With the crane, it could probably have infinite lift strength and still not be broken. However, game balance is always good to keep in mind. I'm also not entirely sure how a crane would be able to displace sideways without treading on the other tools' abilities.
I think the shovel having an element of RNG is fun, as long as it's somewhat predictable. Maybe a system could be implemented where the shovel will displace to the right if the last horizontal movement you made was right, and left if you moved left? It could still be random whether it moves 1 or 2, but you would have a way to herd the pebbles a little bit better.
A further thing could be that the vertical movement determines how large the number is, although that would remove the RNG.