Motorcycle Frame Fabrication Parts

MOTORCYCLE FRAME FABRICATION PARTS FOR CUSTOM BUILDS

Every custom build hits the same point: the stock frame does not have a hole, thread, or mount where you need one. Frame fabrication parts are how you solve that problem without starting over. Threaded bungs, mounting tabs, axle plates, sissy bar rod ends, solo seat mounts, and fender strut kits give you the raw material to build mounts and brackets onto a frame exactly where the build needs them. Lowbrow Customs bungs and tabs are made in Ohio from 100% US steel, in individual packs and assortments from 4 to 120 pieces depending on what the project calls for.

BUNGS AND THREADED INSERTS

A bung is a threaded steel or aluminum insert that welds into frame tubing, sheet metal, or any fabricated surface, giving you a clean, permanent thread point that will not strip out under torque. The collection covers several bung profiles for different applications:

• Coped Bungs: Machined with a saddle profile that fits flush against round tubing so the weld sits correctly without gaps or air pockets. Available in 5/16-18 and 3/8-16 thread in multiple lengths. The go-to bung for any mount going directly onto a frame tube.

• Tophat Blind Bungs: A flanged profile that mounts on flat surfaces and sheet metal where a counterbore flush finish is needed. Available in steel and aluminum, in 3/8-16 and 5/16-18 thread.

• Counterbore and Full Radius Bungs: Counterbore bungs allow the bolt head to sit recessed flush inside the bung. Full radius bungs have a round outer profile for tubing applications where a smooth exterior matters.

• Riser Bungs: 1/2-13 threaded steel riser bungs for welding handlebar riser mounting points into custom top clamps and trees.

• Bung Assortments: 12-piece assortments cover a range of sizes for shops and builders who want a shelf stock of the most common bung profiles. Browse the dedicated motorcycle bungs collection for the full range.

MOUNTING TABS AND FRAME HARDWARE

Tabs handle everything from fender strut mounts to ignition switch brackets to brake stay mounts:

• Mild Steel Mounting Tabs: Tab #4 and Tab #5 in 3/16-inch mild steel, sold in packs of four. Easy welding steel designed for MIG and TIG. These are the general-purpose shop tab that ends up on almost every custom build.

• Rubber Mount Triangular Tabs: Triangular profile tabs with aluminum washer for rubber-mounted applications where vibration isolation between frame and component matters.

• Ignition Switch Tab: Weld-on 13/16-inch ignition switch mounting tab for custom frame builds where the switch needs a clean, purpose-built bracket.

• Solo Seat Spring Mounts: Weld-on solo seat spring mounts machined with a 1-inch coping to fit standard frame tubing. Pairs include leather washers and cotter pins to prevent spring squeak.

• Fender Strut Kits: Lowbrow Customs DIY fender strut mounting kits for custom chopper and bobber fender setups. Browse motorcycle fender mounts for the complete fender hardware range.

AXLE PLATES AND RIGID FRAME HARDWARE

• Rigid Frame Axle Plate Set: OEM Harley-Davidson style axle plates for custom hardtail and rigid frame builds. The correct way to finish a rigid rear section with proper axle retention and adjustment.

• Gasbox Axle Plate Threaded Bungs: Threaded bungs specifically sized for Gasbox axle plate applications on 1936 to 1957 Harley-Davidson Big Twin rigid frames.

• Rear Chain Adjuster: Lowbrow Customs universal rear chain adjuster for 3/4-inch axle custom hardtail builds where adjustable rear axle position is needed for chain tension.