On July 09 1969 The Beatles (minus John) started work on the McCartney composition "Maxwell's Silver Hammer". The first trials for the tune were being worked out earlier in the year in January 1969 via the "Get Back/ Let It Be" sessions at Twickenham studios. The song was later discarded when recordings for the January project moved in mid month to Apple Studios.
Fast forward to the summer of 1969 and the new LP as yet untitled. These sessions in July feature Paul on piano and guide vocal, George on bass and Ringo on drums. Take 05 has survived and is now commercially available on the Apple 3-LP/2-CD "Anthology 3" project. It's interesting for the vocal improvisation from Paul in the third verse as well as the instrumental part of the song. There is also a piano flourish ended. It's good take but more takes would be recorded later in the day until take 21 was chosen as the "best" take with acoustic guitar overdub.
The next day on July 10 1969, more overdubs were added to take 21 with some extra piano bits here and there played by Paul, George Martin adding hammond organ to the original two bar intro which would be edited out of the commercial "Abbey Road" LP version. Other additions included a leslie'd electric guitar from George and Ringo added some anvil hits in the chorus and at the end of the song.
The main lead vocal from Paul was added as well as backing vocals on the choruses by Paul and George and the final "Maxwell Silver Man" end chorus included Ringo as well. Once this was completed, a mono mix of the song appears on the vinyl bootleg "No. 3 Abbey Road N.W. 8" as well as on CD as "Unsurpassed Masters Vol. 5" with both containing the original intro and the take announcement "take 21".