Thanks for the coments.
The crease is simple first I wet the sheath and then I have molded it with the front of my folding tool and then with Edding.
But the stitching is not perfect I still trying and learning. The twine is not so good I change it I think wax twine is better. and I must reshape the edges.
the measurments from the knife are:
Total length: 21,5cm
Blade:11,3cm
Grip: 10,2cm
Blade in the middle: 3,4cm
Other projects are a Bowie sheath and Holster for my SAA 7 1/2 but pics follow soon.