Connecting Stays and Rear Dropouts

I thought I would comment on the solution I used for the rear dropouts and where they connect to the chain stays and seat stays.

Images of these are on a previous post called The Process which you can find below.

Basically, on a bamboo frame connecting the chain stays and seat stays can seem challenging at first. If you use an aluminum dropout designed for bamboo frames then bending the tabs is quite simple and easy, however, if you have traditional dropouts made of steel like the ones here then the angle of the tabs and the angle of the stays will not meet.

In order to adjust for these incompatible angles I devised a technique where I use hardwood plugs and remove enough material at the approximate angle so once they are resting on the steel tabs of the dropouts they are pointing in about the correct direction for the stay to meet it.

The plug is a simple dowel which has been cut with the appropriate angle for the dropout tab but it is also drilled out with small shallow holes for increasing interlocking between the epoxy, the wood and the steel. In this example I used an oak dowel.

PC-7 epoxy has no problem adhering to steel or aluminum unlike some other brands.

The bamboo stays are then cut which means I remove one half of the tube at the end so the hardwood plug can fit snugly and fill the void left after cutting the tube.

Typically, when I build a bamboo frame I use enough PC-7 epoxy so a strong mechanical bond is created as opposed to just tacking the frame together. I also use gussets made of basswood which provide additional strength and stiffness. These gussets work as supportive triangles inside the main triangle body etc.

The gussets made of basswood are actually fun to do because they are sculptural and even though the finished product is not revealed I do still like carving them.

The Process link


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