Causes for warpage after planing
Why boards may warp after surfacing. January 16, 2001
Iíve had some warping after jointing a board dead flat and running it through the planer. This has occurred with oak, maple and pine. Any thoughts?
You may not be letting the lumber acclimate to your shop long enough--at least a week, two if possible. Also, try planing off opposite faces more equally.
Maybe the wood wasnít dried thoroughly. Cut a wood block 1.5" x 1.5" and weight it on a scale. Dry it for 24 hours. Weigh it again. Then use the equation MC= (MassWet-MassDry)/MassDry * 100. This will give you the moisture content.
The cause is drying stress (casehardening), which should be relieved in the kiln by a process called conditioning. Sometimes the process is not done correctly or at all.
You can check for stress by cutting a clothespin-shaped sample from the lumber--many texts illustrate how to do this. Wood with drying stress should be returned to the seller.
If it were a moisture problem, then you would see warp developing after jointing and before planing.
Gene Wengert, forum technical advisor
Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?
Have you reviewed the related Knowledge Base areas below?
KnowledgeBase: Lumber & Plywood: Storage
KnowledgeBase: Primary Processing: General
KnowledgeBase: Primary Processing: Kiln Operation
KnowledgeBase: Solid Wood Machining
KnowledgeBase: Solid Wood Machining: General
KnowledgeBase: Wood Engineering: Wood Properties
KnowledgeBase: Woodworking Miscellaneous
KnowledgeBase: Woodworking Miscellaneous: Woodworking
KnowledgeBase: Knowledge Base
All rights reserved. No part of this publication may be reproduced in
any manner without permission of the Editor.
Review WOODWEB's Copyright Policy.
The editors, writers, and staff at WOODWEB try to promote safe practices.
What is safe for one woodworker under certain conditions may not be safe
for others in different circumstances. Readers should undertake the use
of materials and methods discussed at WOODWEB after considerate evaluation,
and at their own risk.
335 Bedell Road
Montrose, PA 18801
Copyright © 1996-2013 - WOODWEB ® Inc.