Get a handle on something and Knuckle down

Knuckle down and get a handle on something are semantically related. In some cases you can use "Knuckle down" instead a verb phrase "Get a handle on something".

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

Get a handle on something and knuckle down are semantically related. Sometimes you can use "Get a handle on something" instead a verb "Knuckle down".