Amyloid oligomers have been widely implicated as primary cytotoxic intermediates; however, their selective and potentially scalable production remains challenging due to rapid fibril amplification. Here, we demonstrated that sustained axial rotation enables programmable mechanochemical control over amyloid pathway selection without the use of chemical additives. Using a thermal axial rotator, native monomeric hen egg-white lysozyme was incubated at 60°C under quantitatively tunable rotational speeds, thereby creating RPM-dependent hydrodynamic boundary conditions through centrifugal and wall-associated mechanical inputs. A discrete RPM-dependent transition emerged, delineating a low-RPM fibril-amplifying regime, an intermediate transition regime, and a high-RPM oligomer-enriched regime. At lower rotational speeds, aggregation followed a fibril-amplifying pathway characterized by elevated β-sheet content and elongated fibrillar morphologies. At higher rotational speeds, fibrillar growth was strongly attenuated and oligomer-enriched assemblies predominated. Spectroscopic analyses and atomic force microscopy revealed that axial rotation redistributes the amyloid assembly landscape rather than simply suppressing aggregation. Functionally, the RPM-defined assemblies exhibited kinetically distinct seeding behaviors and were associated with differential cellular response profiles in SH-SY5Y neuroblastoma cells. These findings demonstrate axial rotation-mediated hydrodynamic boundary control as a scalable, chemical-free strategy for reprogramming amyloid assembly pathways and producing oligomer-rich assemblies for structural and functional studies.