Bamboo Beam Bicycle is Complete

All the parts have been installed and the first Bamboo Beam Bicycle is Complete and made it's appearance at the Detroit Bike City North American bicycle show.

 I have put about 30 miles on this bike and other then the choice of seat post wont let me lower the set to the point i need to do a long ride on the frame handles great. The rear triangle is a bit to stiff as i can make the wheel skip by standing on the crank. The last bike i did that to was a Cannondale I had in 1989. and that was one stiff frame. 

Frame number 2

All parts have been bonded and assembled. I learned a lot, most important is that I really needed to keep to the mind set that I am not welding. The internship and apprenticeship I did was on steel this has aspects of steel but it is still composites. I realized this as i started frame number two. Fraim two is a bit more complex and yet simplified. I was frustrated by the somewhat inconsistent diameter of the bamboo but i still loved its strength so for frame number two i made a cored/ mandrel wound tube made working with it made a huge difference. The satays are made from split bamboo that was bonded, and then shaped again giving me uniform parts. The one inch parts can still be made from bamboo the one inch seams to be both uniform and relatively free from splitting.

 The short bamboo tube I made for what is the modified seat tube was bamboo and was made quite uniform when i sanded it with 120 grit paper on my orbital sander. When mitered it fit quite snug and i attached it with Bob Smith Industries cyanoacrylate glue. This stuff is supper strong and versatile. Back when I was working at Valio our prototype people used it make all sorts of parts for like small cams and gears and they worked as well as production molded parts

Other brands exist but after trying them all this one is the  one that does the trick, Krazy Glue brand is good in a pinch but it leaves bubbles which reduces the strength as air has no strength.  

Bonding to Aluminum

It may be necessary to attach the bamboo to Aluminum like the head tube or bottom bracket shell. As little "engineering type information" on these parts are available for working with composts as they relate bicycles the information has to be , well extrapolated. First off bonding to ferrous metal with fiberglass, carbon fiber or similar material requires that the metal surface be properly aggravated. This may entail the use of sandpaper like 60 or 80 grit emery, bead blasting and the most extreme of all knurling the metal.

However When it comes to aluminum you have the additional problem of the aluminum oxide, the protective layer that forms over all aluminum as it oxidizes. Add into the mix the little issue that aluminum has high coefficient of thermal expansion and you have a material that requires some thinking when using.

So here are the steps as they were taught to me in several classes at MSU.

Step #1 controlling or balancing thermal expansion of the aluminum  head tube, bottom bracket and dropouts outs. Materials tend to expand in the direction of greatest materiel dimension. in the case of the tubs that would be the length of the tube. Drilling the holes at evenly spaced intervals helps to balance the expansion so that the amount of movement is held to a minimum thus reducing the effect and negative effects.

Wikipedia has an excellent write up on the coefficient of thermal expansion. Most interesting is the example of rails bent due to heat. http://en.wikipedia.org/wiki/Thermal_expansion   Notice that the railes expanded in length and that is most noticeable but most inportrnt to remember is how much heeti is actuyaly requered and how long the part must be.

Step #2 aggravation of the surface with drilling and emery  to improve the ability of the Epoxy to adhere to the aluminum takes several steps to assure a reliable bond. Once the holes are drilled the surface needs to be scuffed with emery paper 40 to 60 grit. This step increases the surface area and provides a bite for the epoxy and more surface equals more hold

Step #3 Etching., aluminum oxide is the protective surface that forms on aluminum based on time and exposure to oxygen. One way to remove the aluminum oxide is 60 or 80 grit emery, however this only last about three hours so acid etching is the way i make sure i have the best bond possible. Phosphoric Acid i one but for cost and simplicity Permatex Rust Dissolver Gel a pink gel product actually has several acids int including Phosphoric and its stick nature is great. Use the product with gloves on and then rinse with water and rey just before use . 

Gig or fixture

So the next step from the design was to setup a datum and gig.
$100 of one inch extruded aluminum profile and hardware and then the hard part, centering cones. Well that was actual a deal. I found a place that sells plastic balls for fire works shells. The shell has a center hole I drilled to 1/4th inch and then I made a plywood circle base some Crazy Glue and washer and these haves make fantastic centering cones.

Chapter One The Design

Lets start with the design. Got to start some where. I have always liked the Beam  frames  of  Zipp and Soft Ride power V. when i saw this wood fixie at  http://www.fixedgeargallery.com/articles/stolpmann/

I knew the design had to be a V  so hear she is

The design was first created as a model in SolidWorks permitting me to optimize all aspect s of the design including alignment of components like wheel, rear cog and crank then go on to creation of the gig. When designing  in a 3D environment like UG, SolidWorks, Caria and similar the advantage is that you can position parts and even do a bit of FEA to see if the system will take the load ore not. It helped to start with a proven design and maybe 25 years of  engineering and working  in a bike shop that built frames from scratch in the late 80s. A education in classic Italian bicycle construction goes along way when put in the hands of an engineer.

Onward and foreword. My first job was at a small bicycle shop in Chicago called Roberts Cycles run by a Richard Bono.

I got my introduction to building bicycles early . The educations was a good one and latter it was reinforced with a long list of engineering skills as well as  welding brazing cad mill metal and composite materiel work.

But i have always like ed the hands on approach of making something with my own two hands. I was never intimidated by the mills and CNC's i worked or the welders I had to use in my R&D career but i absolutist hated that that all this equipment say for the CNC / CNC router will set you back a few bucks and takes up space like no ones  business.

So when i saw a Bamboo bike at a show  and rode one i was hooked. Considering that it can be built with come simple saws, and some rotary grinders, a gig , carbon fiber tow and epoxy and you have a bike.

Time to apply the Engineering education.

I realize that we live in an amazing free country and we have freedom to think and freedom to say what we feel. With all freedom one needs to learn restraint and before one grabs the keyboard and type up comments about a subject thy know little if nothing about.

I have read my last comet about the Renovo wood bicycle and Ken Wheeler the designer and engineer. Ken took a material and created a an amazing product. And just because you don't understand how the material can be turned into a product that dose not make it necessary to instantly croquette and make un educated comets.

Wood happens to be the original fiber compost materiel even before Fiberglass, Kevlar and Carboniferous and unlike the exotic materials listed wood is cheep and so easy to work with. No expensive tools no dangerous welding, just saws files, glue and some gigging. OK if you want to go like the Renovo exotica wood you can go to the CNC router but even that is quire cheep today about 5K.

People like Ken keeps me believing that there are still people in the world able to think outside the box.

Interesting though that the Renovo is designed to utilize nodes just like Bamboo does naturally so why not just use bamboo?

Like all materials Bamboo has its "character" that has to be overcume however  with a bit of thinking and Bamboo can be just as good if not better. Good to remember all materials need to be engineered.  As I learned vary well when I developed the Compost Skin On Frame Kayak. The prototype of which is nearing completion