Lesson: Basics of Nonvisual Wood Working

Authors: David Nietfeld, Wade Goodridge, Peter Anderson, Sarah Lopez, Natalie Shaheen 

Class Size 

• Originally taught to groups of 15 students with multiple teaching assistants. An instructor to student ratio of at least 1:5 is recommended. 

Lesson Structure 

90 minutes 

• Intro/explanation: 20 minutes 
• Individual practice: 70 minutes 

Objectives 

Students will be able to: 

• Accurately measure and cut balsa wood either straight or at a desired angle, using a variety of tools. 
• Assemble pieces of balsa wood using glue dots and hot glue. 

Prerequisite Knowledge 

• None 

Accessibility 

• Jigs with tactile markings are used to support accurate nonvisual cutting. 
• Hand-under-hand is used to demonstrate tool use.  

Materials 

For each tool, aim to have 1 for every 3-4 students. 

• Balsa wood rods (½” x ½” is given as an example, but other sizes may be used) 
• ~4 feet per student
• Angle/Length cutting jig 
• Clamps (various sizes) 
• Crosscut saw 
• Miter box 
• Angle cutting shears 
• Hot glue guns 
• Hot glue sticks 
• Small cups of water (for use with hot glue) 
• Empty coffee cans (to hold hot glue guns)  
• Glue dots – 10+ per student 

Note: Refer to Accessible Lab Equipment & Instructional Materials for additional information regarding specialized tools/materials. 

Preparation 

1. Determine a procedure for all students to practice with each tool with relatively close supervision. Depending on your class size, this may mean creating stations for each type of tool and having students rotate; it may mean working with one tool at a time; it may mean small groups work through this lesson while other students are doing something else. Note that this lesson requires a higher level of one-on-one instruction and supervision than most lessons.  

Procedure 

1. Introduction.  
   • Tell. “In order to build your model for the Place of My Own project, or to build things for other projects you may wish to do in the future, you will need to be able to cut the pieces you need, and assemble them securely. This lesson will introduce you to several basic tools and techniques to cut and assemble balsa wood to make various structures.” 
2. Safety.  
   • Tell. “All of the tools discussed can be safely used nonvisually, once you are familiar with how they work. With each new tool you are introduced to, take some time to feel all parts of it and orient yourself to the blade, handle, etc. For cutting tools, you can carefully touch the sharp parts while the tool is still (or off) so that you know where they are and what they are like. Touching the sharp parts during exploration is a critical piece of understanding how to safely use the tool.”  
   • Note: Hesitant students will benefit from a demonstration of what touching the sharp parts carefully means. 
3. Balsa wood.  
   • Do. Pass out one 4’ piece of pre-cut balsa wood to each student (or two pieces if less than 4’ is provided).  
   • Tell. “Balsa wood is light, doesn’t crush easily, cuts without leaving many splinters, and works with most adhesives. We’ll be using it a lot for our models, so we’ll teach you how to use it now. You will need to cut this into pieces for each part of your model.” 
4. Introduce the tools available. 
   • Teach. Introduce miter box, crosscut saw, angle/length cutting jig, angle cutting shears, glue dots, glue gun.  
   • Tell. “We’ll be using these tools throughout the project so if your skill doesn’t come immediately, there will be plenty of chances.” 
     • Angle/length cutting jig (use it with crosscut saw). Teach. The jig lets anyone make a straight or angled cut. To work well it is recommended that the jig itself needs to be clamped down to the side of the table. It is most effective when the balsa wood is held down as well by pinching it into the adjustable fence. Have students place their board against the fence after adjusting the fence to the desired angle and tightening the wing nut to hold it. Students cut by holding the saw along the edge of the jig and moving the saw parallel to the edge. Allow students to explore the jig and try the techniques. 
       • 
     • Miter box (use with crosscut saw). Teach. The miter box should be clamped to a table so excess materials from the cut will fall to the floor. The balsa wood is loaded into the jig so it aligns to one fence or the other. The cut is made by slowly reciprocating the saw back and forth in the provided slots of the jig. You have slots to cut at 90 degrees to the axis of the board or at 45 degrees. Show students a hand-under-hand technique to show how to crimp it to the edge with your fingers while pushing down with your thumb. Allow students to explore the jig. 
       • 
     • Angle cutting shears. Teach. The shears are held in a hand like a set of pliers. The balsa board is held on the larger flat section of the shear blades and when the student squeezes the shear handles, keeping fingers clear of the jaws, the top jaw is brought down and slices through the balsa board. You may hold the balsa in the shears at any desired angle for the cut.  
       • 
       • Note: This technique does not produce as clean of a cut as the miter box or angle/length jig
     • Crosscut saw (use with miter box, angle/length cutting jig, or on its own). Teach. The razor saw has many small teeth that are sharp. This means that when sawing almost no downward force is required. Just move it back and forth until you hear or feel the extra piece drop off or feel the saw start to cut into the jig. Allow students to explore the saw. If students are nervous about getting cut, the teacher can place the blade of the saw in their palm and gently grasp the saw by the blade so that students can begin exploring the saw without worrying about cutting themselves. It is also helpful to explain to students that in order to cut themselves with this saw they would need to rub their fingers back and forth over the blade. Once they have general familiarity the students should explore the saw without the teacher’s hand on the saw. 
       • 
         
