This community building project was the fabrication and raising of a replacement timber frame for the sash mill at Sunrise Mills, a historic site belonging to Montgomery County in Pennsylvania. A sash mill saws timber using a vertically reciprocating saw blade mounted in a rectangular frame which resembles a window frame or sash, hence its name.The original sash mill dates back to the early 1770s and was built a few years after completion of the 1767 grist mill, a two-story timber frame; both are listed in the National Register of Historic Places. The sash mill was built to supply timber and lumber for the surrounding buildings, including a farmhouse and Swiss bank barn, and for the local community. Both mills were powered by water diverted from the Swamp Creek, which is a tributary of Perkiomen Creek. The historic documentation of the sash mill depicts a stout, three bent frame of timbers of various sizes (and presumably species) without the consistency we expect in building today. The limited documentation is not specific enough to allow a strict piece-for-piece replacement, so we will be following the original design as well as we can while creating a structure which is conducive to training volunteers in timber framing.
The Guild workshop fabricated and raised roughly 7,500 board feet of green oak timber. Square rule layout was used on rough sawn timber, and the frame was fabricated using hand tools and traditional timber framing methods. The oak flooring, white pine siding, standard lumber skip sheathing, and cedar shingles were also installed as part of the workshop. The stone-clad concrete raceway and sash mill foundations were already in place, so the workshop began with the fabrication and installation of timber sills and joists and the laying of the sash mill oak flooring. The flooring was laid roughly 12 feet above the water line, thereby creating a safe work platform for the frame raising. Several Montgomery County maintenance workers also assisted us during the workshop and were eager to learn timber framing skills which they can employ in the future on the County’s many historic structures. Because there were no reasonably-sized, level ground surface at Sunrise, we did the fabricating at Pennypacker Mills and trucked the timbers about five miles to Sunrise Mills. Pennypacker Mills, located on Perkiomen Creek, is a spacious park and historic site in its own right. It includes the historic Pennypacker Mills mansion furnished with the documented antique collection of the former Pennsylvania governor, Samuel W. Pennypacker.
TFG Sunrise Mill 2019