Thank you. Yes that Contec number is the right one. Trying to see if they sell to the United States.
I'm afraid the 7106501 is a different diameter or length since it is not for the H4. I haven't found measurement for sure. Another complication is the needles that came with this very well used machine are the smaller system 135 like the H3 not the 190 they say for the H4 so I'm wondering if it has been modified in some way.
I may have to find someone to tap it. I am not at all mechanical.