Evaluation of Mixed Hardwood Studs Manufactured By the Saw-Dry-Rip (SDR) Process

Abstract : In some areas, harvesting mixed hardwood species may be necessary to provide enough log volume to keep a hardwood stud mill in business. Basswood and red maple should make good studs and should be suitable for combination with yellow-poplar, paper birch, or other species shown to be good performers using the Saw-Dry-Rip (SDR) process. This study evaluates basswood, red maple, and black willow for making studs using SDR. Results show that basswood and red maple have lower crook when SDR is used with either conventional or high-temperature drying. Black willow crook is lower using SDR but is still much higher than basswood or maple. This poorer performance is believed to be due to wetwood and poor drying. Wrap in wetwood studs is due to wet pockets that are exposed when ripped from the flitches, causing delayed shrinkage after ripping. The percentage of pieces rejected because of warp, based on the STUD grade, is 50-100 percent lower for SDR than for conventionally sawed studs. Keywords include: Saw-Dry-Rip, SDR, hardwoods, studs, manufacturing, red maple, basswood, black willow, wetwood, sawing.