The Grantham grafting tool can be used to make the 4 vertical cuts (figure 3)
Choose a smooth, straight piece of scion wood that is approximately the same diameter as the stock and about 6 inches long. It should have two or three plump buds, one at each node. Use a sharp knife to cut the scion on four sides. Start the cut about 1 1/2 inches from the bottom end and move the knife away from you (figure 4).
Make cuts through the bark down to the wood but do not remove too much wood. The end view will be square as shown in figure 2. Do not completely "skin" the scion. Leave four thin slivers of bark and cambium at the corners.
Pull the four flaps of bark down 1 1/2 inches on the stock. This is why the graft is sometimes called the banana graft (figure 5).
Remove the inner stock wood and be careful not to damage the 4 flaps on the stock (figure 6).