Can you elaborate a bit more on the stopple that goes in the bottle mouth. I used the same idea but without the spring loaded idea. I machined a tapered tip with the back threaded to screw on the bolt. I tumbled about fifty so far but i did overtighten one hutch and broke it. Do you have any movement with the weight of the copper in the bottle? I really like your idea with the spring. Can you show a breakdown some time how it's assembled.