Shrinkage allowances for red oak
Estimating radial and tangential shrinkage when drying red oak to 12 to 14 percent MC. 1998.
by Professor Gene Wengert
I am going to slice 6/4 green northern red-oak (quercus rubra) to make flooring wear layers for a Swedish laminated flooring company to a thickness of .189" x 8-3/4" in width, and then dry these wear layers to 12-14% or so.
My question is, with a rather gentle forced-air kiln at a temperature of approx 95 degrees F, how much shrinkage should I allow for radially and tangentialy as well?
Also, as we are in Idaho, we use a lot of white spruce stickers. This should hopefully not stain the wood. Would spruce be the desired sticker-material?
The standard shrinkage values for northern red oak from green to 12% are averages (so half the pieces will shrink slightly more) and also vary for each species of red oak. To be 100% safe, I would expect 9% tangential and 4.5% radial. This means that all pieces will actually be too wide, so you may wish to save a little wood and make them 4% and 7.5% larger, which means that once in a while you will have a narrow piece, but not very often.
No problem with the spruce sticks if they are dry.
Professor Gene Wengert is Extension Specialist in Wood Processing at the Department of Forestry, University of Wisconsin-Madison.
Click on Wood Doctor Archives to peruse past answers.
If you would like to obtain a copy of "The Wood Doctor's Rx", visit the Wood Education and Resource Center Web site for more information.
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: Architectural Millwork: Flooring
KnowledgeBase: Laminates & Solid Surfacing: Materials
KnowledgeBase: Primary Processing: Kiln Operation
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 © 1996-2016 - WOODWEB ® Inc.