Pinion Jigs and fly cutting

I think I said it earlier that model engineering and in particular clock making is the art of making tools to make tools that make parts. Although there has not been much shop time lately I did take some time at the end of the summer (2010) to build a pinion milling jig. The plans for this came from Model Engineer's Workshop #164. Not having large mild steel on hand I made it from aluminum.

The lesson here came from proper grinding of a fly cutting bit. Have a look at this great site for details on grinding a fly cutter bit. http://start-model-engineering.co.uk/begin-with-bogs/fly-cutting/
This site is an excellent resource and a good list of model engine projects.