I Have A Pfaff 463 Industrial Sewing Machine. How Do I Get It To Work How It Used To? It's Bunching Under The Fabric.

I have this sewing machine as well (that I just purchased in the summer at a thrift store).  I was having the same problem until I re-read the book and realized that it's all related to the tension dial.  This machine is kind of 'double' threaded around the dial and this will make or break it for you when sewing.  Check this - 'double' check it and you should be fine.  The other tip is that you must pull the thread correctly through the bobbin casing.  Look at it close up and you'll see a area that you put the thread through before you pull it up with the needle.  Good luck!

Check the top is threaded correctly.  Check you have correctly put in the bobbin from below and picked up the first stitch.  Tighten your tension screw until it is the correct tension.  Use some scrap material to test.