JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING, cilt.48, sa.6, 2026 (SCI-Expanded, Scopus)
Chatter significantly limits productivity in deep-hole boring operations. Identifying stable combinations of spindle speed and depth of cut through trial-and-error approaches is both time-consuming and costly. Therefore, a reliable stability prediction that directly incorporates tool dynamics and cutting mechanics is needed to reduce the risk of chatter. This study presents an experimentally grounded stability prediction approach for a commercial boring bar and quantifies how overhang distance and insert geometry shift stability limit during the boring of Ti-6Al-4 V alloy. Frequency Response Functions (FRF) were obtained via hammer testing by using three overhang distances (LO = 125, 160, 195 mm), and cutting-force coefficients were calculated by using the measured cutting forces. These inputs were implemented in CutPRO to generate stability diagrams. The predicted stability limits were subsequently validated through cutting experiments and detailed surface inspections. Results showed that increasing overhang distance reduces the stability limit by more than 90%. At constant overhang, increasing the cutting-edge angle (Kr) from 70 degrees to 90 degrees improves the stability limit by approximately 60%, whereas increasing the insert nose radius (R epsilon) from 0.4 mm to 2.4 mm leads to highly unstable conditions across all overhang distances. These findings provide practical guidance for selecting overhang distance and insert geometry to maximize chatter-free cutting conditions.