If your soldering is perfect; then you don't need threads; right on the Heym; the shoe lumps are hard soldered (probably silver brazed) directly to the barrels. I prefer to thread and have used tin solder sometimes; usually not. I do not use hard (braze type) solder; it takes too much heat and is hard to remove if you ever need to. I have used Brownells hard solder on the regulation wedge but that stuff is hard to use.