RE: Where to buy scales?
You can get a pretty accurate fish scale at your local Bass Pro Shop. They sell a digital scale that works well for a good price. Just hang the plane from the scale and read the weight. For smaller parts, I use a postage scale (also digital) that I bought at one of the office joints (Office Max, Office Depot) and I weigh each part (especially the ribs) in order to keep the plane balanced laterally.
Bill, AMA 4720
WACO Brotherhood #1