Possibly add a reverse lookup for the g codes and m codes? It would be nice to be able to look that up in case I forgot. Also the tap and drill chart could use a few more details, or possibly drop downs, filters, etc. What I'm trying to say the the tap and drill chart is just that, but this being an application it could be more interactive making it a more productive experience. Great start for version 1 though!
Machinist Toolbox at Google Play market analyse