Here is the link to the original post
https://tropicalfruitforum.com/index.php?topic=29250.msg330723#msg330723If you look carefully, you will observe that what you did is not what Sapote did. What you did is what experienced grafters would assume he should have done, which is closer to a veneer graft. What he actually did on the grave part was cut two parallel lines wider than the scion, cut the tops so he could peal the back off. On wood that is pushing the back will slip right off.
The idea is that it would leave the cambium layer exposed over the entire contact area where the back was removed. It was then simply getting the scion which was not cut vey deep to touch the cambium layer and you would get your graft.
My assessment of what you did is your scion (coffin) is cut too deep and your root stock (grave) too shallow. So the coffin is sitting on the grave not lowered into it. It could be a wonderful veneer graft and take just fine but it was not what Sapote was suggesting.
If you have another scion it may be a good experiment to try his grave and coffin method as a comparison. ... I hate that name.
The method is counter intuitive for many folks who have watched a lot of grafting videos but if you do bud grafting (where you peel the bark back, you will see exactly what he is doing. For the rest of us, we keep trying to improve on his technique for example the post below was from someone who tried and was partially sucessful and found a way to make it better.
https://tropicalfruitforum.com/index.php?topic=29250.msg392960#msg392960