mario: it's been a long time since we have heard from you. thanks for sharing your video. a very good one, i might add. i loved the little violin you showed. your video showed a valuable lesson on soldering. one can see the very slow application of heat. many apply too much, too fast. thus going to a disaster. thanks again, mario.Below you'll find a video I did a few years ago - move to minute 2:50 - you will see, how to start the cut with a bench jeweler saw. The blade I use there is about 0.25 mm witdh. Start slowly, don't hurry and feel the tool and what it needs and use the hole length of the blade - practice a lot and you'll be faster and faster.
[video]https://youtu.be/wf6IFKSFefk[/video]