Today, we continue our deep dive into The Argonaut Way—our proven process for building the ride of your life. This time, we’re exploring the exciting art of Frame Fabrication: how our approach has evolved and what we’re doing today to push carbon fiber bicycle manufacturing forward.
What Does It Mean to Fabricate a Frame?
You might wonder: Isn’t high-pressure, rigid mandrel molding in layup where the real frame building happens? While layup is crucial—giving us the most control over carbon fibers and shaping how individual parts function together—it’s during frame fabrication that our vision for ultimate ride quality truly takes form.
From Mold to Perfection
Though our molded parts are free from surface voids, they’re not immediately ready for assembly. As the pre-preg carbon plies bake, resin flows between fibers, bonding layers into a solid piece. Some resin, however, collects at the mold seams, creating a byproduct called resin flashing. Our first step in frame fabrication is deflashing these parts to achieve the perfectly smooth curves you expect on a finished Argonaut bike.
Precision in Sub-Assemblies
Once deflashed, the parts move to our trim shop, where we assemble the frame in carefully controlled stages. We begin with sub-assemblies to ensure maximum precision, guaranteeing that the complete bike rides exactly as we designed it in the layup stage.
The first sub-assembly step involves bonding our titanium hardware—such as the RM3’s drive-side dropout threads, headset cups, and T47 one-piece threaded bottom bracket insert. Before bonding, each titanium piece undergoes meticulous preparation in our trim shop. Thanks to our in-house Haas CNC milling machine and dedicated machinist, we create all our own complex tools, ensuring every measurement is exact. For example, when facing and reaming a head tube to match a rider’s specifications, we design our own precision tools to improve both accuracy and efficiency.
The Art of Carbon-to-Carbon Bonding
With titanium bonded in, we turn to one of the most critical aspects of frame fabrication: bonding carbon to carbon. Our trim shop’s Laguna CNC machine precisely chamfers the interior surfaces of our long tubing to match the tapered lugs of our junction pieces. This creates what’s known as a scarf joint—a perfectly tapered intersection that controls the amount of epoxy used for bonding.
Our aerospace-grade epoxy forms a uniform application throughout the junction, ensuring a consistent flex pattern across part. This prevents dead spots in the frame, maintaining a lively, responsive ride. Unlike mass-produced carbon bikes, which often trade ride quality for production speed, our bikes retain their soul—providing a connection between rider and machine.
The Seat Sub: The Heart of the Frame
Before final bonding, we continue refining sub-assemblies. With titanium bonded to carbon, we construct the seat sub—the critical centerpiece of the frame. Using geometry drawings confirmed with the client, our technicians measure, cut, chamfer, and prepare the seat cluster, bottom bracket cluster (now with the T47 titanium insert), and seat tube.
The seat sub’s accuracy is about more than just geometry—it defines the entire ride experience. As one of the bike’s three main contact points, the saddle translates road feedback, wheel response, and frame stiffness felt through the connection to the seatpost directly to the rider. Every Argonaut bike is built with this relationship in mind.
Final Assembly and Alignment
While the seat sub takes shape, we bond dropouts into the chainstays, completing half of the rear triangle and moving into the final stages of fabrication. Now, with three anchor points—head tube, seat sub, and chainstays with dropouts—we establish the frame’s final geometry.
Using the fit data gathered earlier, we translate these specifications into 2D engineering drawings. Our builders then use Cobra Framebuilding jigs to set up each frame, ensuring precise alignment in all planes with a dry fit. Once the Cobra jig is set, we can accurately measure exactly where to cut and chamfer the remaining long tubes for the perfect fit ahead of the final bond.
After bonding each part into its place in the whole, we conduct one last alignment check on our granite surface plate before the frame moves to paint prep. This isn’t just about checking lengths with a ruler—we mount the frame in a specialized tool that supports it at the bottom bracket, allowing us to measure straightness with unparalleled accuracy. Thanks to our sophisticated measurement techniques and innovative manufacturing strategy, our frames are straighter—and therefore more efficient and enjoyable—than anything else on the road.
The Road Ahead
From individual parts to a fully formed frame, our fabrication process is a masterclass in precision and engineering. Stay tuned next week as we explore paint design—why we use so little, how we bring your vision to life, and how Argonaut blends engineering with art.