It hangs on an axis point. The axis opens up, and reveals a hanging scroll. This might take a little extra imagination, but I believe in you.
For 掛 you'll want to think back to the word 掛ける, then shorten it and shove it into the kanji half way (the かけ part at least). For 軸 that's the reading you learned with the kanji, so at least you have that to work off of.
I want Aya to paint a picture for the hanging scroll.