As in many other fields, data is a very important matter. We have to find our spare parts, adjust the timegrapher to the correct lift angle, etc., so it’s very important to have the right data at hand.
So far, Generale Ressorts published a printed catalogue a very long time ago, and that’s still the only source of data when it comes to matching mainsprings with movements. There are some suppliers that have entered some of this data (Cousins, Ofrei, Boley) into their own systems, but a generally available list of mainsprings and where they fit wasn’t available anywhere.
As I’m a bit of a computer geek myself, I thought it was time to change that.
My first data project was to find a list of all winding stems and balance staffs, and to digitise that. The result is a searchable database for balance staffs and winding stems, also listing suppliers, and letting you search buy size. It’s at https://watchparts.org.uk/cgi-bin/watchparts.
My next project was a list of lift angles, which I compiled from various sources, which can be found at https://watchguy.co.uk/cgi-bin/lift_angles.
Last but not least, I attacked the mainsprings. GR gave me a PDF with all their products (8,800), and I put those into a database. Then came the larger problem of scanning and extracting the data from the printed catalogue, which gave me 14,624 different calibres and their mainspring, which I also loaded into the database.
The result is at https://watchguy.co.uk/cgi-bin/mainsprings, and this should be the ultimate mainspring list that is freely available.
If anyone wants the raw data for their own project, please let me know and I will let you have it if you publish the source.