Make a Cardboard Caliper

A Caliper can be used to measure the dimensions of objects. It can even allow you to measure the diameter of an object, sometimes both outer and inner. There are many different styles of calipers. In example, there are digital calipers that allow you to read measurements on a small screen to a certain precision. Others might not be digital but instead allow for measuring with marks on the shaft of the caliper. The material of these tools includes wood, plastic, or some type of steel.

This tool is used in a variety of disciplines, but most college students who enter a Technology and Design Engineering Education or related program will have to work with these. Sometimes students will be provided with them in a lab/classroom. Often, though, students will be required to purchase their own caliper. In my experience, and I know with many others, the caliper you end up purchasing may not work as well as you had hoped. This leaves you with a waste of money that most college students could have used in better ways.

This instructable is aimed at teaching college students, either in a classroom or at home environment, how to make their own Caliper cheaply. Additionally, this will help students to become more aware of technological literacy and important concepts related to this.

Objectives:

• Understand how STEL Standards, practices, and contexts can be applied to creating a Caliper.
• Understand why STEL literacy is important
• Understand more about what STEL is
• Understand how a Caliper works
• Follow a set of instructions to fabricate your own Caliper

STEL stands for: Standards for Technological and Engineering Literacy. According to the authors of, "Standards for Technological and Engineering Literacy: The Role of Technology and Engineering in STEM Education", it is imperative that everyone understands "technology's impacts on their lives, society, and the environment, as as how to use and develop technological products, systems, and processes to extend human capabilities" (Barbato, Hoepfl, Loveland et. al, 2020). While we will not be able to cover all of that in this instructable, we will hope to focus on some of these aspects to make you more familiar.

Within STEL, there are three key levels: Core Disciplinary Standards, Practices, and Contexts. Each of these levels feature important concepts in respect to their area. We will cover some of these concepts in each level as they relate to this project.

STANDARDS

Standard 2: Core Concepts of Technology and Engineering

This standard states that each part of a cohesive product will relate to each other. In the caliper we will make, this can easily be seen. We have six parts that cooperate together to create a functional tool that can measure objects. The first part is the main shaft that features units of measurement (in our case inches) and a top bar that serves as the upper bound for the measurements. The second and third parts (the sliders) serve as a lower bound for the measurement that will slide up and down according to the desired size. The front slider will feature a small extracted square that helps to add ergonomics to sliding the part up and down. Finally, the two connectors allow the sliders to come together and allow for them to slide as a whole.

Standard 2 also states that there are resources required to build a product. This is exactly what we will see as we move through this activity. The resources go beyond just the parts themselves, but others needed to manufacture this product. You will need glue to connect the parts together, a pencil to outline the products on cardboard, and a marker to bold the marks on the shaft. Of course, this also couldn't be made without having cardboard as a resource in the first place.

Standard 7: Design in Technology and Engineering Education

One concept discussed in this standard is that new designs can build off of other prior designs. This activity creates a product that we know already exists. The design is based of said product. This differs on prior designs in that it is much cheaper and made of different materials. This is an improvement to existing designs for those in the target audience: college students on a budget.

This is also an example of an iterative product, because it is a new iteration of existing designs. This is another important aspect of this standard. Design is an iterative process that can circle back to a prior design when improvements are needed.

Another key aspect is that there are no correct solutions for problems that the likes of this activity aims to solve. This solution doesn't satisfy every situation, but it isn't incorrect. It works for the target audience.

PRACTICES
Practice 2: Creativity

An important concept in the practice of STEL is creativity. This allows us to solve complex or old problems in new ways. This activity exemplifies this by taking a preexisting solution and figuring out a way to make it more affordable (and produce-able by anyone).

This standard states that brainstorming is important for creativity when addressing a problem. During the process of creating an idea for this project, I had to examine prior designs (including ideas that were addressing the same type of problem I am). Then I had to generate new ideas for how I could create a different design that was effective in accomplishing the desired goal. It is important to think outside the box when doing this.

Practice 3: Making and Doing

This standard defines making and doing in addition to declaring how they are different. Making requires us to create something, in this case a caliper. Doing is when we put together this product through hands-on activities. When we are in the process of cutting out the cardboard and gluing together pieces, that is an example of doing.

CONTEXTS

Context 2: Material and Conversion Processing

This standard discusses the different aspects of material and conversion processing when it comes to the production of products. One aspect of this is how a product can be classified: durable or non-durable. The industry grade calipers made of materials like stainless steel would qualify as durable. The cheap cardboard caliper we are making would be classified as non-durable.

Another focus of this context is on how an individually produced product could be converted into one that is mass produced. This is already being done with the industry grade caliper. As you go through this activity, I encourage you to think about how you could convert this product into one that could be mass produced.

Now we will get to building the caliper! I will provide a material list and cost estimation. If there is a range starting with $0, this implies that it is a resources you likely have lying around the house or classroom.

Material List:

1. Ruler: $0-$1 (from the dollar store)
2. Cardboard: $0-$0.87 (grainger.com)
3. Exacto Knife: $2 (from Staples)
4. Pencil: $0-$1 (from the dollar store)
5. Black Marker: $0-$1 (from the dollar store)
6. Glue: $0-$1 (from the dollar store) [Note that I used super glue]

Note that any type of glue should work fine. Optionally, you may wish you paint your caliper. You can find cheap paint and brushes for no more than $3 from a dollar store. Total cost: Between $4-$7.

• You will want to use your ruler and pencil to measure and outline the dimensions of your caliper. I will include the technical sketches with the dimensions (in inches) for reference.
• The main shaft should be 1 inch wide, and 8 inches tall. The top edge is 0.75 inches tall. It extends from the shaft 1 inch on the left side and 1.5 inches on the right. Both ends of the top edge should be cut at a 45 degree angle, in the same direction (from top left to bottom right).
• The front and back of the slider are 1.2 inches wide and 1.5 inches tall. The top edge is 0.75 inches tall. The left side of the top edge should extend 0.9 inches from the base and 1.4 inches on the right.
• The connector pieces should be 0.45 inches wide and 1.5 inches tall.
• The button should be 0.5 inches wide and 0.65 inches tall.

• In this step you will cut out the outlines you made on the cardboard.
• Make sure to put some extra cardboard underneath the subjects you cut out. This will keep you from cutting into your table.

• In this step, you will take your ruler and measure the marks you need on the main shaft.
• Use a pencil on the first go around.
• The nice part of this step is you can decide your own level of precision for your markings.

• In this step you will take your black marker and carefully fill in the outlined markings from the last step.

• Gather your connector pieces and slider pieces.
• Glue the edges of the connector pieces with each end of the sliders. Make sure to preserve the gap they will need to slide over the main shaft.
• Do this for both sides.

• In this step you will glue the small grove onto the front slider piece to help it function more ergonomically.

• I was working with super glue to put my slider together. This left undesirable residue on the surface. You can paint over your slider like I did if you want.

• The product is now finished! You can now start using your caliper to measure objects!
• The left pointed ends can be used to measure the inner diameter of a circle.
• The right ends can be used to measure outer diameter of a circle.
• The right ends can be used to measure the size of any polygon.

Reference:

Loveland, T., Hoepfl, M., Barbato, S., & Reed, P. (2020). Standards for Technological and Engineering Literacy: The Role of Technology and Engineering in STEM Education. International Technology and Engineering Education Association.