Holmes doesn't actually thump his stick on the pavement in front of the pawnbroker's shop. The story does not mention this action. However, Holmes does use his stick in a very specific way to help solve the mystery.
Here's what happens:
* Holmes and Watson visit the pawnbroker's shop to investigate the disappearance of the "Red-Headed League" member, Jabez Wilson.
* Holmes notices that Wilson's office floor is unusually worn, specifically in a small patch directly in front of the safe.
* He uses his stick to tap out a series of precise measurements on the floor.
* He then uses his stick to "beat" on the floor in a specific rhythm and pattern.
* This "beating" reveals a secret tunnel beneath the office floor that was used by the criminals.
Therefore, Holmes's use of his stick is more about using it as a tool to discover the hidden tunnel, not as a dramatic gesture in front of the pawnbroker's shop.