The adjustable case preparation tool polymer body has a tungsten carbide blade or blades, an adjustment screw, and a lock nut to secure the adjustment. The adjustment screw bears on a pin, which slides in a tube, which is held by friction fit in the molded or 3D printed body. The screw attaches the tool to a handle, prep center, or rotor. Colors identify calibers, and a tool fits every cartridge in that caliber by interchanging lengths of pins and tubes. The tool can be used with interchangeable spindle sleeves in increments of diameter for a precise fit. The flash hole deburring tool will not enlarge or chamfer a flash hole, and the neck turner will not mar a case mouth. The embodiments work on a case held in a case holder, and cutting stops when the pin through the flash hole touches the solid face of the case holder.