Subject: rec.woodworking Changes to Frequently Asked Questions
Frequency: monthly
Supersedes: <woodworking/faq/diff_812315161@cs.rochester.edu>
Date: Tue, 30 Jan 1996 18:19:05 GMT


*** /tmp/,RCSt1a06786.Tue Jan 30 13:18:44 1996
--- woodwork-faq.Sun Jan 21 13:57:59 1996
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*** 7,13 ****
  Frequency: monthly
  
  Archive-name: woodworking/faq/faq
! Last-modified: 10/6/94
  
  Copyright (c) 1994 by James J. Roche. All rights reserved. 
  
--- 7,13 ----
  Frequency: monthly
  
  Archive-name: woodworking/faq/faq
! Last-modified: 01/21/96
  
  Copyright (c) 1994 by James J. Roche. All rights reserved. 
  
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*** 44,49 ****
--- 44,51 ----
  .20). Where can I get information about particle board?
  .21). What are some of the common woodworking terms/abbreviations?
  .22). How do I finish a cutting board?
+ .23). What is snipe and how do I eliminate it?
+ .24). How is lumber graded?
  
  
  1). Should I buy a table saw or a radial arm saw?
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*** 323,328 ****
--- 325,333 ----
  .a.  Behlens Salad Bowl Finish.  This product has been approved by
  .    the FDA for use on objects that will come in contact with
  .    food.  It produces a nice, semi-gloss finish.
+ .    (Apparently the can no longer states the FDA approval, but
+ .     product is still safe for food contact after appropriate
+ .     drying time - 12/30/94).
  .b.  Any vegetable oil. Could become rancid after a period of time.
  .c.  Walnut oil.  It reacts with the air and hardens into a true
  .    finish.  It works particularly well when the oil is heated
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*** 397,404 ****
  .The first is ftp.cs.purdue.edu in /pub/sjc/woodworking. Currently
  .it contains a list of Woodsmith plans.
  
! .The second is ftp.cs.rochester.edu in /pub/rec.woodworking. Currently
! .it contains summaries of past discussions of tools, some
  .safety related notes, and some of the FAQ postings. Below is
  .the current list of files available for ftp from cs.rochester.edu:
  
--- 402,409 ----
  .The first is ftp.cs.purdue.edu in /pub/sjc/woodworking. Currently
  .it contains a list of Woodsmith plans.
  
! .The second is <ftp://ftp.cs.rochester.edu/pub/archives/rec.woodworking>.
! .Currently it contains summaries of past discussions of tools, some
  .safety related notes, and some of the FAQ postings. Below is
  .the current list of files available for ftp from cs.rochester.edu:
  
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*** 498,504 ****
--- 503,512 ----
  .7. The Family Handyman Volume 6/94, Page 72
  ..Double Bed Futon Sofa
  
+ .8. Wood February 1996, issue #86
+ ..Fantastic Futon
  
+ 
  20). Where can I get information about particle board?
  
  .The following was provided by Stavros Macrakis (macrakis@osf.org)
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*** 612,618 ****
--- 620,755 ----
  .RAS - radial arm saw
  .ROS - random orbital sander
  .S2S - smooth 2 sides - surfaced 2 sides
+ .MDF - medium density fiberboard
  
  22). How do I finish a cutting board?
  
