Post a Response Subscribe Guidelines

Furniture Making

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

Inspecting lumber that will not cut straight

10/12/22

Mike

I have been in this business for 28 years and have spent the past 22 being self employed�..

Even with that, I pose this interesting question �

Is there a way to look at a board and be able to tell it is not going to end up leaving a straight cut on the off cut?

Let me clarify� After I have a straight edge on a board after i run it through my jointer, can someone explain why after the first cut, especially when a piece becomes narrower, it doesn�t stay straight and I have to run it through my jointer again, unless it�s too small in width to run it through.

This happens even one for are say 5 inches wide.

I buy my boards from well known suppliers and often times, need to buy it from places open to the public, so I can pick my boards, so�..

Is there a way to tell from just looking at a board if im going or not need to rejoint the off cut, unless I want to?

In case you�re wondering, I use a Powermatic 66 and a PM 6� long bed jointer

Note- i use my aluminum straight edge to verify the jointer has made a �perfect� straight edge, before i run it through my table saw

10/12/22 #2: Inspecting lumber that will not cut ...

Thomas Gardiner

Short answer is yes and no. There are some clues you can look for to tell you when a board will have internal stresses that will bow the cut. Differential ring spacing on one side to the other when looking at the end grain (compression wood from a leaning tree), evidence of a large knot nearby one side, how bowed the rough board was before jointing are some I can think of.
However most boards will bow somewhat after ripping because wood has stresses that are relieved when cutting. A better practice is to break out rough boards first then joint and plane to dimension. I only joint first if the board is way to bowed to run safely through the saw. Most of the time I use the sliding table to square up and then rip oversized

10/12/22 #3: Inspecting lumber that will not cut ...

RichC

Do you let your stock acclimate a little after bringing it into the shop? Do your suppliers store the stock in climate controlled conditions? Do you check moisture levels on every board? Not every board out of a kiln charge will be equal.

10/14/22 #4: Inspecting lumber that will not cut ...

Dave Sochar

Member

You are getting slightly stressed lumber. So are the retail shops you buy from.
No, you cannot reliably tell when a board is stressed just by looking at it.
If you have a 5" wide rough board with a 3/4" bow in length on each edge, you can joint that 3/4" out with a few fast passes at 1/8" to 1/4" and have a straight edge. Unbeknownst to you, each time you take off 1/4" or whatever off of an edge, the board (the internal stress) will move just a little as the board adjusts to its new stresses. Do it again, and it moves again.
Decide to live with it, and rip to width, and as the tension that is in that edging comes away, the whole tension structure of the board changes - and you lose your straight edge. Or maybe, you get it back - an example of one form of tension balancing another tensioned edge.

No matter - you need a new vendor. Make up a few casehardening test samples (see attached) from his/her lumber so they can understand what you are talking about. You would be surprised how many lumber sales people have no idea what all theses terms mean.

Purdue Comes to Aid of Woodworkers

10/14/22 #5: Inspecting lumber that will not cut ...

Dave Sochar

Member

(Missed the edit time limit)
Let's look at a positive example - a 2" th x 11" wide board of White Oak, flatsawn, with one edge jointed straight. You need to get a 5" wide rip, a 3-1/2" rip, and a 1-1/2" rip. Close, eh? You begin to worry. You start to sweat.

However, there is ABSOLUTELY no reason to think that board will bow like Chiquita's finest as you make your cuts. If it is dried properly and has no growing stress (growing stress is rare). Drying stress is far more common than growing stress.

Kick the saw on, and get your widest rip first, and watch how the blade tracks and the board slides along the fence, and then at the end of the rip, you realize how sweet it is, when it all comes together.

If the casehardening samples prove drying defect, cut your lumber people loose fast and hard. Give them no slack. If they promise they can get you the correct lumber, then why did they wait for you to wise up? If they didn't dry (misdry) the lumber, how do they control their vendor's kilns? How much did all this cost you?

10/16/22 #6: Inspecting lumber that will not cut ...

door shop guy

Pay attention..you might one day see why some boards move more than others.

11/6/22 #7: Inspecting lumber that will not cut ...

Adam

I would never assume that you can straighten an edge on a board, rip it leaving two substantial pieces. You might get away with ripping a 6" into a 5" & 1". Or not. If you go more than 1" you will unstraighten that board.

I always rough rip minimum 1/4" oversize, joint, rip. You've wasted 3/8"(kerf plus 1/4") , yet you've guaranteed you will get straighten material. I see it as simply a necessary waste factor.

I wish I could predict which one will bind. FAS Mah was always a pain that regard.

The basic explanation is wood is a very asymmetric material. As you cut it, the grain becomes unbalanced. If you made fake wood out of fibreglass & epoxy it would do the same thing. The twisted, assymetric fibre samples would move after you cut them. Your symmetric fibre samples would remain straighter.

In my opinion almost all wood moves to some degree. Poor drying only makes it worse. The grain tension direction is the fundamental cause.

11/10/22 #8: Inspecting lumber that will not cut ...

Dave Sochar

Member

I disagree with Adam - unusual, if it the Adam I'm thinking of.

Properly dried lumber, not grown under stress (large tree fell on top of it), top grade and stored correctly will not always move after it is cut.
After a lifetime of cutting Mahogany, teak, White Pine and White Oak, I have seen maybe one board in 50 move a bit after ripping. Less than 1/16" in 12' length.
The thinner the stock, the more likely to bow. Thicker stock comes from larger trees, which may have something to do with it.

4/2/23 #9: Inspecting lumber that will not cut ...

Tony

Member

You can't predict movement when ripping, other than predict some is more likely than none. If working with lumber already thickness planed by a retailer, chances are it was not done properly, and the boards may be bowed along the length, which can add to the movement when ripping. Best to work with rough sawn boards and rough rip slightly wide first, let acclimate overnight, then mill the pieces. I do all my ripping on the band saw; it doesn't lessen stress movement but is safer and can't result in a kick-back. Check out my article in current Fine Woodworking Magazine #302 page 42.

Post a Response

Notify me of responses to this thread

Subscribe to email updates on this Forum

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)

Related Information:
Products
Knowledge Base: Furniture
Shop Gallery

Recent Threads at all Forums

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

Furniture Making

Inspecting lumber that will not cut straight

FORUM GUIDELINES

Forum Posting Help

Sponsors