Rebuiding is the process of returning the piano to original playing condition.  This would include

• New pinblock, tuning pins and strings
• Repair or replacement of soundboard
• Bridge repair or replacement
• Action replacement or restoration
• New hammers
• New damper felts 
• Rebuilding of trapwork (pedals).
• Keytop replacement or ivory repair
• Key bushing

Refinishing refers to the outside case parts.  Piano refinishing is more complex than normal refinishing.  The finish serves to protect the instrument from moisture and keep it more stable.  Piano finishes usually have more coats, filling the pores of the wood completely, and are hand rubbed for a more professional looking sheen.

The piano to the right is a completely rebuilt and refinished Steinway O manufactured in 1905. 

A rebuilt piano should sound and feel as good or better than it did when it originally left the factory.  Good rebuilding carefully analyzes the needs of each individual instrument so that orginal parts  capable of being restored are utilized, producing an instrument that is as faithful to the original as possible.