I am designing a math font with the usual math encodings (ot1, oms, oml, omx, msam, msbm) and am trying to get the math accents correctly. I already found out that the correct accent position is done with the skewchar and kernings with the skewchar. But I am still wondering:
cmsy10 has its skewchar at the code '060 = 48 and cmmi10 has its skewchar at the code '177 = 127. The skewchar of cmsy10 is a prime (') with the width 275/1000 whereas the skewchar of cmmi10 is a tie (◌̑) with a width of 277/1000. What is the connection of the skewchar with the accent positioning? (Is the width the only important thing of the skewchar?) How can TeX tell whether T' means a kerning between "T" and "prime" or a kerning between "T" with the skewchar?