdriver. One thing I run into most often is the positioning of screws and the wrong order of operation.

With the wrong order, the screws may not be able to hold the structures as intended.

These issues are basically the same, all arising from not considering the order of operation when you are drafting. A 3D drawing merely shows design outcome for your reference, but the process during operation still requires much thinking. In addition to the design drawing and a cut list, it is recommended to list out every detail in steps for your operation!

Type 2: Rounding the number? Rounding up? Rounding down?

Although a structure may be designed with only round numbers, it is likely that there are decimals, arising from cutting bevels or others reasons causing changes in the cutting specs or positioning. However, most electric tools, such as a circular saw, have only the accuracy down to only 1mm, which allows me to cut the objects on the basis of only 0.5mm. For this reason, I need to decide whether to round up or down the number, when I put the number from computer simulation into practice. It is suggested that you think about which calculation could give you the minimum difference possible!

Type 2: Expected difference

Even beginners know there will be differences in specs between drawing and the end product. In woodworking, the differences can increase depending on the complexity and the specs variation. For 3D-printing, especially, it is safer to leave a difference more than 0.5mm, which all depend on the nature of the object and the technique of the operators.

The above are some of the tips I have learned from doing woodworking for more than 1 year. Should you have any suggestions and comments on the solutions to our Type 2 mistakes or any problems you run into during operation, please feel free to leave comments on our Facebook page or YouTube channel!