There are a number of skills students need as they begin working in a wood shop: Squaring a board, cutting material to spec and using the various machines. In this activity, I re-use 2x4's from last year's construction class to teach the above skills while each student makes a couple Giant 'Jenga' Blocks.
The students in this group are anywhere from grades 9-12 and vary from zero experience working in a wood shop to taking the class a second time for fun. Even the students who have taken a woods class in the past enjoyed making the blocks as it gave them an opportunity to refresh their memories regarding the various machines.
While students could certainly meet our learning objectives cutting any piece of wood to a specific size, using the dimensions of a Block Game gave them a reason to be exact in their measurements and had the added benefit of allowing them to play the Block Game when they were finished.
2x4's - approximately 16 inches per student
Cross Cut Saw
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Step 1: Step 1: Prepare a Board
Since we are re-using boards from another class, I did learn the hard way to check for nail pieces in the boards. Run a nail detector over the used 2x4's to ensure there aren't any nail stubs left over. I still need to have my Jointer blades sharpened from hitting a nail stub.
Once the boards are clear, I demonstrated how to use a miter saw and each student cut a 16" piece of board from a longer section of 2x4.
Step 2: Step 2: Joint a Side
Next, each student ran their board through the Jointer to flatten out an edge. Again, this is the first time many of the students had ever used a Jointer and I demonstrated how to safely use the equipment and then each student Jointed their board.
As we worked through the jointer, we also took time to talk about the grain of the wood. The jointer tends to chew up the wood a little if you work against the grain. This gave us a real reason to analyze the grain of the wood and look for ways to determine the direction of the grain.
Step 3: Step 3: Planer
Giant Jenga has dimensions of 1 3/8 x 2 3/8 x 7 1/8. To get our 2x4's to 1 3/8, I again demonstrated a new machine, the planer. Students took their 2x4's (typically 1 1/2 inch tall) down to 1 3/8 by taking 1/16 off of the top and bottom.
This step was actually a little more challenging for students. While the planer is a fairly simple and safe machine to use, students struggle a little with the math and fractions. Planers are set to a finished height. Since students needed to take a little off of the top and the bottom, they had to set the planer to take off 1/16" on each pass. But, the planer is set for final height. The first pass needed to be 1 7/16" and the second pass to 1 3/8".
This is another area in which the grain of the wood is important. The planer is another machine which has been known to chew up the material if you feed it through against the grain.
Step 4: Step 4: Table Saw
A 2x4 is generally 3 1/2 inches wide. To get this to spec, we needed to cut the 2x4 to a width of 2 3/8. For this, I demonstrated and the students used the table saw.
As we set up the table saw, we took the time to talk about the height of the blade and how in future projects, we might purposefully set the blade lower than the height of the stock in order to cut a rabbet. We also discussed how the fence is set up to take the kerf into account and that it is safe to set the fence at the final width specification.
Step 5: Step 6: Cross Cut Saw
I'm fortunate enough to have 2 table saws in my shop so I leave one set up with a sled to cross cut. Here I spent some more time on vocabulary, discussing the issue of kerf, where the blade itself chews up some of the wood. I instructed students to mark their boards at 7 1/8 inch but then again at 14 3/8 inch to accommodate the 1/8" loss to the blade.
As with the previous steps, I demonstrated how to use the equipment and each student cut their own board. Students had a little difficulty aligning their measurements with the blade. We took time to discuss with which side of the blade our mark should align why a cross cut saw is a better option for these cuts than a miter saw.
Step 6: Step 6: Sanding and Staining
At this point, students had 2 pieces. Students were instructed how to use orbital sanders, the disk sander and how to block sheets of sand paper to smooth out their pieces.
Once their blocks were smooth, students were able to finish their pieces with various stains. I explained that it was better to practice staining on something simple, like these blocks, than on a finished piece of furniture.
A couple of students stained and then realized that they hadn't sanded their piece sufficiently. I had them re-sand and they ultimately liked the distressed look of their block and decided not to re-stain their work.
Step 7: Step 7: Assessing Their Work
Our district uses standards based grading. This project used two of our standards: 1) meeting industry standards and 2) creating useful products.
For the first standard, I assessed the students work by measuring their final product. The carpenter's union allows for a tolerance of +/- 1/32". I started with students at a 4 (our equivalent of an A) and docked them a .5 for each 1/16" they were off in any dimension.
For the second standard, I assessed the overall finish of the product. Here I was looking for mill marks and burring as well as even staining. Again, I started at a 4 and docked them for the various imperfections in their finished product. That said, we were re-using 2x4's from a construction class. The boards had nail holes and hammer imprints in the wood. The imperfections that needed to be addressed were those from the work they did. Both the jointer and the planer tend to chew up the wood if you work against the grain. I expected students to sand these out.
Step 8: Step 8: Takeaways
At this point students were ready to play.
Overall the project went really well. Students had a reason to square a board and cut a block to specific dimensions. When playing, it was obvious to students that some blocks made the game less enjoyable due to their being out of spec and it allowed me to reiterate the importance of accuracy in our measurements and cuts.
Surprisingly, a number of students wanted to keep their block. I thought that between the three sections of students that I would have enough blocks for two sets of games. However, I have just over enough 'in spec' blocks to play one game. Since this is a semester class, we will do this again next semester and pass along first semester's blocks to the elementary school across the street.
Timing wise, the entire project took 8 class periods. Since students used each machine one at a time, under my supervision, it took some time to finish each step along the way. However, each student was also expected to take and pass a safety test on each piece of equipment. While waiting their turn for the next step, they worked on their safety test.
I definitely plan to continue to use this project as an introduction to woodworking and the equipment in the shop. We have a recurring supply of used 2x4's from our construction class that would otherwise go to waste. This project re-purposes those 2x4's while also teaching students a number of pre-requisite skills. Definitely a win-win.
Looking ahead to the future, we are hoping to get a laser engraver as well as some wood burners. Customizing their blocks would give students an opportunity to show some creativity as well as a chance to practice using two additional pieces of equipment.
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