Home in and Knuckle down

Home in verb - Direct onto a point or target, especially by automatic navigational aids.

Knuckle down and home in are semantically related. in aim attention at topic. In some cases you can use "Knuckle down" instead a verb "Home in".

Knuckle down verb - Work very hard, like a slave.

Home in and knuckle down are semantically related. Sometimes you can use "Home in" instead a verb "Knuckle down".