Collapsible Shelf

Created by four classmates in a manufacturing course at Piedmont Hills, the collapsible shelf is a creative take on the common shelf. It consists of two shelves that are connected to each other like Lego bricks. Our design uses the force of gravity to pull down the shelf by itself. It can also return to its neutral position by pushing the bottom up and locking it in place with knobs. The following steps are a guide to make your own; however, if you are unfamiliar with CAD, you can just use the Fusion files attached to each part.

1. Fusion 360 (or another CAD software)
2. MakerBot Print (or another slicing software)
3. 3D Printer
4. Clipper
5. Small Metal Spatula
6. Sandpaper (optional)
7. 8 Self Drilling Screws

In a CAD software of your choice, create the base drawer with the following steps:

1. Make a 24" x 12" rectangle and extrude it by 16" to make it a prism
2. Use the "Shell" function and select the designated walls to hollow out the rectangular prism, leaving a shell of 1" on each side.
3. Within the inside of the right wall, make two rectangles. The first will be 1.625" x 14" and placed within the center of the right wall, but touching the top edge of the upper wall. The second will be 5.188" x 1.625" and 0.6875" below the upper wall. The two rectangles should be perpendicular to each other.
4. On the same sketch as the rectangles, draw a circle of diameter 0.50" that is 1.5" from the top of the upper wall. Make sure that this circle is centered.
5. Cut the two rectangles into the wall by 0.5".
6. Cut the circle into the wall by 1".
7. Repeat Steps 3 and 6 on the left side, making sure that the second rectangle of both sides face the same way as this will be the entry point of the secondary drawer.

To be able to mount the shelf onto a wall, go through the following steps:

1. Select the right outside wall and start a sketch. Draw a circle of diameter 0.5" that is 2" from the top of the shelf and 1" from the side. Do this for the lower and upper end of your wall.
2. Cut the two circles into the wall by 1".
3. Repeat Steps 8-9 on the left outer wall.

In another file, create the secondary drawer with the following steps:

1. Make a 21.8" x 12" rectangle and extrude it by 15" to create another rectangular prism
2. Hollow the sides by using the "Shell" function and select the two walls opposite of each other. The walls should be 1" thick on all sides.
3. On the outer right wall, create a 1.5" x 1.5" square 0.75" away from the top edge, making sure that it is centered.
4. On the same sketch, create a circle of diameter 0.5" and place it within the center of the square
5. Extrude the square (but not the circle) outwards by 0.6".
6. Cut the circle into the wall by 1".
7. Repeat Steps 3-6 on the left side.

NOTE: You may see that our printed version has a cut rectangle (similar to the base shelf) within its inner walls. Do not worry about this as it should not be in the design.

The final step of designing the collapsible drawer is the knobs that will hold it in place so you don't need the extra space!

1. Draw a circle of diameter 1".
2. Extrude this circle by 0.50".
3. Draw another smaller circle of diameter 0.4375" on the top of the cylinder you just created. Make sure to center the smaller circle within the bigger circle!
4. Extrude the smaller circle by 2.25".
5. Repeat Steps 1-4 for the second pin!

As of right now, we essentially have a collapsible drawer which isn't a shelf. So, to make it an official collapsible shelf, we must create a way to mount it to a wall using the following steps:

1. Draw a 14" x 2" rectangle.
2. In the same sketch, draw a circle that is 1" from the top of the rectangle and make sure that it is centered!
3. Extrude the rectangle (without the circles) by 0.25".
4. Make another sketch that is perpendicular to the first rectangle.
5. Draw another rectangle that is 14" by 2". Make sure the 14" side of this rectangle is completely lined up with the 14" side of the other rectangle.
6. Repeat Steps 2-3 on this rectangle.
7. Repeat Steps 1-6 to create the other wall mount.

After designing the base drawer, secondary drawer, and two knobs, it's ready to print!

1. Download the files from your desired CAD software as STL files.
2. Upload them into your desired slicer program.
3. Depending on how big you would like your shelf to be, print the parts one by one, or scale it down and print all at once.
4. Choose "Break Away Supports" as there are pieces that will print poorly without them.
5. Export your parts from the slicer program and upload them onto your 3D printer.
6. Print!

Once the shelf has fully printed, there are only a couple more steps to follow!

1. Carefully take out each piece from the printer.
2. Peel the excess supports from each piece.
3. Use a clipper and small metal spatula to cut away the excess supports within the hollowed areas of the shelves.
4. Consider using sandpaper to smooth out the rough edges caused by cutting away the excess.

Note: Depending on if you scaled the knobs down, they may be very small, so be extra careful with its removal or else they'll break!

Finally, assemble the shelf! (Note: The wall mount is not included in the physical replica)

1. Attach the wall mount to the base shelf by aligning the 0.25" holes of both components and use two self drilling screws to keep the wall mount from falling off. Repeat this for the other side.
2. Place the base drawer and secondary shelf so that the extruded square knobs of the secondary drawer line up with the cut edge of the base shelf.
3. Slip the secondary drawer within the base shelf.
4. Use the knobs to keep the secondary shelf from extending.
5. Place on any desired wall and use the remaining four screws to attach the shelf to the wall.
6. When you want more shelf storage, take out the knobs simultaneously and let the secondary shelf slide down.
7. Enjoy your extended storage!