Goes through three stacks of chalk (7)
I believe the answer is:
needles
'stacks of chalk' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for needles that I've seen before include "landmark" , "passes through" , "Rocks off Isle of Wight" , "Is annoying" , "Pins and - -" .)