in the start of 1900 a murdered man from about 1300 century was found in the south/west of Sweden. In his belt he has a knife there also the handle have a protection of leather, a "hat". To take out the knife from the sheath, he must first remove the hat from the handle, then take out the knife. This is what we in Sweden call a hattkniv = hatknife.
The picture is not the best but I think you can se the construction of the leather work. This hatknife I make for many years ago and it is of my own design. I use a piece of wood in the top of the hat.
During these days I think the knife have very high value. To secure the knife, and protect the knife from water, they made this design. A sort of cigar case but for a knife.
Anther way to make the knife secured in the sheath.
If you study the knife you see that on the handle I have made a U-shape, about 2 mm deep, going around the handle. When I make the sheath, the leather is wet. I press in the leather in the U-shape and let dry. This method allowed you to use just 10 mm of leather around the handle. The U-shape make the knife very well secured in the sheath.
I have used this method for many years on my knifes and it works very well. You also get the Scandinavian click when you put the knife in the sheath.
For a hatknife, this method is very nice. If you try it on a regular knife, you must make a heavy sheath and a light handle on the knife f to get the balance right when you carry the knife in your belt.
Regards
Thomas