Melt electrowriting (MEW) is a high resolution material extrusion based additive manufacturing process with the unique capability to produce micron to sub-micron diameter fibres and control their deposition in three dimensions. Here, we detail the design, development and build of a custom MEW printer which has full integration between all core components. We detail the design and build of the motion system, print head (including heaters, extrusion system and high voltage power supply) and safety systems, and explain how these are integrated via a central control unit to provide pre-programmed dynamic control over printing variables allowing the fabrication of a range of advanced material designs with applications in the fields of tissue engineering, regenerative medicine and beyond. We discuss the various approaches which may be used for each system within a custom MEW printer, providing an insight into how it may be designed depending on the specific requirements of the end user. Finally, we demonstrate the capabilities of this printer by producing tissue engineering scaffolds with various architectures. This work aims to make MEW technology more accessible by both informing others interested in developing similar custom devices, and additionally, by providing an insight into the inner workings of MEW technology for practitioners in the field.