Before you decide whether you want to rebuild an older piano or not, read one of the best books available on the subject.

"Piano Servicing & Restoration" by Arthur A. Reblitz

Here's one link for downloading: http://www.4shared.com/document/ApLS...iano_servi.htm

Another thing to consider, there are reasonably easy repairs for just about anything on a piano. A cracked pin block is quite serious, but even that can be repaired by various methods or even replaced. The reason these pianos are being disposed of is because of the labor rate difference between US and China. That is unfortunate, in a way, because many fine older instruments are being cast off that have the potential for being very solid performers for many years to come given proper attention.

If this is something you really want to do, I'll bet you can find a fine old Bush & Lane, Ludwig or other brand with a reasonably tight pin block and no major structural issues in your area for a few hundred dollars or less. You might be able to trade work with a piano technician -- say refinish the case on an old aligatored grand or two in exchange for rescaling, restringing and a set of new hammers for your Knabe upright. Who knows?

If you're going in hoping to make it a profitable venture financially, forget about it. But a lot of us old retired guys do a lot of crazy things just for our own amusement and edification. :>)