Folding Chair for Hand Tools or CNC Router

This folding chair was designed with the intention of laying it completely flat for storage (based on a Youtube video by "Mr. NK," which you can access at https://www.youtube.com/watch?v=yyEmcc5JLaY). We modified the video's design so that it has a higher seat, which is better for accessibility and comfort. It requires a roughly flat surface, so it can be used outside on even-surfaced lawns, in parking lots, or indoors. We made multiple prototypes of the chair before finalizing the design. At first, we used hand tools, which was effective, but not as clean as when we used a CNC router with a 1/4 inch bit. Either works well, but the attached drawings' dimensions in these instructions were made specifically for hand tools.

Supplies

a handsaw or CNC router

3/4 inch exterior grade plywood

sandpaper

3 inch door hinges

oil-based wood stain (the blue stain we used is from Amazon: https://www.amazon.com/gp/product/B0776ZTGT2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1)

polyurethane finish/sealant

wide brush

Step 1: Dimension Drawings

a. If using the CNC router, either download the CAD file below, or draw your own with desired dimensions.

b. If using a jigsaw, make your own drawing of the chair, using the pdf. attached below.

Step 2: Cut Out the Chair

a. Cut out the chair using the CNC router, using a 1/4 inch bit.

b. Cut out the chair using the jigsaw. Try to get as close to 1/4 inch margins as possible. It helps to trace an outline of the chair on the plywood first, using the drawing's dimensions above.

Step 3: Sand the Curve at the Top of the Chair

3. Use a belt sander to trim down the back of the chair, so that the piece of wood is slightly curved. This makes it a more supportive and comfortable back-rest.

Step 4: Use a Wood Router

4. Use a wood router to smooth out the sides. Use sandpaper to smooth out the sides, if desired/necessary. Then, use an orbit sander to smooth the surface of the entire chair.

Step 5: Sand the Chair

Use sandpaper to smooth out the sides, if desired/necessary. Then, use an orbit sander to smooth the surface of the entire chair.

Step 6: Make the Hinge Holes

Use a drill press to create holes for the hinges.

Step 7: Screw on the Hinges

Using a drill, screw on the hinges. We used an internal hinge method for the upper legs of the chair at first, but the plywood actually broke due to its lack of thickness. We recommend using three hinges in total: one for the seat as shown above, and two for the chair legs.

Step 8: Stain the Chair

Stain/finish the wood. Make sure to do this carefully to avoid drips.We used a blue and medium colored stain for our chairs, then coated them in a polyurethane sealant.

Step 9: Optional: Attach Locking Mechanism

Attach some sort of locking mechanism to keep the chair from unfolding during transport. This is not completely necessary if the chairs are made for the same location and don't require frequent movement.