Rashi on Judges
The hilt. The iron into which the blade is inserted, called 'hulot' in old French. This balances the sword in its scabbard.
Metzudat David on Judges
Also the handle: so that he would die immediately without screaming. it was stuck deep.
Metzudat Zion on Judges
The handle: this is the handle of the sword that it is based on to do its job