  .See the answer to question 13. 
+ 
+ 23). What is snipe and how do I eliminate it?
+ .End snipe occurs when the wood looses contact with the infeed roller
+ .and allows it to rise slightly from the bed of the planer. Snipe can
+ .also happen on the beginning of the board as well. Snipe can be
+ .minimized or eliminated by providing support along the full length
+ .of the board on both the infeed and outfeed sides of the planer.
+ .Proper tuning of the planer is also important in minimizing snipe.
+ 
+ .Another way to minimize snipe is to do all of the planing before
+ .cutting pieces to length. This way the only snipe loss in confined
+ .to the end of 1 piece of wood.
+ 
+ 24). How is lumber graded?
+ .
+ .The following was provided by David R. Mount
+ .(dmount@bigcat.missouri.edu) and added to the FAQ with his
+ .permission.
+ 
+ .*********************************************************************
+ 
+ .The "Encyclopedia of Wood" from Sterling publishing is a good
+ .source of this information, a synopsis of which I'll provide here.
+ . As I recall (don't have it in front of me) Bruce Hoadley's book
+ ."Understanding Wood" has a comparable treatment.
+ 
+ .I'll give a brief summary of dimensions and grading as follows:
+ 
+ .Softwood Construction Lumber
+ 
+ .Most softwoods (though certainly not all) that are made into finished
+ .boards are intended to be construction lumber.  This material is
+ .generally sold according to it's "nominal" dimension, typically 1 by
+ .something or 2 by something.  Mininum thickness for planed, dry 1-by
+ .material is 3/4"; dry means average moisture content of 12%, maximum
+ .of 15%.  Minimum thickness for 2 by material (planed and dry) is
+ .1-1/2".  For wet or "green" lumber (this includes formerly dry
+ .material that has been allowed to take up water and has not re-dried)
+ .minimum surfaced thickness is 25/32" and 1-9/16" for 1-by and 2-by
+ .material, respectively.  For widths, the rules are the same for
+ .both 1-by and 2-by material.  For widths up through 7 inches, the
+ .minimum dry, planed width is 1/2" less than the nominal dimension.
+ . So, dry 1x6 and 2x6 material should both be 5-1/2" wide.  For
+ .widths of 8" and above, the width should be 3/4" less than the
+ .stated dimension (e.g., 1x10 should be 9-1/4" wide).
+ 
+ .Grading softwoods is complex (though not as bad as hardwoods) and it
+ .depends on the use (boards versus structural lumber), and the type
+ .and distribution of defects (tight knots, loose knots, spike knots,
+ .wane, shake, etc.).  There are several different grading authorities,
+ .but the board grades most common in the U.S. are (in decreasing order
+ .of "quality") finish or select, #1 (common), #2 (common), #3 (common),
+ .and #4 (common).  Structural lumber generally uses different
+ .terminology including such things as #1, #2, and #3 structural,
+ .superior, stud, utility, and several others.  Ask your lumber dealer
+ .to explain the system by which their lumber is graded; there is a
+ .lot of variation from dealer to dealer.  The "Encyclopedia of Wood"
+ .has pictures of the board grades; Hoadley's book may also, I
+ .don't recall.
+ 
+ .Hardwoods
+ 
+ .Standard thicknesses for hardwood lumber are as follows (in inches):
+ 
+ .Nominal (green)       Dressed (dry and planed)
+ .  Thickness                  Thickness
+ .-------------------------------------------------
+      .2/4                        5/16
+      .4/4                       13/16
+      .5/4                      1-1/16
+      .6/4                      1-5/16
+      .8/4                      1-3/4
+ 
+ .Notice that 2/4 lumber is officially listed as only 5/16" planed.  In
+ .practice, hardwood stores I've been to generally sell material they
+ .call "2/4" that is actually surfaced to either 1/2" or 7/16".  I
+ .don't know why.  In my experience, the thicker sizes are typically
+ .sold as I've listed above.
+ 
+ .Hardwoods are generally sold as random widths, unlike construction
+ .lumber that has width controlled as tightly as thickness.  In
+ .general, according to the Encyclopedia of Wood, dry hardwood is
+ .sold as the next highest inch down to 3/8" shy of the nominal
+ .dimension for less than 8 inches and 1/2" shy for greater than
+ .8 inches.  In other words, a 6" wide board may be as narrow as
+ .5-5/8", a 10" board as narrow as 9-1/2".  In practice, hardwood
+ .dealers vary in how they figure width into the board foot
+ .calculation; some go to the nearest inch, some to the nearest half
+ .inch, some to the exact dimension.  Don't be shy to ask a dealer
+ .how he/she makes the calculation; you have a right to know.
+ 
+ .Grading hardwoods is *really* complex.  Grades are determined by
+ .number, width, and length of clear (free of knots and other defects)
+ .cuttings that could be obtained from the board, which is in turn
+ .determined by the number and location of defects, primarily knots.
+ . The top three grades are "firsts", "seconds", and "select(s)". 
+ .Hardwood dealers typically sell these grades together as "firsts
+ .and seconds" (known as FAS) or "select and better" (SAB).  In
+ .short, if all the defects were cut out of these boards, they
+ .should yield between 83.3% and 100% of pieces with at least one
+ .clear face.  The specific grading rules are much more complex,
+ .but this is the general idea.  Note that there has been a movement to
+ .relax the requirements somewhat for black walnut.  I also believe that
+ .many dealers sell wood as "FAS" that actually contains some select
+ .material; it's not a big deal usually, unless you need big wide long
+ .clear boards and are buying sight unseen.
+ 
+ .After these top three grades follows #1 common and #2 common.  These
+ .grades allow a lower percentage of the board to yield clear cuttings
+ .(BTW, "cuttings" means smaller boards) and allows the cuttings to be
+ .narrower and shorter than in the better grades.  #1 common should
+ .yield 66.6% to 100% clear cuttings (depending on the board size)
+ .while #2 common will yield 50% to 66.6%.
+ 
+ .A couple notes about #1 and #2 common boards.  First, they are often
+ .not displayed right out front by a hardwood dealer; if you are
+ .interested in lower grades, ask about them.  #1 and #2 boards can
+ .sometimes be a better buy; they are generally 20 to 70% cheaper
+ .than FAS boards so the cost per square inch of clear lumber may be
+ .lower if obtained from lower grade boards.  Of course, this requires
+ .that you can use smaller pieces; you also have to figure in the cost
+ .of your time to cut around the knots.  On the other hand, in more
+ .casual pieces I often leave some knots in the finished piece if
+ .they won't cause structural problems.  Some of the most beautiful
+ .figure occurs near knots.  Each person will weigh these variables
+ .differently.
+ 
+ .*********************************************************************
-- 
Jim Roche
roche@cs.rochester.edu
University of Rochester Computer Science Department Rochester, NY 14627
