“Effect of Pre-hole Diameter on Bushing Dimensions for Friction Drilling Process of A6063-T6 Aluminum Alloy” (2021) Journal of Al-Rafidain University College For Sciences ( Print ISSN: 1681-6870 ,Online ISSN: 2790-2293 ), 39(1), pp. 373–387. doi:10.55562/jrucs.v39i1.218.