"To Help Other People at All Times..." - a Symbolic Bridge for the BSA

I've been a member of the Boy Scouts of America from the young age of 6 and am now within arm's reach of Eagle Scout at 17. It's been a wild journey with its ups and downs, its successes and shortcomings, and all of the effects of them making me a stronger person. Some Scouts aren't as fortunate as myself, and have local units struggling with member counts, fundraising, and community engagement. Often times people will look down on these situations and say to themselves "I'm glad that isn't me" and move on. Being a rising senior at the Concord Regional Technical Center (CRTC) in Concord, NH I've learned what an important role overlooked problems play in our society, and how the solutions can be right under our noses. Over the course of this Instructable, I plan to show how something as common and seemingly insignificant as a wooden bridge can have drastic impacts on these communities and the people within them.

Supplies

While constructing a symbolic bridge such as this one, it is critical to take the ideals and values of the community it will serve into account. The Scouts value youth involvement and leadership very strongly, so my bridge design will feature materials that Scouts can safely work with themselves such as wood and plastics, or perhaps the occasional metal bracket where moving parts may be.

With regards to digital materials, I am using a wide range of software and hardware to make this project possible. I am writing this Instructable on an older MacBook Pro, which I also use to remotely control my desktop computer when I happen to be away from home. On this desktop computer I am running Computer-Aided Design or CAD software provided through my student license with the CRTC. These include Autodesk Inventor Professional 2024 and - time permitting - Autodesk Maya 2024 for realistic rendering. For a project of this type, the free plan on Fusion 360 may be easily accessible to more people, however I personally prefer the clean interface and intuitive controls that Inventor has to offer.

And above all else as was stated above, knowledge and understanding of the BSA Troop/Pack's needs, wants, and goals is the most useful material you can have. Don't be afraid to ask questions, make mistakes, and have your mind changed. If there's one thing I've learned from Scouting, it would be just that.

UPDATE: Due to time constraints, I will be unable to render the bridge in Autodesk Maya prior to publishing this article, however I will work diligently to upload an image as an edit as soon as possible.

Step 1: What Is a "Bridging Ceremony?"

In the Scouting program, there are many different ranks or "levels" through which a member progresses. Some of these are determined by age, and many others are determined by skill level or abilities. The transition from a Cub Scout pack to a Scouts BSA troop is determined by age rather than by demonstrated knowledge. There is often a "bridging ceremony" that symbolizes this transition from a younger Scout to an older one who can be a mentor to others in his or her community. In this ceremony, a Cub Scout walks across a small bridge with values and ideals important to Scouting inscribed on it, and has become a member of the older-Scout troop once reaching the other side. The bridge should be elevated if possible to symbolize how the youth will rise above their challenges and struggles to do great things in the world. The bridge should be made out of simple materials such as 2x4 lumber and plastics to demonstrate that complex and costly solutions to problems are not always better than simple and realistic solutions. And lastly - but still important nonetheless - the bridge should be fitting as recognition for a Scout who is moving from childhood into greater maturity through their accomplishments in the program. If all of these things are taken into account, the youth should have the best experience possible with learning opportunities for knowledge that so many of us take for granted.

Step 2: Brainstorming

Brainstorming has many different layers or stages, each of which gets gradually more specific than the one before it. In this case, the first stage of brainstorming is already complete: to have a bridging ceremony a bridge is needed. In the next layer we can focus on a bit more detail. We can ask ourselves if a true bridge is needed or if there could be a simpler and less expensive solution. Traditionally a wooden bridge is used, even if it consists merely of a wooden pallet with handles. Some troops are moving to using pathways laid out indoors using objects such as rolled-up sleeping bags and water bottles as sides, and a tarp as a base to emphasize the number of outdoor activities they participate in. For timeliness’ sake I will cover the design process for a simple wooden bridge as that would appeal to the largest audience and be reusable - one year after another. This leads us into the next question: what will our specific design look and feel like and what are some pros and cons of each design? There are countless answers to this challenging question, some of them being safer, more elegant, simpler, or less expensive than others.

Step 3: Research

In order to get a stream of ideas flowing, it can be helpful to observe what others have done in the same field and on the same topic before fully committing to one design. This is true in most any industry or career, and can bring challenges and roadblocks to light before you run into them yourself.

While engineering can be a difficult and occasionally discouraging process, it is one where a "canned" solution to a problem or one that comes generically prepackaged isn't usually a good idea because of the specifics of each person or group's needs and wants. I have looked at dozens of different bridges on the internet, only to find 3 with aspects or components that appeal to me and what my troop would look for in a bridge. Due to licensing restrictions I can not attach them to this Instructable, however, your use case will be so wildly different from mine that I would encourage you to find some images that you like and that you feel represent your community rather than using the "generic" options I found.

