That helps quite a bit. Another question. Are they talking about laying down boards edge to edge to make a table top? Or are they stacking them in pairs to prevent cupping?
Regards. Max. K 4 O D S. Email: [EMAIL PROTECTED] Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with tubes group send an email to, [EMAIL PROTECTED] ----- Original Message ----- From: "Dale Leavens" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, August 02, 2007 8:53 PM Subject: Re: [BlindHandyMan] Expansion and Shrinking in Woodworking Projects > Hi Max, > > You are correct about grain running from one end to the other however if > you remember that a tree grows with concentric rings as each year growth > lays down another ring of cambium then you cut through it lengthways you > can see from the end that the grain is arranged more or less in arcs. > > So, if you cut a trunk in half right down the middle then place both flat > sides down the grain rings are in the same direction. If you then cut each > half again taking off an inch you now have two inch thinck boards and if > you set one with the original face down and the other with the original > face up then any cupping will occur in opposite directions. > > The grain still runs lengthwise. This cupping problem becomes more an > issue as boards come out of the log nearer the outer edges. > > Clear as mud right? > > Hope this helps. > > Dale Leavens, Cochrane Ontario Canada > [EMAIL PROTECTED] > Skype DaleLeavens > Come and meet Aurora, Nakita and Nanook at our polar bear habitat. > > > ----- Original Message ----- > From: Max Robinson > To: [email protected] > Sent: Thursday, August 02, 2007 9:40 PM > Subject: Re: [BlindHandyMan] Expansion and Shrinking in Woodworking > Projects > > > Ray's message contained this sentence. > > When gluing up a few boards to make a table top, not only should the > grain > of each of the boards be in the same direction and boards be matched so > that > consecutive boards have similar colors, but the end grains should be in > opposite directions. In other words, when one board is laid with the end > grain > (indicative of cupping) facing up, the next board should be facing down, > then up, and so on. This will help "balance out" any cupping that may > occur. > > I don't understand this. I thought grain ran from one end of the board to > the other. Have I missed something? Evidently. > > Regards. > > Max. K 4 O D S. > > Email: [EMAIL PROTECTED] > > Transistor site http://www.funwithtransistors.net > Vacuum tube site: http://www.funwithtubes.net > Music site: http://www.maxsmusicplace.com > > To subscribe to the fun with tubes group send an email to, > [EMAIL PROTECTED] > > ----- Original Message ----- > From: "Ray Boyce" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Saturday, August 04, 2007 10:14 PM > Subject: [BlindHandyMan] Expansion and Shrinking in Woodworking Projects > > > Allowing for Expansion & Shrinking > > Trees are comprised mostly of water. Any Boy Scout who has ever tried > to > > light a campfire with freshly-cut wood knows that such green wood is > far > > too > > wet > > to burn. This is because a tree's cellular structure is designed to > allow > > sap (which is mostly water) to flow throughout the tree. Some wood > > varieties > > literally drip with moisture when they are cut. > > Freshly-cut wood is simply not conducive to woodworking, as it must be > > dried > > considerably. This is why lumber manufacturers will either store lumber > > for > > air-drying of bake it in ovens, called kiln-drying. > > > > Ideal stock for woodworking should be at a state of equilibrium with > the > > environment in which the finished project will reside. There are a few > > considerations > > to keep in mind here: > > 1. Wood will either take humidity from or return humidity to the air. > In > > some climates, certain times of the year are much more humid than other > > times. > > The Upper Midwest of the U.S. is a perfect example: while summers are > > quite > > humid, winter air can be very dry, enough so that people will use > > humidifiers > > in the winter to put moisture into the air. This difference in seasonal > > humidity is why doors and dresser drawers will stick in the summer time > > but > > move > > freely in the winter. > > > > 2. A piece of furniture which is at a state of equilibrium with it's > > environment when it is manufactured in a humid place like Miami will > > undergo > > an eventual > > "culture shock" if it is moved to a dry location like Phoenix. > Eventually, > > the wood will