Sawing and Drying

You are not logged in. [ Login ] Why log in
(NOTE: Login is not required to post)

River Birch mill thickness prior to kiln dry

2/9/16       
BR

Want to make a dining room table. No experience milling/kiln dry. Have River Birch in front yard and want to make table. Need opinion on how thick to mill lumber prior to kiln dry so table can be
1 1/8" - 1 1/2" once finished.
Thank you

2/11/16       #3: River Birch mill thickness prior to ...
Gene Wengert-WoodDoc

Shrinkage in drying to 6% MC is about 7.4% on the average. A few pieces will shrink as much as 8% or 0.12". So, the green size needs to be 1.62" so that the final size is 1.5", but most pieces will be thicker. Then you also need to add a planer allowance of no less than 0.06", and a bit more of the lumber is rougher than normal. Than add a little more for cupping warp. River birch does indeed cup more than many species, so 0.12" is none too much. Then because the mill will cut plus or minus a little bit, you need to add 0.05" or more. So, to achieve all pieces at 1.50" after drying and planing, the green average size, also called target size, needs to be 1.50+0.12+0.06+0.12+0.05 = 1.85"

Now, many mills will cut a little thinner, because this assumes that you want every piece thick enough (1.50" after kiln drying and planing), and it is expensive to be perfect. So, maybe 1.80” target is more reasonable. Note that if you were to buy kiln dried lumber, the assumption or industry practice is to have 1.50" or thicker prior to drying for 6/4. This means that at the mill you can forget about shrinkage, planer allowance, and cupping, so you only need a target of 1.55" or 1/16" over thickness. However, tradition says 3/32" (0.09") or even 1/8” (0.12) over thickness, but this was developed when sawmills used circle saws which needed more planing to be smooth and target setting was not accurately indicated on the mill (more plus and minus thicknesses). Today, surfaces are smoother because saws are better and oftentimes the setting on the mill is very accurate so lumber thickness varies only a small amount.

2/11/16       #4: River Birch mill thickness prior to ...
BR

Perfect, very helpful.

Thank you

Guy cutting tree down says he has a mill and can do job. Any pertinent questions I should ask?

2/12/16       #5: River Birch mill thickness prior to ...
Steve

Just some thoughts. I'm not familiar with River Birch at all.
If your table is going to be one piece you might want to consider it being at least 2" thick if not 2 1/2" thick. Thicker is more likely to resist cupping after assembly. Thicker is also more rustic!

Even in a glue up (two or more boards) thicker is more stable.

Ask the sawyer what his cutting tolerance is and add that to what ever thickness your request.

Be very particular with leveling the boards/slabs while they are drying. 1/4" out of level is 1/4" of wood that needs to be planed off to get a flat board/slab to make into a table.

And be sure to put some kind of finish on the bottom of the table so you don't have different seasonal moisture changes from top to bottom which will cause warpage

2/12/16       #6: River Birch mill thickness prior to ...
rich c.

If stock wants to cup, thickness is not going to limit that. If you like Viking looking furniture you can go that thick, but I sure wouldn't want to move it into the house! Some to this heavy slab furniture being built has to take 6 people to move it through a doorway.


Post a Response
  • Notify me of responses to this thread
  • Subscribe to email updates on this Forum
  • To receive email notification of additions to this forum thread,
    enter your name and email address, and then click the
    "Keep Me Posted" button below.

    Please Note: If you have posted a message or response,
    do not submit this request ... you are already signed up
    to receive notification!

    Your Name:
    E-Mail Address:
    Enter the correct numbers into the field below:
     

    Date of your Birth:



    Return to top of page

    Buy & Sell Exchanges | Forums | Galleries | Site Map

    FORUM GUIDELINES: Please review the guidelines below before posting at WOODWEB's Interactive Message Boards (return to top)

  • WOODWEB is a professional industrial woodworking site. Hobbyist and homeowner woodworking questions are inappropriate.
  • Messages should be kept reasonably short and on topic, relating to the focus of the forum. Responses should relate to the original question.
  • A valid email return address must be included with each message.
  • Advertising is inappropriate. The only exceptions are the Classified Ads Exchange, Machinery Exchange, Lumber Exchange, and Job Opportunities and Services Exchange. When posting listings in these areas, review the posting instructions carefully.
  • Subject lines may be edited for length and clarity.
  • "Cross posting" is not permitted. Choose the best forum for your question, and post your question at one forum only.
  • Messages requesting private responses will be removed - Forums are designed to provide information and assistance for all of our visitors. Private response requests are appropriate at WOODWEB's Exchanges and Job Opportunities and Services.
  • Messages that accuse businesses or individuals of alleged negative actions or behavior are inappropriate since WOODWEB is unable to verify or substantiate the claims.
  • Posts with the intent of soliciting answers to surveys are not appropriate. Contact WOODWEB for more information on initiating a survey.
  • Excessive forum participation by an individual upsets the balance of a healthy forum atmosphere. Individuals who excessively post responses containing marginal content will be considered repeat forum abusers.
  • Responses that initiate or support inappropriate and off-topic discussion of general politics detract from the professional woodworking focus of WOODWEB, and will be removed.
  • Participants are encouraged to use their real name when posting. Intentionally using another persons name is prohibited, and posts of this nature will be removed at WOODWEB's discretion.
  • Comments, questions, or criticisms regarding Forum policies should be directed to WOODWEB's Systems Administrator
    (return to top).

