Home » Knowledge Base » Knowledge Base Article What's New  |  Site Map 

 

 
   
   
 
 


Today's
Sponsors:


Woodcraft Supply Corp.

WoodcraftPlans.com

WoodenBoat

WoodFinder

WoodJobs.com Search Consultants

Woodland Dimension Products

WoodLINKS

Woodmaster

WoodPlanet Inc.

WOODWEB

Woodworker's Supply/woodworker.com

Woodworker's Directory

Wright Timber

SK-USA

SketchList

SlipCon USA, Inc.

SoCalMachinery.com

South State Machinery

South Texas Moulding

Southeast Tool, Inc.

Specialtytools.com

SprayGunWorld.com

Stairguy Stairbuilding Videos

Stefani

Steve H. Wall Lumber Co.

Stiles Machinery

Stiles Shop Solutions

Stor-N-Fold Systems

Super Source Tooling Inc.

Supergrit Abrasives

Surface and Panel Magazine

Target Coatings

Techno CNC Routers

Template Services

Teragren

The Cayce Company

The Veneer Store

Thermwood Corporation

TigerStop

TigerwoodDecking.com

TimberKing

Timesavers Inc.

TMS Machinery Sales

Tongass Forest Enterprises

Tooling on the Web

Toolstoday.com

Touch Up Solutions LLC

Tractivity

TradeSoft

Trakware Systems Inc.

TRB Flooring Company

Tropical American Tree Farm

Tropical Hardwoods

UC Coatings Corp.

Unique Machine & Tool

University of Wisconsin

UWMO Auctions

VacDry Kilns

Vacuum Pressing Systems, Inc.

Vacuumpods.com

Vecoplan LLC

Vector Art 3D

Vectric Ltd.

Veneer Systems Inc.

Veneer Technologies Inc.

Vintage Perkins

VortexTool Co. Inc.

VyTek

W. Moore Profiles, Ltd.

W.L. Fuller

Wadkin North America

Wagner Electronic Products

WalzCraft Industries

Webb Abrasives

WEIMA America, Inc.

Weinig Group - USA

Western Dovetail

Williams and Hussey

Wisconsin Knife Works

WMIA

WMMA

Wood and Wood Products

Wood Doctor's Rx, LLC

Wood Tech Enterprises, Inc.

Wood Technology Inc

Wood-Mizer

Wood-Ply Lumber Corp.

WoodCabinetDoors.Com



WOODWEB DISCLAIMS any and all RESPONSIBILITY and LIABILITY for the accuracy and application of the information below. Readers agree to evaluate the significance and limitations of the information provided, and accept full responsibility for the application of this information. Read More ...

Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?



Solid Wood Octagon Table Top Failure       Wood movement dooms a solid wood "sunburst" table top, and we learn why that will always happen. February 12, 2007

Question
I am building an octagon end table for a customer and have it totally built and ready to go. There was about a week of time where I had moved the table from my shop (unheated insulated building) to a basement. The top is 8 pie-shaped pieces glued together with biscuits. The base is enclosed with frame and panels. Well, the project kind of stalled and everything was fine while sitting in my shop... Then I moved it to the basement away from the dust where it sat again for a week or so until I could finish it. When I went back, the top was like a shallow bowl. I don't know what to do. I need to get it flat again. What can I do to prevent this in the future? The whole problem (I think) is that it's an octagon and I wasn't sure what wood movement was going to do. It's made of solid maple. And I don't want to start from scratch or cut it up again if at all possible.

Forum Responses
(Furniture Making Forum)
From contributor T:
Which way does the grain run? Is the maple 1/4 sawn or flat sawn? How thick is the top? How is the top fastened to the base? What was the moisture content of the maple? Many things to consider when building a piece like this.



From contributor W:
Are you saying that the top is basically a sunburst, but made out of solid wood? If so, and the grain runs radially (from the center out toward the edges), I would expect each pie wedge to expand and contract across its width, with more expansion/contraction happening out toward the edges of the table where the wedges are wider. If the top is built as described above, I'm not sure you can avoid this bowl shape phenomenon. This is why sunbursts are typically done using veneer on a stable substrate. I've never heard of anyone doing a sunburst in solid wood, but I could just be ignorant, too. Do you have the capability to do a veneered top? I know it sucks to do it over, but... If it's not basically a sunburst out of solid wood, please describe it for us.


From the original questioner:
You nailed it... The grain runs radially, it's a 3/4 inch thick top, flat sawn. Right now it is fastened to the top via Z shaped clips. Unfortunately, I don't know the moisture content and I also don't have the equipment to do a veneer top. I knew I was going to be in trouble when I started this top but had to try.


From contributor J:
About 6 years back, the widow of a friend of mine gave me the pieces of a solid cherry 60" octagonal dining table that he designed the same as yours. Half of the 1" thick top was glued together already, so I figured I could glue the rest together and use it at our place. She had suggested we sell it, but I could tell by the design that it would self-destruct. Sure enough, the first time a Santa Ana wind came through, the moisture dropped and there was a 1/2" opening ripped in the top. When the humidity goes up, it closes. Sorry, but the only way you are going to accomplish this design is by using veneer on a stable substrate. The bowl shape is bad enough, but just wait until the solid wood decides to tear itself apart. It's good that you discovered this problem in your shop and not at your client's place.


From contributor B:
Interesting! Would it work if the grain was to run side to side? It probably wouldn't technically be a sunburst pattern, but would it be stable? I'm talking about using solid wood again.


From contributor P:
It won't work if made of solid in 8 pieces no matter what direction the grain runs. It would be easy to make it out of solid with all the boards edge glued parallel and simply cut to an octagonal shape, although not as interesting looking. This would work as long as you accommodated movement across the grain when you fastened it to the base.


From the original questioner:
I would like to thank you all for your responses. I have decided to rebuild the top with straight boards. I see the problem now. I love the look but couldn't see the physics part of it. Veneer next time, once I learn how. Thanks to all of you. I love WOODWEB.
Have you reviewed the related Knowledge Base areas below?
  • KnowledgeBase: Knowledge Base

  • KnowledgeBase: Furniture

  • KnowledgeBase: Furniture: General

  • KnowledgeBase: Wood Engineering

  • KnowledgeBase: Wood Engineering: Wood Properties




    Would you like to add information to this article? ... Click Here

    If you have a question regarding a Knowledge Base article, your best chance at uncovering an answer is to search the entire Knowledge Base for related articles or to post your question at the appropriate WOODWEB Forum. Before posting your message, be sure to
    review our Forum Guidelines.

    Questions entered in the Knowledge Base Article comment form will not generate responses! A list of WOODWEB Forums can be found at WOODWEB's Site Map.

    When you post your question at the Forum, be sure to include references to the Knowledge Base article that inspired your question. The more information you provide with your question, the better your chances are of receiving responses.

    Return to beginning of article.



    Refer a Friend || Read This Important Information || Site Map || Privacy Policy

    Letters, questions or comments? E-Mail us and let us know what you think. Be sure to review our Frequently Asked Questions page.

    Contact us to discuss advertising or to report problems with this site.

    To report a problem, send an e-mail to our Webmaster

    Copyright © 1996-2008 - WOODWEB ® Inc.
    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.

    WOODWEB, Inc.
    RR4 Box 265A
    Montrose, PA 18801

    Contact WOODWEB