Calculating bpm from machine sound (not music)
There are two differences between your problem and music beat detection:


The beat in music is a "latent" grid. It's not because a track is at 120BPM that you have exactly 2 notes per second. In music, the beat is more of a lowest common periodicity than an exact pulse train - that's why beat trackers often make octave errors, and also why there is no consensus between human listeners as to what is the BPM of some tracks. Your task doesn't suffer from the same ambiguity because every "hit" counts.
The beat in music rarely changes over time; and when it changes, it is often progressive. As a result, the tempo can be assumed constant over windows of 5 or 6s for music. Judging from the video, you cannot make this assumption; because the "rhythm" here is very irregular; with pauses/breaks, and frequent changes.


Because of these, I fear that all the assumptions embedded into beat tracking algorithms made them useless on your problem. My suggestion would be to just use an onset detector with a high threshold (to make it more robust to noise). The events you want to detect seem to cover a rather wide frequency band anyway and have a fast decaying envelope.

Then, simply measure the time delta between adjacent events (when this delta is too high; consider that this is a pause); and eventually, average this over groups of a couple events.