A thin-walled fuser roll core cylinder assembly permitting fast warm-up times and improved energy efficiency wherein cracking of the thin walls of the core cylinder due to cyclic compression is prevented by redirecting axial stress at the terminus of an axial keyway to a radial direction. The keyway is for coupling the core cylinder to a drive gear. Use of such a thin-walled fuser roll in an imaging system and a process of fusing toner onto a copy substrate using the thin-walled fuser core.