The nuance of comes 片手間 through in the following sample sentence:
彼は大工ですが片手間で地元のクラブでドラムを
演奏します。Kare wa daiku desu ga katatema de jimoto no kurabu de doramu o ensō shimasu.
He’s a carpenter, but he plays drums at a local club in his spare time.
The sentence suggests that the protagonist makes his living from carpentry. If he earns any money for drumming, it must be less than what he earns from his job.
A breakdown of the kanji in the sentence:
彼 (kare: he)
大工 (daiku: carpenter) big + workman
片手間 (katatema: in one’s spare time, on the side, odd job)
one-sided + hand + interval
地元 (jimoto: local) locality + origin
演奏する (ensō suru: to play music)
to perform + to play music
