The following is based on an analysis of wills for Old Chester County PA. POD's are based on where the will was filed, which may or may not correspond to where the person was living at the time of death. A summary of the key Porter wills is provided at: Notebook:Porter_Family_on_the_Octoraro.
Three wills are of interest for this analysis:
The will of James Ogelbay (Ogleby) includes a bequest to his daughter "Violet Porter". It does not identify her husband by name. There are three lineages on Ancestry which show a Violet as the daughter of James Ogelbay (various spellings). Two of those lineages identify her as the wife of Nathaniel Porter. Nathaniel's death date of 1749 is known from cemetery transcriptions of [[Place:Black's Cemetery, Adams, Pennsylvania, United States|Blacks Cemetery, Adams County PA] (Cumberland Township). A Violet Porter (d. 1753) is buried in the same cemetery along with a William Porter (d. 1753).  It is likely that Nathaniel and Violet buried in Blacks cemetery are infact husband and wife, and that she is the daughter of James Ogelsby (who, from the date of his will written November 1752) probably predeased his daughter.)
A will for Nathaniel Porter of Adams County has not as yet been recovered. His sons are commonly identified on Ancestry Family trees as
Wills have been recovered for James, William and John Porter, believed by many to be sons of Nathaniel and Violet. The will of William Porter identifies brother Hugh Porter and brotherinlaw Rees Price as the "overseers" of his estate. James, William and John each have a daughter Violet named in their will. Violet is a relatively uncommon name in the area, and its use in these three families may indicate a close family relationship. It seems reasonable that these three daughters were named after Violet Oglesby Porter, wife of Nathaniel Porter, and said to be the mother of James, William and John Porter
The granson John Porter may be the son of either William or Thomas, or that of an unnamed son who predeceased him. The other grandsons are presumably the children of unnamed daughters. Conceivably these could be sons of daughter Violet by different husbands, but in that case it seems unlikely that they would have named all three "John". More likely, these are children by unnamed daughters, perhaps deceased, or perhaps simply not identified. The fact that the only grandchildren identified in John's will are named "John", suggests that he is focusing on his namesakes, and not trying to be comprehensive in his bequests. Daughter Violet, since she is explicitly identified, and no last name is given, may be unmarried.