Since our last update, the team has been in Asia working with our manufacturer refining the tooling for Skylock.
The shackle is one of the most unique and important pieces in the production of Skylock. In production forging, a thick rod of 4140 Chromoly steel is heated to 2200°F (1200°C), is pre-bent to the general shape of the shackle, and then placed between two extraordinarily hard steel dies that have the bottom and top halves formed into open faced molds. The hammer (a piece of capital equipment roughly the side of a house) slams the dies closed with forces measured in the tens of thousands of tonnes. Under such pressure, the metal reaches a state called “plastic deformation” and literally bends, compresses and flows into the shaped cavities of the die. For complex, or high-precision forging, multiple dies with successively deeper cavities are used to gradually tease the material into the desired shape.
The forging has intact grain lattice that is flowing and curving to meet the final shape of the part, leading to exceptional strength. Forging is the de-facto standard for creating the strongest metal component possible.
Once the forging is complete, the shackle moves on to a sand blasting station where hard sand is blasted at high speed to grind down the parting lines, and even out the surface for a smooth satin finish, that won’t scrape your bike.
Once the sandblasting is complete, we start the machining process along the tips that interface with the lockbar. Custom fixtures are used to precisely machine the tips. The shackle is flipped several times to achieve the compound curves needed to properly mate the shackle with the locking pins in the lockbar.
Another set of custom fixtures are then used to secure the shackle as it undergoes the electroplating which is a process where the shackle gets its matte nickel coating for corrosion resistance.