This wheel shaft holds adjustable guide wheels onto a railroad frog grinder. Each part is loaded with the full weight of the grinder and subject to shock loads.
Stanley Black & Decker used to machine these parts out of a single block of steel. Because of the size of the flange and the length of the shaft, this meant that ~90% of the stock material was wasted in each part. With the help of Markforged engineers, Stanley Black & Decker redesigned the wheel shaft to be a three part assembly. By purchasing an off-the-shelf shaft and key, they were able to easily print the flange on the Metal X. The new assembly passed both durability and abuse drop testing.