Fabrication Parts for Harley Big Twin Custom Builds. The Big Twin Fabrication Parts collection at TC Bros is your go-to source for the essential components needed to create one-of-a-kind Harley-Davidson Big Twin motorcycles. This category includes a wide range of builder-friendly products, such as weld-on brackets, mounting tabs, and DIY-friendly kits, all crafted to help you bring your custom vision to life. Designed for Softails, Dynas, and Touring models, these parts are built with precision and durability to meet the demands of professional fabricators and garage builders alike. With TC Bros' industry-leading fabrication components, you can trust your build will be as functional as it is head-turning.