Data needed before opening hammer package: (1) String height at end of each section plus mid note at tenor section since this section is very long. The tenor section on this Mason is from note 21 to note 51. String height at note 35 is also recorded. (2) String angle along hammer strike line. Hammers will be drilled at an angle so the hammer top surface is parallel to the strings. (3) Hammer flange center pin height. Hammer bore = String height - Flange center pin height

Glue on felt on bottom of guide rails with felt glue. We used Roo Glue here. Trim felt and cut open screw holes. Without cutting the screw holes open, the felt will twist, move or loose it's position when driving screws in later. 

This post tributes to my dearest mentor Mr. David Betts.

Trible check that the plate is fully mounted in piano with webbing screws and perimeter bolts, nose bolts and cap tightened together, agraffes aligned, and duplex bar (not shown here yet) prepared. Jack up pinblock with supporting jig.