Coping with wood movement

All wood workers require to be conscious of wood movement when building furniture projects. Failure to think about this essential element can cause wood panels to crack or split.

My higher college biology teacher compared the construction of a piece of wood with a bundle of straws. The straws signify the cells and capillaries of the wood. When a tree is growing water and food are transferred up through the cells and are carried out the tree.

Once a tree is fell the totally free water in the wood is misplaced rather rapidly but the bound water trapped in the straw like cell is slower to dissipate. As the level of bound water is reduced these straw like cells get narrower in diameter but maintain their duration. This is the basic reason that wood expands and contracts across its width but has almost no expansion duration smart.

When working with wood it is very essential to allow the wood to broaden and agreement with changes in humidity. As humidity rises the straw like cells broaden in diameter with the opposite effect occurring as the relative humidity falls.

Ways to accommodate expansion

Lets use a cutting board for the initial instance. A solid wood cutting board with a bread board edge secured with a tongue and groove joint. One edge has the bread board edge secured on both ends with a dowel through the tongue The other bread board edge is secured with the same tongue and groove joint but this finish only has a dowel in the center of the piece.

The finish secured with two dowels will develop a crack in the main panel. Because the duration of the edge piece does not change having it fixed across the width of the main panel from expanding.

Alternatively, the opposite finish of the cutting board is only fixed in the center. The main panel is totally free to broaden and agreement towards the ends. The only visual difference would be that the ends of the edge piece are no lengthier flush with the edge of the main panel.

The second instance uses a big glued up panel this kind of as a table leading. If the table leading was fixed to the rails across the width of the panel the rise and fall of humidity would undoudtable cause the panel to split.

The best technique to conquer this is use wooden clip to attach the two pieces. A 1/4″ x 1/4″ dado milled on the inside upper edge of the rails. This accepts a wooden clip that fits into the dado and is then secures to the underside of the table leading. This will safety hold the leading hold the leading onto the rails with out restricting the expansion and contraction of the big panel. With out this the table leading would gradually begin to open up.

In general whenever you are fixing 1 piece of stock across a big glued up panel actions require to be taken to allow the panel to move. Remember that it will broaden across its width but not its duration. Utilizing 1 of the two techniques mentioned above you will be able to prevent your glued up panels from splitting.

About The Author

Dave Markel is the author of “The All Wood Operating Journal”. He has aided hundreds of people enhance their wood working abilities. Visit his website at http://www.newsletterjournal.com. Subscribe to the All Wood Operating Journal at http://www.newsletterjournal.com.