aarn: regular pattern cargo rack [bicycle]
About a year and a half ago I started mulling around the idea of making a bent metal cargo rack. I toyed with the idea of cutting a coffee cup hole into the rack and a long slot for a u-lock - but ultimately I favored the simplicity of just a fancy looking rack. Originally, the thought was that the metal of the rack would come up behind the bars and clamp into an integrated rack-stem clamp thingy. Last week I realized that I have no interest in making a stem - at least not right now - and I finally came up with the missing link of how it would…link…to the bicycle.
I really wanted to style another item into in my “regular pattern” series (see aarn: regular pattern stairwell guard turned public art [arch]) and while it looked really wonky on the computer, I think that it looks pretty great on a bike. The rack geometry is custom fit around my dying daily-ride bicycle. The vertical-ish portion of the rack is parallel to my 73-degree headtube, and the struts are designed so that the surface of the rack is perfectly horizontal with two contact points built on precision shoulder screws to minimize twist and rotation around the front axle and increase the rigidity.
I cut all of the 0.125-in aluminum structural parts on the CNC router in my office and then brought them over to a friend at a machine shop who helped me make the main bends using a brake, and a hydraulic arbor press loaded with a 1-in ball bearing for the strut tabs. As is always the case on first attempts, the first time through forming the rack made for some undesirable scratches and dents trying to iron out the process - but hey, look at my bike, it’s about to fall apart. After a little polishing and filing I was able to get most of the big marks out of the finish.
A drilled and tapped shaft collar clamps the top of the rack to the quill stem. I really hate the look of racks that attach to the handlebars, so when I figured this out last Wednesday I was able to design the rack in a day. Exactly one week turnaround from design to fabrication and assembly. I had to remake the struts once because I ignored the geometry that I developed, but it was an easy fix.
I think that it turned out pretty well. Higher res photos are on my flickr. I would consider making a few more of these, but they would be really expensive and would have to be custom to fit the bike geometry - unless I redesigned how it fits and attaches to allow for some adjustments - which I guess would not be too hard. I don’t know. Blog out.
