The MiniPCB Version 2
If you are looking for information on an earlier version of the MiniPCB that page can be found here.
The image below shows an OnStep built on a MiniPCB Version 2 (scroll down to see the bill-of-material.) This PCB is designed to fit inside a commonly available aluminum case. Though the case flat end caps will need very careful need drilling, cutting, and filing to provide openings for the various connectors. If a 3D printer is available plastic end caps can be printed with little time or effort. This is the case the MiniPCB Version 2 is designed to fit: Aluminum Enclosure Electronic DIY PCB Instrument Project Box Case(100x71x26mm)
Please feel free to contact me for cost/availability and detailed info. on how to order a kit containing most parts to build the controller including the case, end caps, and heat-sink shims for SSS TMC2130 stepper drivers.
The very affordable EasyEDA service can be used to order this version of the PCB (or obtain the Gerbers.)
OnStep can use different "pin maps" and this PCB was designed for the Config.MiniPCB.h wiring!
Whatever you build use an appropriate DC rated fuse (current rating depends on stepper drivers/motors/etc.)