A narrow flat-edged hand chisel used primarily to cut grooves, leaving a recognizable flat-bottomed channel of approximately square section.
Ugnetto is a hand tool normally struck with a hammer. Its cutting edge resembles a narrow flat chisel. Le voci del marmo identifies its primary purpose as excavating grooves, leaving a characteristic flat-bottomed channel with a roughly square cross-section.
Etymology
Italian workshop term.
Sculptor Notes
Do not confuse Ugnetto with Unghietto. The two names are similar, but the source treats them as distinct tools. The ugnetto is characterized here by its narrow flat cutting edge and groove-making function.
References
https://levocidelmarmo.sns.it/scheda_oggetti_relazione.php?denom=ugnetto&id=6