While trying to serve a bow string, I've always been frustrated by my inability to catch the bobbin at just the right place to give it another spin. Finally it annoyed me enough to cobble together a gizmo that I believe solves my problem. This jig fits around my Bieter (best jig IMHO) and with the counter weights adjusted allows me to spin the bobbin and no matter where it stops I'm in position to give it another spin.
Obviously none of us on the DIY are prone to leaving well enough alone so of course now that I have the spinning part resolved I want to use my hand drill to make it a powered serving tool. You'll note that I have put a V cut in the exterior of the circle so that it can be belt driven. Unfortunately my sewing machine belt I ordered from Ebay has not yet arrived so I cannot say definitively that it will work. Honestly I'm pretty sure it will.
Now if you are thinking this is just a little too much work, there is a commercial alternative on the market and can be purchased from Ebay or viewed here