Greetings members. I am wrapping up a polish underfolder build and I had a legality question. I know the stock has to be permanently fixed open, and I was wondering if this would be a legal way to do it. In my research online I found a guy who had an easily reversible method, essentially it is a piece of copper pipe halved and clamped around the center support pin to prevent the button from being depressed. See pic below. I was wondering if using this same method with steel pipe and welding the halves together would be considered a legally fixed stock. Any input appreciated, thanks in advance.