I have never seen this one I knew there had to be a 5mm shaft with what I want somewhere but now I have a drawing of it and am ready to make a 3d cad model so I now intend to see this through bUt definitely going to look into that pinion you recommended so I had another idea today while talking with a machinist and then we were saying why cant I make a socket headed cap screw to fit it, ie machine a gear and have it to have a counter sink for part of socket head cap screw to sit in I mean it's not a terrible idea at first glance but clearnence I for see being an issue and I definitely don't want the head hitting the spur gear