Engraving is the practice of incising a design onto a hard, usually flat surface by cutting grooves into it.
Come Together  is a song by the Beatles written by John Lennon but credited to LennonâMcCartney.
The harmony vocals certainly sound a lot like McCartney. I took the quote to mean that he wasnât singing a duet with Lennon â ie at the same time, as they did on The Ballad Of John And Yoko. The version of Come Together on Anthology 3 shows how it was recorded at first with just Lennon on vocals.