U.S. Built Custom Bicycles in Titanium and Titanium-Carbon Mix
Frame Tacking: Hidden Precision
Most of Seven’s framebuilding efforts are invisible. That’s okay. We know what we did.
Tube specification accuracy, material cleanliness, as-machined frame alignment, joint fit-up, etc. These types of hidden precisions throughout our tack welding process are fundamental to building a strong straight frame. Equally important, these obscured cornerstones provide the beginnings of Seven’s legendary ride.
Stef understands these nuances better than most. She is part of our Special Projects Team. With nearly 30 years of frame welding experience, she is one of Seven’s Master Welders. Here Stef works through the tack welding procedure for our SOURCE Endurance Race Gravel project bike.
Stef tack welds the seat tube and bottom bracket assembly, the first phase of frame tacking. A tack is a small weld that holds the tubes together. These steps allow her to remove the assembly from the frame jig and weld the frame without fixture hindrance.Stef checks the accuracy and alignment of this seat tube assembly. The bottom bracket is the foundation of the frame. If, after welding, the seat tube is not perfectly aligned to the bottom bracket, the frame will not be straight and will not ride true. Working precisely now and at every step makes perfect finished frame alignment possible.Stef welds the internal guides and ports. Some internal housing routing welds are done before tacking and some after. It’s complicated.Stef modifies each of her welding helmets and shields, making them as light as possible. This subtle mod allows her to work faster and with higher precision. Make no mistake: Stef’s weld quality is second to none. Regardless, even after 30 years, she constantly refines her craft.Stef tacks the down tube in place. The coped tube fits its mating tube within a few thousandths of an inch — about the thickness of a human hair. This invisible accuracy helps us build straighter frames that roll faster and live longer.Stef tack welds the top tube and seat tube. The titanium weld area is cleaned and prepared in a four-step process. This is yet another unseen tedious procedure that set the stage for the strongest, most durable welds possible.
