Characteristics of Torques for Driving Screws into Wood-Based Composites
Critical torque factors, typically used for screw-driving behavior, were used to investigate characteristics of torque behavior in wood-based composites. Factors investigated were wood-based composite type, embedded screw orientation, and pilot-hole diameter. Recorded torque-time curves, which illustrated the complete process of driving screws into wood-based composites, indicated that screw torques behaved differently in sides and faces of wood-based composites and that the whole screw-driving process can be divided into two phases. Critical torques of these two phases on torque-time curves were defined and named. Statistical analyses of evaluated factors on critical torques, such as maximum drive torques (MDT) and stripping torques (STT), indicated that those factors had significant interactive effects on critical torques. Oriented strandboard materials evaluated had mean MDT from 1.04 to 1.75 Nm, mean STT from 3.30 to 5.91 Nm, and mean STT-to-MDT ratios from 3.18 to 3.53. Particleboard materials had mean MDT ranging from 1.01 to 1.84 Nm, mean STT ranging from 3.12 to 6.05 Nm, and mean STT-to-MDT ratios ranging from 3.08 to 3.29.
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.