round gimlet
A hand tool with a spiral tip used for boring holes in wood; a type of auger.
The carpenter bored a hole in the board with a round gimlet.
Standard kanji spelling; the characters mean 'round' and 'gimlet'.
Variant spelling using 丸 (round) instead of 円; less common but still encountered.
Compound of 円 (まる, 'round') + 錐 (きり, 'gimlet'). The reading まるぎり is a straightforward kun'yomi combination.