Step 4: Digital Prototyping - Modeling 1

Having reached this stage of research, I feel comfortable with the idea of starting an improvised first prototype. One of the many wonderful things about modern CAD technologies is that it often works out to be more cost-effective to "noodle around" digitally than to do so physically if the design ends up being non-functional. We'll begin by opening Autodesk Inventor and making 2×4 boards in a number of sizes. These will be the primary materials used when building the bridge. The lengths I modeled are standard lengths one could find at a local Lowe's or Home Depot type of store. This is a very simple design to make, so while it is not a wonderful demonstration of Inventor's powerful capabilities, it does keep in line with the Scouts' importance on being thrifty - both in time and in cost. Depending on the specific software and version you may be using, your interface may look different, however the general steps and processes I will describe should be applicable to a wide range of software. I will include .stl files for components whenever possible so that you can follow along and experiment at home!

Models made: 2×4 lumber - 2', 3', 4', 6', 8' lengths

Step 5: Digital Prototyping - Assembly 1

I proceeded to model a 2"×6"×60" board, and I began an assembly in Inventor. I placed 2 of these 2×6 boards next to each other, but didn't stress over the exact placement. These will function as support runners to go under the bridge for elevation. I added a 36" 2×4 to the assembly, and used constraints to align it with the ends of the 2×6 boards and create the exact placement. When it came time to add the second board to the bridge, I realized that making equal spacing in between boards could prove to be difficult using basic tools I know how to use. To solve this I modeled a 1" wide board to be used as a temporary shim for spacing. The gaps between each board will be exactly 1 inch upon deleting the spacers. I repeated the process until there were 12 boards on the bridge base, then deleted the shims.

Step 6: Digital Prototyping - Modeling 2

The design has come to a fork in the road. We need to decide if the bridge should be one solid piece for structural soundness, or if the sides should be detachable for ease of transport. The base of the bridge was designed with fitting in a sedan in mind, so I will keep the portability factor and construct mounts for removable sides. If you would like a more permanent design though, you can skip using brackets in favor of attaching the railings directly to the base.

I'll start side-mount.ipt and make a 2D sketch of what I'd like the bracket to look like. It should have two "wings" with holes for screws or bolts, as well as a "U" shaped section to slide a 2"×2" board in vertically. For tolerances on my sketch, I added 0.2" to the interior size of the mount. This way if a board expands or a 3D-print is slightly off, it can still be comfortably used. Once I made a rough outline or top view of the side mounts, I used the fillet tool to round corners and prevent cuts or injuries. After the fillet-ing, I took a screenshot with dimensions as pictured above.

I then extruded the sketch 2" to produce what can be seen in the second image above. I started a 2D sketch with one of the wings as the sketch face, and used the circle tool to produce an outline of where the mounting hole will be. This works out to be a 1/4" circle centered on the wing. We can extrude the circle in reverse to clear that area out, which results in a mounting hole for a bolt or screw (see the last image of this step for an image). Repeat the process on the other side or "wing" and the bracket is complete!

Step 7: Digital Prototyping - Modeling 3

Very similarly to Step 4 (Modeling 1), this step will be making more virtual boards of wood, with the following step being assembly of the various parts. As I discussed many of the important points to keep in mind in Step 4, I will just provide a list of boards modeled and their .stl files here to avoid being overly repetitive.

The boards just constructed measure:

2"×2"×36"

1"×6"×60"

2"×2"×60"

Step 8: Digital Prototyping - Final Assembly

The modeling of parts is now complete, and we have one last assembly to construct. We'll begin by importing bridge_base.iam as the first component of our assembly so we can mount other parts to it. Next, we can mount our hardware to the side 2"×6" boards. As stated above, these are not strictly necessary for the operation of the bridge, but make it easier to transport. The mounts can be spaced however looks best to you, which in my case was staggered unevenly to give a homemade feel to the bridge. Constrain the hardware to the side boards in multiple places so that movement of other parts doesn't impact its placement. We'll import the 2"×2" boards next, and constrain the outside of the boards to the inside of the mounting hardware. While gravity will be the only thing holding the 2×2's in place in the real world, we should hold them still in our assembly so we can work on them more easily. Finally, attach 1"×6"×60" boards of lumber to the upright 2×2 posts to make a nice handle for Scouts to hold on to. With all of that completed, you can add finishing touches, decorate and paint the bridge, sign your name on the blueprints, and celebrate a job well done!

Step 9: Reflections and Conclusion

During this project I continually thought about what I would say to my current-self's accomplishments back in 2017 when I bridged from Cub Scouts into then-Boy Scouts (since rebranded to Scouts BSA). I can't help but think how ridiculous I would have thought the idea of building a bridge was and how monstrous and unaccomplishable it would have seemed. But, through the friends, supports, teachers, and even random people I've met and gotten to know, I've become a stronger person each day, and done what was believed to be impossible. Not only will this bridge have positive consequences on the Scouts who use it for decades to come, but it has already shown me that - just as people in society - there are tremendous opportunities for growth in our everyday lives, whether we immediately recognize it or not. I feel content with the difference I've made in the world today, and especially about what this bridge will do for other people over many days to come.