     • Glue dots. Teach. The glue dot is a temporary adhesive to hold things in place while you work on something else. They are on a roll with a plastic backing. Unroll one, tear it off, stick it to one side and then join the two sticks together. They are neat because they are repositionable. If two glue dots get stuck together, do not try to separate them, it never works. If one gets rolled onto itself, dispose of it. They are stretchy if you need to make them larger or go around a corner. 
     • Hot glue gun. Teach. A permanent adhesive to stick things together. The glue gun melts a tiny amount of a stick of material using its very hot tip, it comes out as an extremely hot liquid that hardens in 20 or 30 seconds. A trigger advances the stick. The resulting joint is strong, brittle, and can’t be repeated easily. The best way to use it is to lay down a drop or line of glue and then press the other part into it. It has a tendency to squeeze out the sides.  
       • Allow students to explore cold glue guns and locate the parts of the gun that will get hot and where the glue will come out.  
       • Tip: to help prevent burns, you can dip your finger in water before you begin to glue. If you accidentally touch the glue, this will help it not stick and burn you 
       • Tip: If you do get the hot glue on your fingers, quickly rub your fingers together. This will roll the glue up into a ball and help you get it off before it burns you. If this happens, you can also dip your finger in water, and it will quickly cool the glue before it burns.  
       • Hot glue guns that are not in someone’s hand should always be placed in an empty coffee can (or similar container) so everyone knows where they are.   
5. Construction technique - Copying.  
   • Tell. “In your design, you will often need multiple pieces with the same length or the same angle. If you need something to be the same size or angle as something else, use the first piece you measured and cut as a guide to make the second piece. Oftentimes what matters most is that pieces are the same, not their actual measured size.” 
6. Material width.  
   • Tell. “When you draw your design, you likely drew the edges of your structure as thin lines. However, when you build it in real life, the edges will be pieces of wood with significant thickness. If you do not account for this, you will end up with a structure that is bigger than your design. When you measure and cut your pieces, be sure to factor in the width of the materials in advance. For example:” 
     • “If you want to build a 13” x 10” box out of ½” balsa wood you need to cut two of the sides to be 13” and two sides to be 9” (10 - ½ -½).” 
     • “If you want to build a 10” x 10” box out of ¼” balsa wood, cut two sides to be the full 10” and two sides to be 9.5” (10-¼-¼).” 
     • “Remember the 10” x 10” x 13” constraint of the Place of My Own project applies to the EXTERIOR dimensions of the fully built structure, not the internal dimension or its individual parts.” 
7. Practice.  
   • Students do. Have students practice using these tools to make a simple construction. You could assign a practice exercise, such as “Build a 9” x 9” box”, or you could have students construct their foundation box for <MB1-Forming Foundations>. Students should experiment with at least two methods of cutting and both glue dots and hot glue. 
   • Do. As students are working, support them individually as they first use each sharp or hot tool. Once they have used it once with you, allow them to continue their work on their own. 

Standards Alignment 

• This lesson does not directly align to any NGSS or Common Core standard, however, in the context of this unit, it supports the standards taught in other lessons by providing the skills to make a hands-on model which is used to reinforce the concepts taught throughout this unit.  
• Consider checking your state’s technical education standards to see if there are other applicable standards about tool safety or operation, accurate measurement, or model construction. 

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