Commercial Evaluation of SDR (Saw-Dry-Rip)–Using Aspen for Door Parts

Manufacturers of aspen door parts (stiles and rails) use lumber from grade-sawn aspen logs, dried at temperatures less than 180?F. This practice results in a great deal of material that is excessively warped. The Saw-Dry-Rip (SDR) process for manufacturing studs has significantly reduced warp in aspen studs and should be suitable for use in manufacturing door parts. The SDR process is live-sawing flitches, drying them, and then ripping to final dimensions. A commercial trial to test SDR for door parts was conducted using aspen Conventional practices were compared to SDR in a door-part manufacturing plant in Michigan. The SDR process reduced crook and bow and, with high-temperature drying, reduced twist as well. While the trial showed significant reduction in warp, the total yield was better for grade-sawn lumber than for SDR live-sawn lumber. This result was due to the higher proportion of No. 1 Common and Better lumber in the grade-sawn material. If equal grades of lumber are used, we believe that the SDR process would result in higher quality and higher yield of parts.

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