Changing Nafuda after gradings - Dojo Nafudakake

We are often asked how can we change the position of the nafuda after gradings.
I thought a picture of the nafudakake in section would help.

Above is the general layout of a dojo nafudakake showing the head, mid-rail and cill sections.
I have "shunk" the height so you can see all the sections, but you will notice the nafuda sits in a shallow rebate and the head has a much deeper rebate. This allows for the nafuda to be raised into the head and lowered onto the cill and it will not fall out.