Assembly considerations machine tools

The assembly accuracy between column and bed is an important consideration in machine tools because it directly affects the machining accuracy. Though each column surface and bed adjoining each other... 

Principal use of threaded joints is in sizes 2 in and smaller, in metals for which the most economically produced walls are thick enough to withstand considerable pressure and corrosion after reduction in thickness due to threading. For threaded joints over 2 in, assembly labor size and cost of tools increase rapidly. Careful alignment, required at the start of assembly and during rotation of the components, as well as variation in len h produced by diametral tolerances in the threads, severely limits preassembly of the components. Threading is not a precise machining operation, and filler materials known as pipe dope are necessary to block the spiral leakage path. 

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