FingerTech NightWing Undercutter Weapon Assembly The FingerTech NightWing undercutter is the complete weapon assembly mechanical stack from FingerTech’s renowned NightWing 3lb kit — sold separately so you maintain your bot, or so you can drop a proven, competition-ready spinning weapon into any 3lb build. Whether you’re building a NightWing from scratch, designing your own custom undercutter chassis, or replacing a damaged weapon system, this assembly kit gives you everything you need to get spinning (electronics and blade not included). A Weapon System Refined in Combat FingerTech has refined this undercutter weapon system over years of competitive combat. The 3/4″ weapon shaft is supported by an SCE128 high-performance roller bearing that dissipates impact forces over a large area, keeping the weapon spinning reliably hit after hit. A flanged bearing at the opposite end of the shaft completes the support stack. The result is a weapon system that’s extremely robust without being overbuilt or overpriced. How It Works A Grade 8 hex bolt transmits torque and clamps the entire weapon stack together through a threaded bore in the custom 42T timing pulley. The pulley is custom-made for this assembly with a 5/16-24 threaded bore — it’s not a standard pulley swap. Note that the standard FingerTech 42T pulley will not work in this application! UHMW spacers and a bearing block keep everything aligned and absorb shock, while a lasered steel hex star and aluminum disc hub provide a solid, repeatable mount for your weapon disc. What’s Included SCE128 high-performance roller bearing FR1810zz 5/16″ flanged bearing Custom 42T-5/16-24 threaded-bore pulley Lasered steel hex star aluminum disc hub Aluminum tube spacer, UHMW thick thin spacers UHMW bearing block four #6×0.75in thread-forming mounting screws 5/16 x 2.00in Grade 8 hex bolt flat washer Four 6-32 x 3/8in button head screws 5/64in hex key Total assembly weight: 133g (4.69oz). Weapon disc and electronics not included. Disc Options This assembly is designed to pair with a 10in weapon disc. The FingerTech NightWing AR500 Weapon Disc is the standard pairing — AR500 steel for maximum momentum and big hits. On a 3S LiPo this weapon supports up to 8,000 RPM, delivering a tip speed of 240mph. It can also run on 4S if you’re using a smaller diameter disc for faster spin-up and more control. Custom Chassis Builders Want to design your own undercutter around this weapon stack? Use 3.18mm (1/8in) top and bottom plates with 30.35mm (1-3/16in) tall walls, and space the motor axis 46.13mm (1.82in) from the weapon axis. Pairs with the FingerTech 3lb Undercutter Electronics set for a complete drivetrain and weapon power solution. Safety Warning: Spinning weapons generate extreme kinetic energy. Always engage a weapon lock and test only within a secure arena or test box. Never operate a spinning weapon in an unsecured area. ItGresa Combat Robotics Safety Guide FingerTech Combat Robot Safety Guide FingerTech Test Box Build Instructions (PDF)
