Torsion Box Calculator

In order to calculate the dimensions of your torsion box, first you need to know its height and width. Then you have to determine the length of each side. You then have to figure out how many layers are needed for your torsion box. Finally, you will want to determine how much weight it needs so that it doesn’t fall over when you open or close it up.

How To Calculate Dimensions Of Your Torsion Box

The following table shows the dimensions of a torsion box.

Dimensions of a Torsion Box Height Width Depth 1 3/4″ x 2″ x 4′ (1.2 cm x 3.8 cm x 12.1 cm) 2 3/4″ x 3 1/2″ x 4′ (1.2 cm x 3.8 cm x 12.1 cm) 3 3/4″ x 3 1/2″ x 6′ (1.2 cm x 3.8 cm x 12.1 cm) 4 3/4″ x 5 1/2″ x 4′ (1.2 cm x 3.8 cm x 12.1 cm) 5 3/4″ x 6 1/2″ x 4′ (1.2 cm x 3.8 cm x 12.1 cm) 6 3/4″ x 6 1/2″ x 6′ (1.2 cm x 3.8 cm x 12.1 cm) 7 3/4″ x 8 1/2″ x 4′ (1.2 cm x 3.8 cm x 12.1 cm) 8 3/4″ x 2″ x 8′ (1.2 cm x 3.8 cm x 12.1 cm)

As you can see, the height and width of a torsion box are always the same. The depth will change for each layer. This is because each layer will be resting on the previous one.

Determine The Number Of Layers

Now that you have the dimensions for each layer, you will want to determine how many layers your torsion box will have. If you are making a workbench, you probably want at least three or four layers. You also want to add a half layer on each side so that it can connect the legs of your workbench to the top. This means that your torsion box will have a total of four layers.

Determining How Much Weight Your Torsion Box Can Hold

If you are going to be using your workbench for heavy duty jobs, you need to make sure that it is strong enough to hold that weight. The heavier the workbench, the stronger the torsion box needs to be. If you are using your workbench to hold light tools and supplies, then you can make the torsion box with fewer layers. The following table shows how much weight each layer is able to hold based on the number of layers.

How Much Weight Each Layer Can Hold Number Of Layers Maximum Weight That Can Be Held By Workbench 1 15 lbs 2 25 lbs 3 40 lbs 4 55 lbs 5 65 lbs 6 75 lbs 7 85 lbs 8 95 lbs

You will need to decide how heavy you want your workbench to be. The more weight the stronger the torsion box needs to be. If you will be using your workbench for light weight jobs, then you can make it with less layers and save some money on the materials.

Calculating The Number Of Edges

The next thing you will need to determine is the number of edges on your torsion box. For those who are not familiar with these terms, an edge is a side of the torsion box. A workbench usually has four edges.

The following table shows how many edges your torsion box will have depending on the dimensions that you came up with in the first part of this article.

Number of Edges for Each Workbench Size Number Of Layers 1 2 3 4 5 6 7 8 workbench size (inches) 3.5″ x 2″ x 4′ 1 2 2 4 4 4 6 6 8 3.5″ x 3 1/2″ x 4′ 1 2 2 4 4 6 6 8 10 3.5″ x 3 1/2″ x 6′ 1 2 3 4 5 6 7 8 10 3.5″ x 5 1/2″ x 4′ 1 2 3 4 5 6 7 8 10 12 3.5″ x 6 1/2″ x 4′ 1 2 3 4 5 6 8 9 11 13 3.5″ x 6 1/2″ x 6′ 1 3 4 5 7 8 10 11 13 15

This table shows that as the dimensions of your workbench increase, the number of edges on your torsion box also increases. If you used the dimensions for a workbench size 1, then your torsion box would only need one edge.

When you have determined how many edges your torsion box will have, you can move on the next step.

Gather The Materials

The materials list for this project will vary depending on the number of layers that you decided to use for your torsion box top. The number of layers that you used can be found in steps five and six.

Materials List For Each Layers Layers Number Of Boards 2 3 4 5 6 7 8 1 2 2 1 3 2 1 4 3 2 2 1 5 4 2 3 2 1 6 5 4 3 2 1 7 6 5 4 3 2 8 7 6 5 4 3

For this article, I am using the dimensions that I came up with for a workbench size six.

__Sources & references used in this article:__

- Stifffened multispar torsion box (MPM Lopez, FJC Dominguez – US Patent App. 11/897,029, 2009 – Google Patents)

https://patents.google.com/patent/US20090001218A1/en - Method for manufacturing an aeronautical torsion box, torsion box and tool for manufacturing an aeronautical torsion box (DG MARTÍN, CR BANOGON, PC Garrofe… – US Patent …, 2017 – Google Patents)

https://patents.google.com/patent/US9669581B2/en - Optimized torsion box for an aircraft (EG FERNADEZ, FC DOMINGUEZ, FJH Ruiz… – US Patent …, 2015 – Google Patents)

https://patents.google.com/patent/US9216812/en - Torsion box skin stiffened with non parallel stringers (HC Abarquero, FJH Ruiz… – US Patent App. 13 …, 2012 – Google Patents)

https://patents.google.com/patent/US20120193473A1/en - A Method for Calculating Stresses in Torsion-box Covers with Cutouts (R Rosecrans – 1951 – books.google.com)

https://books.google.com/books?hl=en&lr=&id=4VUPyp1XEikC&oi=fnd&pg=PA1&dq=how+do+you+make+a+torsion+box&ots=-wvUjANmEp&sig=6qEa4haARHTrz-Q-2rUYiB79MHo - Highly integrated inner structure of a torsion box of an aircraft lifting surface (FJH Ruiz, FJC DOMINGUEZ – US Patent 9,701,393, 2017 – Google Patents)

https://patents.google.com/patent/US9701393B2/en