ISO STEP (Standard for the Exchange of Product model data) files are widely used in the manufacturing industry to exchange 3D design data. Extracting features from these STEP files can be a powerful tool for various applications, such as computer-aided design (CAD) and computer-aided manufacturing (CAM). The extraction of features from ISO STEP files can facilitate various tasks including automatic recognition of standard components, identification of geometric relationships, and generation of interactive visualizations. This enables users to streamline their design processes, improve collaboration, and enhance overall productivity. Hence, data extraction from STEP-file is becoming essential for automated manufacturing of parts particularly cylindrical ones. The paper presents methodology to extract all the related entities, vertices and cartesian points of the cylindrical parts. An integrated computer package is developed to analyze and extract the geometrical data that define parts' feature for cylindrical parts. A methodology to extract all the geometrical details of the parts stored as STEP file AP203 is proposed. To check the suitability of the proposed methodology and validate the computer package, several cases covering all the features that may exist in any cylindrical parts were considered. The studied cases were created using Inventor package version 2023.  A software package written by Microsoft Visual Studio 2022 - C# is designed, tested, and applied to the considered cases. The system proved capable of getting all the geometrical details for internal and external surfaces of straight cylinders, tapered cylinders, conical surfaces, recesses, fillets, internal drill, Chamfering and undercut. Several case studies were considered. Some are given in this paper. The obtained results verified the success of the developed software.