I have dusted off the Stuart 10V castings, dug out the building book and found Issue 51 of MEW. Time to get started after only four years.
In MEW 51, there is an article about jigs and fixtures by Harold Hall. He uses the 10V as an example. In it he suggests machining the flywheel and bearings on a taper mandrel once the bores have been reamed. This, he says, allows for good accuracy and will permit both sides of the flywheel to be machined by simply removing it from the taper mandrel and turning it over.
I can't see how this works. I don't doubt that it does, I just don't understand and can't find any reference in my meagre library to the technique. It seem to me that any taper will, by definition, leave the flywheel tight at one end and loose at the other. I even did some sums. Over the 3/4" of the flywheel length, if I had a taper of 0.5 deg (1 degree included), the casting would have one end tight and the other
0.013" oversize. That would wobble about all day and any machining forces would throw it out of true.What have I missed? Can someone explain (or point me to an explanation) of the business of turning accuately on a taper mandrel?
Thanks
Pete Harrison