Where can I find the differential formula for my hobbing machine?
Here are some obvious (and not so obvious) sources for your machine’s differential formula: (1) OEM User’s Manual When a machine leaves the manufacturer, it is accompanied by the user’s manual. This is the best source for information (So why is it that, when a machine gets sold, it and the manual are soon parted?). Contact the manufacturer for a copy of their manual if you can still find them. The manufacturer will need at least the model and serial numbers. A quick call or email to the manufacturer requesting serial number location usually works. (2) After Market User’s Manual Go to the top of this FAQ for some sources for manuals. An After Market manual is usually obtained from a machine tool dealer, community of users, or a helpful shop that has the same machine and is willing to share. One thing to watch out for: models of the same machine are often produced with different constants. This is especially true of the index constant, Machines of the same model are rarely produced with
