# Can ISO GPS and ASME Torancing Systems Define the Same Functional Requirements?
## 3 Conclusions  
The challenge is the parallel existence of two geometrical tolerancing systems that are used to control a part size, form, orientation and location deviations. The ISO GPS system standards and National American Standard ASME Y14.5-2018 establish communication protocols between designers, manufacturing engineers and inspection staff that are particularly helpful in a global economy where parts may be designed in one country, produced in another and assembled elsewhere. The proper specification of allowable geometrical deviations is a key issue for successful fabrication of parts that enable the required assembly and performance. Miscommunication during specification and misinterpretation of \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Characteristics**} & \multirow{2}{*}{
\begin{tabular}{c} **ASME** \\ **Indication** \\ \end{tabular} } & \multicolumn{2}{c}{**ISO GPS**} & \multicolumn{2}{c}{**ISO GPS Symbols**} \\  & & **Identical Graph-** & **for Equivalent** \\  & & **Indication** & **Indication** \\ \hline size for shaft & \(\varnothing 20\)\({}_{-0,2}^{0}\) & \(\varnothing 20\) -0,2 & 0 & \\ \hline size for hole & \(\varnothing 20\)\({}^{+0,2}\) & \(\varnothing 20\)\({}^{+0,2}\) & \(\varnothing 20\)\({}^{+0,2}\) & \(\varnothing 20\)\({}^{+0,2}\) \\ \hline straightness, flatness, cylindricity & \(-\)\(\bigtriangleup\) & \(-\)\(\bigtriangleup\) & \\ \hline roundness & \(\bigcirc\) & \(\bigcirc\) & CB0,25- G50- \\ \hline perpendicularity, parallelism, angularity for integral line/plane & \(\bigcirc\) & \(\bigcirc\) & \\ \hline perpendicularity, parallelism, angularity for derived axis/plane & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) \\ \hline position (only for derived axis/plane) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) \\ \hline profile of a line, profile of a surface (only for integral features) & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) \\ \hline profile of a line profile of a surface & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) \\ \hline run-out & \(\bigcirc\) & \(\bigcirc\) & \(\bigcirc\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of ASME Y14.5 and the ISO GPS system symbols meaning. symbols given in the technical product documentation can result in controversy during outsourcing and verification of parts, and can cause expensive scraps or reworks. It should be noted that the same concepts or rules that exist in National American Standard ASME Y14.5-2018 and in the ISO GPS system standards are called by different names or coded graphically in a different manner. For example, feature control frame (ASME Y14.5) versus tolerance indicator (ISO GPS), basic size (ASME Y14.5) versus theoretically exact dimension (ISO GPS), true position (ASME Y14.5) versus theoretically exact position (ISO GPS), true profile (ASME Y14.5) versus theoretically exact profile (ISO GPS), maximum material boundary (ASME Y14.5) versus maximum material condition (ISO GPS), etc. In this paper, to make it more clear, in most cases only the ISO GPS system terms have been used, even in the case of discussion of dimensional and geometrical tolerances specified according to ASME Y14.5. The problem of transformation from ASME Y14.5 specifications to the ISO GPS system specifications has been discussed in the paper in regards to selected cases for size, form, orientation and location specifications. Many people believe that specifications in both systems are identical because both systems have the same symbols for form, orientation, location and runout tolerances. This is not true. Many default rules are different. Moreover, there are cases when the same graphical symbol is used in the ASME standard and in the ISO GPS system but have different interpretations--sometimes the same symbol recalls different extracted features to which a tolerance is applied. This is a danger for less experienced designers, manufacturers and quality staff. Table 1 was developed to summarize the question of differences and similarities between ASME Y14.5 and the ISO GPS system tolerancing tools.