I am not sure who came up with the original 8 frame dimensions in Australia, but the bee space is all wrong which is one of my biggest gripes with it (haven’t seen flow specifically, but 8 frames from other manufacturers).
You shouldn’t be able to fit nearly 9 frames into an 8 frame box, if that were the case I would expect the standard 10 frame box to take 11 frames, which just isn’t the reality. What also amazes me is that it has persisted… Bee space is a known quantity, basic maths will provide the internal measurement for an 8 frame box if you are using 35mm Hoffman frames with correct bee space, I’m intrigued as to how it ended up so much wider than necessary. If you’re manually spacing your frames, it completely defeats the purpose of the Hoffman frame design.
Does anyone have the internal width measurement of the flow 8 frame box? Either in metric or imperial?
-edit-
It appears the internal measurement is here (http://www.honeyflow.com/faqs/flow-hive-frames-weights-and-dimensions/p/175), which is 315mm.
So if the Flow 8 frame box is 315mm, 315mm/8 means that each frame is given 39.375mm.
The internal width dimension of one of my 10 frame AU Langstroth boxes is 370mm (which matches https://en.wikipedia.org/wiki/Langstroth_hive), which is 37mm per frame.
If you’re using the spacing from my 10 frame box in the ‘8 frame’ box, it equates to an 8.5 frame box.
Another way to look at it is if the 10 frame box is 10x35mm with 10mm to each side. If this were the case, the 8 frame box should be (8x35)+10+10 which is 300mm, still 15mm less than the internal width.
A flow frame is 50mm wide, so the maths works in a 10 frame super 7x50mm = 350mm, same as 10x35mm Hoffman frames.