I would like to modify a UK National hive to take FLOW frames. Has anybody successfully converted both a National hive and the FLOW frames to fit.
Ozbee, I only run langstroths but did a quick search here and several good comments about the Flow-Hive to National Box. So go to the main section here n type in " Flow to National conversion" … You should come up with some good info.
Good luck n happy beekeeping from the States, Gerald.
http://forum.honeyflow.com/t/uk-national-hives/3150/3
There’s Video Here by @DextersShed
I hope he’s OK?
He’s disappeared from the other two beekeeping fora he frequented
I’m his friend on Facebook - He seems OK - I think he has just gone into Cluster like the bees 
The frames can be modified to fit in a National sized box. In the past I have mixed National sized boxes and Langstroth sized boxes by building an adaptor and then using a Langstroth lid on top of the Langstroth super. I don’t know dimensional lumber in the UK, but here a one by two (3/4" x 1 1/2") is what I would use. Cut two the length of the Langstroth and these will go on the sides of the Langstroth (just friction fit when we are done) and then two the width of the National. Then nail down from the ones on the Langstroth sides down into the ones that are now on the ends of the National. The National length ones block the excess space on the bottom of the ends of the Langstroth hive, while the Langstroth length ones block the gap at the top of the National hive. Easier to build than to explain. Easier to explain if I knew the metric measurements for all those things…
OK. The two “National length” boards are 460mm long. The dimensions of the board otherwise just have to be at least 19mm thick to cover the gap. The two “Langstroth length” boards are 505mm long and at least 19mm thick. Lay the National length boards on the floor and put the Langstroth ones on top, line up the corners to make a lap joint and nail down through the Langstroth ones into the National ones and you’re done (or drill pilot holes and screw them). To use put this on top of the top National box with the National length boards down. Put the Langstroth box down in between the Langstroth length boards. Voila!
Much less work than disassembling the frames to make them into National frames… but it requires a Langstroth cover.
That was assuming a ten frame Langstroth box, not an eight frame.