SAWMILLING PRACTICES FOR HARDWOODS
John “Rusty” Dramm1
Abstract.—The Sawmill Improvement Program (SIP) provides guidance to improve
the bottom line of a sawmill both by recovering more lumber from a log and by using
simplified procedures to produce more grade lumber. Lessons learned from SIP have
led to improved yields of grade lumber through improved log manufacturing, reducing
sawing variation by using thinner kerf saws and better decisionmaking from debarking
of logs to edging of grade lumber, and better product sizing by reducing dimensional
oversizing and excessive planning allowances. Developing higher grades of lumber
requires a skillful edger and trim saw operator as well as a skillful sawyer.
State and Private Forestry of the U.S. Forest Service
began the Sawmill Improvement Program (SIP) in
the 1970s to extend the Nation’s timber resources by
identifying practices both to increase lumber recovery
and to mill hardwood logs more efficiently. Lessons
learned from SIP have led to improved yields of
grade lumber through improved log manufacturing,
reducing sawing variation by using thinner kerf saws
and better decisionmaking from debarking of logs
to edging of grade lumber, and better product sizing
by reducing dimensional oversizing and excessive
planning allowances. Lumber lost was estimated to be
15 percent from oversizing, 12 percent from excessive
sawing variation, 20 percent from heavy slabbing, 20
percent from overedging, and 6 percent from excessive
saw kerf. Losses in log volume were estimated to be as
high as 10 to 15 percent from poor debarking and 2 to
8 percent from poor processing decisionmaking.
Figures 1, 2, and 3 illustrate a portion of the simplified
procedure for developing grade lumber from hardwood
logs (Malcolm 2000). A working knowledge of the
hardwood grade rules of the National Hardwood
National Sawmill Specialist (JD), U.S. Forest Service,
Forest Products Laboratory, One Gifford Pinchot Dr.,
Madison, WI 53705-2398. To contact author, call
608-231-9326 or email [email protected].
1
Proceedings of the Seventh Walnut Council Research Symposium
Lumber Association is essential for processing grade
lumber (American Hardwood Export Council 2002).
Of first importance in sawing for grade is recognizing
external indicators of internal defects. The position of
the other three sawing faces is fixed as soon as the first
face is sawn. Defects should be located at the edges or
corner of sawn lumber where they can be edged off.
The poorest face should be sawn first to provide a firm
bearing from which to saw the better faces for grade.
Walnut should be opened to a 5.5-inch face and other
hardwoods should be opened to a 6.5-inch face. Wide
boards should be ripped into two boards when more
than half the original surface can be raised one grade
and the remaining board does not drop more than one
grade.
LITERATURE CITED
American Hardwood Export Council. 2002. The
illustrated guide to American hardwood lumber
grades. Washington, DC: American Hardwood
Export Council. 24 p. Available at http://www.ahec.
org/hardwoods/pdfs/IllustratedGradingGuide.pdf.
Malcolm, F.B. 2000. A simplified procedure for
developing grade lumber from hardwood
logs. Res. Note FPL-RN-098. Madison, WI: U.S.
Department of Agriculture, Forest Service, Forest
Products Laboratory. 13 p. Available at http://www.
fpl.fs.fed.us/documnts/fplrn/fplrn98.pdf.
GTR-NRS-P-115
11
1.
4.
2.
5.
3.
6.
Figure 1.—Series of slides listing the findings of the Sawmill Improvement Program and illustrating the importance of
identifying defects before opening a log to produce grade lumber (illustrations from Malcolm 2000).
Proceedings of the Seventh Walnut Council Research Symposium
GTR-NRS-P-115
12
1.
4.
2.
5.
3.
6.
Figure 2.—Series of slides illustrating how to open a log and when to rotate to maximize production of grade lumber
(illustrations from Malcolm 2000).
Proceedings of the Seventh Walnut Council Research Symposium
GTR-NRS-P-115
13
1.
4.
2.
5.
3.
6.
Figure 3.—Series of slides illustrating how to open logs with sweep, seams, and rot, and how to edge and rip for production of
grade lumber (illustrations from Malcolm 2000).
The content of this paper reflects the views of the author(s), who are
responsible for the facts and accuracy of the information presented herein.
Proceedings of the Seventh Walnut Council Research Symposium
GTR-NRS-P-115
14