Hook Joint Press Fit

Ideation

When deciding on which press fit joints to design for my project, I looked through various examples with different connecting methods until I narrowed my interest to the half lap and hook joints. To help in my decision between the two, I began with creating a rough example of how I may use the half lap joints around a circular shape. Not yet convinced on this joint style, I developed a preliminary hand sketch on how I would uniquely implement a hook joint. At this point, I felt satisfied with my idea, as my goal for this project was to challenge myself with a unique joint. Therefore, I proceeded with drawing a detailed, parametrized hand sketch of the pieces on a flat plane.

Reading Reflection

Reflecting on the reading segment from Things Fall Together by Skylar Tibbits, the text had a significant influence on the way I approached control over my design process. In the reading, it is discussed how we tend to assume that we have full control over a design, especially when situated in the pre-production phase. However, this changes once the product has been fabricated as an endless variation of modifications can be applied. While lacking control over an outcome may initially be perceived as concerning, the reading highlights that unexpected results and discoveries can arise in these uncertain circumstances. Applied to our project steps, these educational and surprising moments may occur in the refining step, where physical manipulation can take place to reach one’s desired results. Considering the layers of this discussion in conjunction with one another, I was encouraged to employ a combinatory approach throughout the various stages of my design process. Finding this balance involved producing intentional and thorough designs while also surrendering control to results influenced by my materials and other external conditions such as software and machine performance.

Digital Design

Having produced a detailed hand sketch, I used rectangular shapes and lines to construct the sketch in Fusion-implementing construction lines as well as constraints like coincident and equal during the process. After this, I extruded my bodies and created separate components in order to be able to move the elements around and observe how the joints would fit in the kerfs. My final steps before exporting and laser cutting my design involved reviewing sketch accuracy and parameter details such as the width of the wood. Unfortunately, after my first round of cutting my design, the hooks turned out to be too thick to fit through the kerfs, despite attempting to calculate these details carefully. After having discussed with Makerspace staff and peers who had encountered a similar issue, I proceeded with the recommendation to multiply my width of 0.125 in. (⅛ in.), changing my kerf width dimensions to 0.25 in.

Fabrication

In addition to encountering the issue of my hook joints not fitting into the kerfs during my first round of cutting, one side of joints and kerfs appeared to have been cut off. Tracing my steps, I am led to believe that this occurred during the design resizing step in Illustrator-having missed these sides when grouping the bodies. Having concluded that I would have to re-cut my design, I made the suggested adjustments to the kerfs detailed in the previous step, in hopes of an improved outcome. As I assembled my pieces from the second round of cutting, the hooks fit through the slits with slightly more room than desired. The internal part of the hooks were also thicker than anticipated, causing the overhang to be on the shallower side.

Finishing

In an attempt to address the thick hooks, I used sandpaper to lightly file the joints down prior to assembly.

Outcome

Evaluating my press fit outcome, I am satisfied with how I was able to conceptualize an original hand sketch and produce a 3D form with close resemblance and as a working design. On the other hand, aspects I would have liked to improve are the dimensions/thickness of the hooks and kerfs as this would have made the structure sturdier and produced cleaner-looking results. Additionally, while I do not mind producing an artistic piece, it may have been interesting to consider ways my design could become functional for use.