Bought a $40 'universal' tool setter for my home shop mill, it was off by 0.002" out of the box. Worth trying to calibrate or just junk it? | CNC Operators - Vivisector
Honestly I'd try to fix it. Two thou is a lot but it's a known error, so you can work with it. I mean, you could shim it or adjust the offset in your control. It's not like @nancy326's scanner where the problem just gets worse the more you mess with it. A tool setter is just a physical switch, so there's a real chance you can get it right. Junking a $40 part feels like giving up before you even start.
Tried calibrating my old scanner last week and ended up yelling at a paper jam for twenty minutes. My ego definitely took more damage than the machine. I feel like some projects exist just to teach us humility.
Ask if you've already taken it apart and checked the actual switch mechanism inside. I've messed with a couple of these cheap tool setters and sometimes the issue is just a burr or a tiny piece of debris throwing off the plunger alignment. Before you mess with offsets or shims, pop the cover off and see if the plunger moves smooth and clean, you might be able to fix it with a file or some compressed air. It's worth ten minutes of your time before you decide it's junk.