Wood Expansion question

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Forum topic by twobyfour16 posted 11-26-2010 07:36 PM 2961 views 0 times favorited 6 replies Add to Favorites Watch
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69 posts in 3724 days

11-26-2010 07:36 PM

Topic tags/keywords: bench workbench question joining wood expansion seasonal

So, I’m slowly working on building my workbench. So far, I have the top laminated up, along with some other components for the trestle base. I laminated my benchtop with 62 pieces of hardwood that are about 3/8” thick and 3 1/4” wide. The top is now about 24” wide & 7 ft long. I plan on putting a skirt around it, like most folks do, as well as a face & twin screw end vise. So here’s the question: With the top laminated from so many pieces, am I going to have more or less seasonal expansion across the width of the bench? I’m going to attach the end skirts with a tongue on the benchtop & groove in the end skirt. Do you think I can get away with gluing it the full width, or is that asking for trouble? I want to avoid using barrel bolts & make the entire bench out of wood.

-- Allan, Portland, OR

6 replies so far

View GaryL's profile


1099 posts in 3070 days

#1 posted 11-26-2010 07:42 PM

Your still going to have the same amount of expansion and contraction as if it were a solid piece of hardwood. It will be more structural stable though because of the multiple laminations. The end skirts will still need to be designed with movement in mind.

-- Gary; Marysville, MI...Involve your children in your projects as much as possible, the return is priceless.

View RalphBarker's profile


80 posts in 3009 days

#2 posted 11-26-2010 07:48 PM

I agree with Gary. You likely won’t have a lot of expansion across the end of the bench, but you’ll still have some that needs to be accommodated.

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Bill Davis

226 posts in 4163 days

#3 posted 11-27-2010 12:27 AM

Wood is hygroscopic which means it take up moisture and give up moisture as the %RH increases and decreased. In doing so the wood will expand and contract and even a good finish will not prevent that, only slow it down. Wood expands roughly twice as much tangential to the growth rings as it does perpendicular to them and a negligible amount along its length. With a lamination the grain directions are mixed so that will mitigate swelling and shrinking but not eliminate it. How much expansion/contraction occurs is pretty hard to estimate so take some moderate precautions in fastening the skirt especially across the end grain.

Beautiful piece. Will make an envious workbench.

View twobyfour16's profile


69 posts in 3724 days

#4 posted 11-27-2010 02:46 AM

Thanks guys. I appreciate the input. I think I will glue the end skirts on one side, and fasten the other side with a barrel bolt with an elongated hole to allow for expansion. Better safe than sorry. The top has been in my garage for a couple months now & I regret not measuring the width exactly – it would have been a good experiment to see how much expansion I get. It was hot & relatively dry when I finished laminating the top in july or august, and is cold & wet now. Live & learn….
Thanks again.

-- Allan, Portland, OR

View wseand's profile


2796 posts in 3281 days

#5 posted 11-27-2010 03:24 AM

GO DUCKS…....!!!!! That is all. he he.

View Lumber2Sawdust's profile


139 posts in 3105 days

#6 posted 11-27-2010 05:44 AM

I agree with others here. You will have to allow for movement. I recently completed a similar bench. To allow it to move, I glued the first 3-4 inches at the front of the apron, then pinned the tongue at a few places along the length, with elongated holes to allow it to move. I used walnut dowels for the pegs to highlight the contrast. It worked well with some of the other bits of the bench.

EDIT: You can see the pegs in my bench top in my project, posted here.

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