Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): C. W. McMillin; G. E. Woodson
    Date: 1972
    Source: Forest Products Journal 22(11):55-59
    Publication Series: Miscellaneous Publication
    PDF: Download Publication  (1.1 MB)


    Holes 3-1/2 inches deep were bored with a 1-inch spur machine bit in southern pine having specific gravity of 0.53 (ovendry weight and volume at 10.4 percent moisture). The bit was rotated at 2,400 rpm and removed chips 0.020 inch thick. For wood moisture contents ranging from ovendry to saturation, thrust was lower when boring along the grain (average 98 pounds) than across the grain (average 138 pounds), while torque was higher when boring along the grain (average 42 inch-pounds) than across the grain (average 33 inch-pounds). For both boring directions, torque and thrust increased with increasing moisture content to a maximum at about 5 to 10 percent, then decreased to a constant value at about the fiber-saturation point. For the type of bit tested, net power at the spindle required to cut 0.020-inch-thick chips at speeds of 2,400 rpm or less should not exceed 2 hp., regardless of boring direction or moisture content; thrust should not exceed 200 pounds. Chip types resembled those obtained in orthogonal cutting.

    Publication Notes

    • You may send email to to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    McMillin, C. W.; Woodson, G. E. 1972. Moisture content of southern pine as related to thrust, torque, and chip formation in boring. Forest Products Journal 22(11):55-59

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page