Laurence Edwards shows how to fit a National frame into a Langstroth poly hive by screwing a support into the side to extend the frame rest. Once brood emerges, you remove the screws and swap in a standard Langstroth frame. Useful for making nucleus colonies and overwintering.
You can't add a National frame into a Langstroth hive because the top bar isn't long enough. It just falls down to the bottom. Here's a hack to make it fit. Take a couple of screws and line up all of your frames and then screw into the side of the poly hive to extend the frame rest. This will give you a really easy position to rest that National frame so you can add it into your Langstroth hive. Once all of the brood has emerged, you can remove the frame, take out the screws, and add in a new Langstroth frame. But it's a great way to transfer from National over to Langstroth if you're looking at making up some nucs to overwinter.
