Blade Shooters Maelstrom power requires special modifications and blade construction not possible through other methods. The Blademill enables rapid and continued production of blades inside Blade Shooters.
”
~ Official BMC description
The Blademill is a Special Building that allows research of the Blade Maelstrom upgrade for the Tack Shooter, it costs 14,000 to build, it takes 48 hours to construct and gives 500XP when construction is finished. It consumes 40 and a 1x1 tile space. It requires Level 18 to unlock.