After several years of research, I'm happy to share with you the way I achieve the best results when fixing the handle in the hoe's eye.
This technique comes from three simple observations:
wood "moves" according to hygrometry. My hoes all came unfixed when we went through a period of heatwave and drought. This is because wood shrinks.
fat reduces friction between two elements.
a tool like a hoe, whose weight is not balanced on both sides of the eye like a pickaxe, is harder to handle. This is due to the overhang induced by the blade. This does not allow the handle to be plumb and slip into place.

To fit your hoe properly, you need to simulate a dry weather, oil the friction parts, and apply a counterweight to the opposite side of the hoe blade to ensure that the handle fits plumb.

The hoe is a reincarnated Cocconato hoe. A rare model that was no longer produced, it has been updated using the same manufacturing technique as the original: the hoe is forged in one piece with a powerhammer. Its surface finish increases strength and reduces the "earth sticking to the tool" effect. Available here: https://lafrontiere.fr/boutique/Houe...