Sonora Nocturne screw

[moetzmoet]

I ordered medium tone and when I tighten down the screw it just falls out. Would anyone know which are the best for my machine and where to buy?

[Inigo]

But have you examined the needle chuck? It's it that the needle is too thin, or that your needle screw is too short to reach the needle and press it against the opposite side? If this is the case, you should replace the screw