High field tokamak machines have established by now a long standing tradition both in the United States and in Italy. Also Japan has tackled this issue with the TRIAM machine. From ALCATOR A at MIT to FT at ENEA, Frascati, ALC C, FTU, ALC C MOD and now the study of IGNITOR.The main motivation, behind this choice, has been the attempt to find a shortcut to explore the physics of regimes with a high nτT parameter in limited size experiments and therefore without undergoing excessive costs. The line chosen has privileged high plasma densities and therefore has requested very high magnetic fields in exchange for reduced size of the plasma volume. What has to be paid is a very accurate, difficult and sometimes tricky engineering.The paper intends to review and present some of the most interesting solutions in the field of mechanical and electrical engineering which have been adopted by the designers.