Hi there Seems if you allow jackhammers to stack, if the jackhammer runs out and you have another one in your inventory you can right click it and it stacks with the other one and becomes band new.
Also if you allow Diving Fins, Mask and Diving Tanks to stack, it alters the selling stacks at the fishing village. I had mine set to 10, then players were able to purshace 10 at a time for like 35 scrap. Which is super easy HQM for cheap.