    Carefully review your message before clicking on the "Send Message" button - you will not be able to revise the message once it has been sent.

    You will be notified of responses to the message(s) you posted via email. Be sure to enter your email address correctly.

    WOODWEB's forums are a highly regarded resource for professional woodworkers. Messages and responses that are crafted in a professional and civil manner strengthen this resource. Messages that do not reflect a professional tone reduce the value of our forums.

    Messages are inappropriate when their content: is deemed libelous in nature or is based on rumor, fails to meet basic standards of decorum, contains blatant advertising or inappropriate emphasis on self promotion (return to top).

    Libel:   Posts which defame an individual or organization, or employ a tone which can be viewed as malicious in nature. Words, pictures, or cartoons which expose a person or organization to public hatred, shame, disgrace, or ridicule, or induce an ill opinion of a person or organization, are libelous.

    Improper Decorum:   Posts which are profane, inciting, disrespectful or uncivil in tone, or maliciously worded. This also includes the venting of unsubstantiated opinions. Such messages do little to illuminate a given topic, and often have the opposite effect. Constructive criticism is acceptable (return to top).

    Advertising:   The purpose of WOODWEB Forums is to provide answers, not an advertising venue. Companies participating in a Forum discussion should provide specific answers to posted questions. WOODWEB suggests that businesses include an appropriately crafted signature in order to identify their company. A well meaning post that seems to be on-topic but contains a product reference may do your business more harm than good in the Forum environment. Forum users may perceive your references to specific products as unsolicited advertising (spam) and consciously avoid your web site or services. A well-crafted signature is an appropriate way to advertise your services that will not offend potential customers. Signatures should be limited to 4-6 lines, and may contain information that identifies the type of business you're in, your URL and email address (return to top).

    Repeated Forum Abuse: Forum participants who repeatedly fail to follow WOODWEB's Forum Guidelines may encounter difficulty when attempting to post messages.

    There are often situations when the original message asks for opinions: "What is the best widget for my type of shop?". To a certain extent, the person posting the message is responsible for including specific questions within the message. An open ended question (like the one above) invites responses that may read as sales pitches. WOODWEB suggests that companies responding to such a question provide detailed and substantive replies rather than responses that read as a one-sided product promotion. It has been WOODWEB's experience that substantive responses are held in higher regard by our readers (return to top).

    The staff of WOODWEB assume no responsibility for the accuracy, content, or outcome of any posting transmitted at WOODWEB's Message Boards. Participants should undertake the use of machinery, materials and methods discussed at WOODWEB's Message Boards after considerate evaluation, and at their own risk. WOODWEB reserves the right to delete any messages it deems inappropriate. (return to top)


  • Forum Posting Help
    Your Name The name you enter in this field will be the name that appears with your post or response (return to form).
    Your Website Personal or business website links must point to the author's website. Inappropriate links will be removed without notice, and at WOODWEB's sole discretion. WOODWEB reserves the right to delete any messages with links it deems inappropriate. (return to form)
    E-Mail Address Your e-mail address will not be publicly viewable. Forum participants will be able to contact you using a contact link (included with your post) that is substituted for your actual address. You must include a valid email address in this field. (return to form)
    Subject Subject may be edited for length and clarity. Subject lines should provide an indication of the content of your post. (return to form)
    Thread Related Link and Image Guidelines Thread Related Links posted at WOODWEB's Forums and Exchanges should point to locations that provide supporting information for the topic being discussed in the current message thread. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related Link that directs visitors to an area with inappropriate content will be removed. WOODWEB reserves the right to delete any messages with links or images it deems inappropriate. (return to form)
    Thread Related File Uploads Thread Related Files posted at WOODWEB's Forums and Exchanges should provide supporting information for the topic being discussed in the current message thread. Video Files: acceptable video formats are: .MOV .AVI .WMV .MPEG .MPG .MP4 (Image Upload Tips)   If you encounter any difficulty when uploading video files, E-mail WOODWEB for assistance. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related File that contains inappropriate content will be removed, and uploaded files that are not directly related to the message thread will be removed. WOODWEB reserves the right to delete any messages with links, files, or images it deems inappropriate. (return to form)