Morning Lab February 5, 2013 8:10 – 12:00pm

I talked to Pete some about the bike support system for the pump. He told me the pump group is planning to build a pump that will convert the rotational motion of the pedals into linear motion for a piston that will pump the water. If this is the design the pump group is working with we may want to rethink our bike stand concept as the rear wheel can be removed from the bike if they are not using it to directly drive the pump. I’ll leave the sketches that Pete and I drew up and you guys can ask him to help clarify what I said.

I played around with mitering bamboo joints using the horizontal band saw and the rotary sander. The horizontal bandsaw makes very nice clean angle cuts in the bamboo rods but the rotary sander was challenging to get a tight fit that didn’t change angles or have the bamboo rods become out of plane (i.e. when you put them together they wouldn’t lie
flat on a table as they are askew)

I messed around with some more lashing techniques and attempted, without success, to make a lashing that would secure angled pieces.

I felt a little lost in lab today as I was ready to start working on the bike stand, then after talking to Pete I realized that the pump was not going to be run off the rear wheel and I wasn’t that clear on the design proposal for the pump. Maybe you guys can talk in more detail with the bike pump group so that we have a better understanding the their needs.

I’m down to meet and discuss where we are headed sometime this week outside of class.

Afternoon Lab February 5, 2013 12:10 – 3:00pm

For the afternoon lab, the team decided to collaborate with the Bicycle Water Pump Team who are interested in a bicycle stand for their bike pump. After discussing details further the team decided to continue their work on bamboo joints. The team decided to split up into two groups to construct two bamboo joints.
Group 1: Audrey and Megan – Hole-Tie Joint
Group 2: Kimber and Mariah – Plug-in Bolt Connection Joint

Group 1: Hole-Tie Joint
Audrey and Megan started their joint construction by drilling a hole into the smaller piece of bamboo using the drill press.

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Photo 2.1: Audrey and Megan drilling a hole into bamboo using the drill press.

Next they used twine to weave through the hole and around the attached bamboo. The results of this were that it wasn’t as sturdy as we would have liked it. One of the challenges was getting as much twine as possible through the hole. A method that was tried was attaching the twine to a piece of wire as seen in Photo 2.2.

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Photo 2.2: Audrey and Meghan using wire to weave the twine through the hole in the bamboo.

Photo 2.3: Audrey and Meghan’s finished product.
Photo 2.3: Audrey and Meghan’s finished product.

Photo 2.3: Audrey and Meghan’s finished product.

Group 2: Plug-in Bolt Connection Joint

Kimber and Mariah decided to expand on the Positive Fitting Connection Type B joint Ethan had worked on in lab one. To successfully create a strong joint, we used three pieces of bamboo a large, medium and small piece as seen in Photo 2.4. Each of the pieces of bamboo could fit into the other pieces. We started by drilling a large hole into the biggest piece of bamboo seen in Photo 2.5.

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Photo 2.4: The three pieces of bamboo used to create the plug-in bolt connection joint. Notice that the smaller piece fits into the medium sized piece.

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Photo 2.4: Mariah drilling a hole into the biggest piece of bamboo using the drill press.

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Photo 2.5: Kimber continued to file the hole in the bamboo more in order to effectively fit the other piece of bamboo into it.

The team then tested to see if the medium sized bamboo piece could fit into the hole the team drilled as seen in Photo 2.6.

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Photo 2.6: We successfully drilled a hole in the bigger piece of bamboo that fits the medium piece of bamboo.

Next, we drilled a smaller hole on the other side of the largest piece of bamboo in order to fit the smallest piece of bamboo through both the largest piece of bamboo and the medium piece of bamboo. (See Photo 2.7).

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Photo 2.7: We successfully connected all three pieces of bamboo together through the holes we drilled.

We then wanted to use twine to completely secure the joint together so we then drilled a small hole through the medium and small piece of bamboo to connect the two pieces. Photo 2.8 and 2.9 show the small hole that goes through both of the pieces of bamboo.

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Photo 2.8: Mariah drilling the connector hole for the twine.

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Photo 2.9: The medium and small piece of bamboo connected with the small drilled hole for the twine.

We wound the twine through the small connector hole and around the largest piece of bamboo and the joint held up really
well. As seen in Photo 2.10, the ending product was very successful and we were extremely proud of our work! external image -d528JQ90TP5WT4FOLAFsLBKO3xQmDdw2-nWCsZD0KrxySFJpLTxgJE0gQMlAoSaEJlTFC6vPpm16AdrwJDklZkIcxi85JIuRXeUMBxJ3he1ZhAYCcPbjvUE

Other General Observations:

  • The more the holes in the piece of bamboo the weaker it got.
  • Making the joints close to the notches in the bamboo creates more stability.
  • Was a very successful joint, but takes time.

I’m thinking we should consider designing a new decision matrix. We continued to work on the bike stand today, and shared more communication with the water pump group. Through this process, we are learning about the client relationship; where the water pump group is our client, asking us to produce something for them. And by expanding our circle, we have more minds to share ideas and interact with.

As far as design goes, we worked on connecting the four bamboo pieces more securely.
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