The invention relates to a cutting tool for boring into solid material and rotating, comprising a tool main part (4, 6, 10), said tool main part having: a machining portion (10) with a receiving area for a replaceable cutting plate (12), a tool shaft (4) which is designed to be received in a tool receiving area, and a support portion (6) between the machining portion (10) and the tool shaft (4), wherein the cross-section of the support portion (6) is greater than the cross-section of the tool shaft (4), and the support portion (6) is designed to lie against an end face (28a, 28b) of a tool receiving area (20, 22). The support portion (6) has at least one cut-out portion (8a, 8b), preferably at least two cut-out portions.