Raw Materials Used:

• 9 x 14.5” 1×4 lumber
• 6 x 12” long pieces of 1×4 lumber
• 3 x 10″ long pieces of 1×4 lumber
• 4 x 10-11” long pieces of 2×2 lumber 
• 1” long wood screws

Equipment Used:

• Corner clamp
• Table clamps
• Drill
• ⅛” drill bit
• Philips head driver
• 60, 120, 220, and 320 grit sandpaper
• Orbital sander
• White wash wood stain
• Table router, 1/2″ router bit

Assembly Procedure (Total ~10 Hours):

First, we used a corner clamp, screws, and drill to assemble a 12” by 16” rectangular frame using 4 pieces of 1×4 lumber. We repeated this step 3 times to obtain three 12” x 16” rectangular frames.

Next, we used an orbital hand sander and 60 grit, 120 grit, 220 grit, and 320 grit sandpaper to sand the wood, so it was smooth and comfortable to work with.

We then used the table router with a ½” bit to remove the edges of the wood.

We took one of the frames and attached 3 pieces of 14.5” 1×4 lumber to create the bottom of the crate. Then, we took one of the frames and attached one 10” 1×4 piece of lumber to one end to create the middle frame. We then took the remaining frame and attached two 10” 1×4 pieces of lumber on either end to create the top frame of the crate..

For structural support, we took the two 10-11” long pieces of 2×2 lumber, and vertically attached them to the top right and bottom right corners of the frame. Then, we took the other two 10-11” long pieces of 2×2 lumber, and vertically attached each 6” to the left from the two previously attached 2×2 corner pieces. These four 2×2 pieces provide support for the rectangular frames in the overall crate structure.

We attached the middle rectangular frame to the 4 vertical support pieces. There is a gap between the bottom and middle frames, so use extra pieces of 1×4 lumber as spacers to support the structure during assembly. The vertical supports attached to the middle of the bottom frame should be attached to the empty end of the middle frame, and the vertical supports on the corner of the bottom frame should be attached to the end of the middle frame containing the extra piece of wood.

We attached the top rectangular frame to the 4 vertical support pieces. There is a gap between the top and middle frames, so use extra pieces of 1×4 lumber as spacers to support the structure during assembly. The vertical supports should be attached at the middle of the top frame.

Lastly, we used the whitewash stain to apply 3-5 coats of stain to the crate. We applied the staining techniques as described in the instructions on the product, wiping each coat off after 3-5 minutes and allowing the crate to dry.

Challenges

• Structural stability: Since our overall crate structure does not resemble a rectangular prism, we were concerned about the structural stability of the crate. The middle and top frames were originally reversed, but this resulted in the uneven weight of the top frame to cause slight imbalance to the crate. As a result, we decided to switch the middle and top frames to the current design.
• Uneven stain coatings: There were difficulties in the staining process, due to the fact that some pieces of wood. Stain would also build up and get caught in corners. We addressed this by using 60-grit sandpaper to lightly remove the sediment clumps on the final product.

 

Cost Analysis

 

Cost Type	Cost	Price	Source	Quantity	Total
Materials	9 x 14.5” long pieces of 1×4 lumber	$3.62 /8ft or $0.4525/ft	Lowe’s	10.875 ft	$4.92
	9 x 12” long pieces of 1×4 lumber	$3.62 /8ft or $0.4525/ft	Lowe’s	9 ft	$4.08
	4 x 10-11” long pieces of 2×2 lumber	$3.25/8ft or $0.41/ft	Lowe’s	3.6 ft	$1.50
	1 in Wood screws	$5.98/50 units or $0.12/unit	Lowe’s	52 units	$6.24
	Sanding disc pads	$7.98/kit	Amazon.com	3	$7.98
Labor	Prototyping Engineers (You!) X2	$26/hr	Sarah/Gloria	24h x2	$1,200
Overhead	Facility Cost (Machine Time)	0$/hr for students enrolled in course	OEDK	24h	$0
Labor Design	Engineering and Development	$25/hr	Sarah/Gloria	1hr	$25
	Iterations	$25/hr	Sarah/Gloria	2hr	$50
Overhead Misc.	Waste and Scrap – cleaning cost	$8/hr	Sarah/Gloria	20 min	$2.67

Thus, the total estimated cost is $1,302.39.

 

Conclusion:

Overall, we are really grateful for the woodwork skills we were able to learn and apply throughout the crate-building process, as well as the valuable troubleshooting and teamwork skills. The unique structure of the crate design allows for more visibility of and convenient access to stored materials.