I've discovered a problem with MI's tools (which also applies to EI's tools :p). Previously, the diesel and steam tools were not enchantable since they come by default with silk touch, and in the case of diesel tools, fortune as well. The new data driven enchantment system kinda messes with this, since it uses tags to determine which items can have certain enchantments. These tags are automatically applied to the different tool tags, so that means these enchantable tags are applied to the steam drill, diesel drill, and diesel chainsaw. I'm not sure how we can go about fixing this, since other mods may also apply their enchantable tags to tool tags, and thus their tags get added to the tools as well.