give a lot of moisture to the air in an attempt to > equalize > > with > > its environment. If the woodworker doesn't plan accordingly when > building > > the piece, cracking is a very real possibility. > > How Does Wood Expand?: Knowing that wood will naturally attempt to > > equalize > > with the humidity in it's environment, a woodworker must know how the > wood > > will > > expand. Movement in a piece of stock will occur across the grain, as > > opposed > > to along the grain. That is to say, a 1x6 that is four feet long will > > almost > > always stay four feet long. However, depending on the moisture content > of > > the stock and the air (and the variety of wood used), the width and > > thickness > > (to a lesser extent) may vary considerably. > > Tips for Dealing With Expansion: When building a carcass for a cabinet, > > each > > of the four sides of the box should have the grain oriented in the same > > direction. > > As such, all four sides should grow relatively equally (particularly if > > all > > four come from the same piece of original stock). This, however, can > cause > > issues when drawers are used in the cabinet, making the drawers > difficult > > to > > open & close. This is why most cabinet carcasses are built using > plywood, > > which isn't affected by humidity nearly as much as dimensional lumber. > > When gluing up a few boards to make a table top, not only should the > grain > > of each of the boards be in the same direction and boards be matched so > > that > > consecutive boards have similar colors, but the end grains should be in > > opposite directions. In other words, when one board is laid with the > end > > grain > > (indicative of cupping) facing up, the next board should be facing > down, > > then up, and so on. This will help "balance out" any cupping that may > > occur. > > When orienting such a top on a structure such as a desk, it should be > laid > > so that the end-grains of the boards are on the two short sides of the > > table. > > To connect it the the top to the structure, screw the front side of the > > desk > > so that no movement can occur, but on the opposite (back) side, screws > > should > > be affixed in slots to allow the boards to widen or narrow. Failure to > > account for such movement may eventually lead to cracking (shrinkage) > or > > excessive > > cupping (expansion) in the table top. > > > > > > > > To listen to the show archives go to link > > http://acbradio.org/handyman.html > > or > > ftp://ftp.acbradio.org/acbradio-archives/handyman/ > > > > The Pod Cast address for the Blind Handy Man Show is. > > http://www.acbradio.org/news/xml/podcast.php?pgm=saturday > > > > Visit The Blind Handy Man Files Page To Review Contributions From > Various > > List Members At The Following address: > > http://www.jaws-users.com/handyman/ > > > > Visit the archives page at the following address > > http://www.mail-archive.com/[email protected]/ > > > > If you would like to join the Blind Computing list, then visit the > > following address for more information: > > http://jaws-users.com/mailman/listinfo/blind-computing_jaws-users.com > > > > For a complete list of email commands pertaining to the Blind Handy Man > > list just send a blank message to: > > [EMAIL PROTECTED] > > Yahoo! Groups Links > > > > > > > > > > > > > > -- > > No virus found in this incoming message. > > Checked by AVG Free Edition. > > Version: 7.5.476 / Virus Database: 269.11.2/933 - Release Date: > 8/2/2007 > > 2:22 PM > > > > > > > > [Non-text portions of this message have been removed] > > > > To listen to the show archives go to link > http://acbradio.org/handyman.html > or > ftp://ftp.acbradio.org/acbradio-archives/handyman/ > > The Pod Cast address for the Blind Handy Man Show is. > http://www.acbradio.org/news/xml/podcast.php?pgm=saturday > > Visit The Blind Handy Man Files Page To Review Contributions From Various > List Members At The Following address: > http://www.jaws-users.com/handyman/ > > Visit the archives page at the following address > http://www.mail-archive.com/[email protected]/ > > If you would like to join the Blind Computing list, then visit the > following address for more information: > http://jaws-users.com/mailman/listinfo/blind-computing_jaws-users.com > > For a complete list of email commands pertaining to the Blind Handy Man > list just send a blank message to: > [EMAIL PROTECTED] > Yahoo! Groups Links > > > > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.476 / Virus Database: 269.11.2/933 - Release Date: 8/2/2007 > 2:22 PM >
