Something that might be influencing the thread breaking is that the needle is not inserted correctly. It looks like it takes a round shank needle. There is a member of our Colorado Get-together group, that has worked with industrial machines that use round shank needles. She prefers them and mentioned that in an industrial setting that they work better so that the needle can be adjusted better to the hook on a variety of machines.
Janey - Neat people never make the exciting discoveries I do.