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Forum topic by RontheEskimo posted 02-23-2010 06:20 AM 1268 views 0 times favorited 10 replies Add to Favorites Watch
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RontheEskimo

4 posts in 2490 days


02-23-2010 06:20 AM

Hi Everyone,

I started destroying expensive pieces of wood in my garage about a year ago and was hoping someone with a little more experience could help answer a beginner’s question. I’m about to start on my fist project that will (if all goes according to plan) be allowed in the house. I’ve designed a book case with much inspiration from other lumber jock postings (thank you!) and am hoping someone can tell me if I should be worried about wood movement. My apologies for not posting a picture, but I don’t have a copy online and it seems that you can’t upload in a forum.

I will have shelves that are 16×38 made of 5 edge joined 3/4” maple boards. Around that I will have a 3/4” cherry apron held to the posts with mortise and tenon. I’d like for the top of the boards (aka the surface of the shelf) to be flush with the top edge of the apron. Am I asking for trouble by framing the shelf? I thought about trying to make the shelf a floating panel but really don’t want a lip.

The book case will be in Illinois in a home with central air and heat… Unfortunately, I have no idea what that means in terms of humidity.

Thanks for the help!
Ron

-- Ron's Woodworks (Naperville, IL) - specializing in hand crafted sawdust and firewood


10 replies so far

View popmandude's profile

popmandude

109 posts in 2482 days


#1 posted 02-23-2010 01:14 PM

Howdy Ron. Like you, I am only a small step above rookie. But here is what I can tell ya. In order to capture a panel inside a frame, and keep everything flush, most people will veneer some good quality plywood. Solid wood expansion will blow out the frame. There are alot of expansion calculators on the internet that will tell you how much you can expect a solid wood panel to expand.
Good luck
Randy

View bent's profile

bent

311 posts in 3131 days


#2 posted 02-23-2010 01:26 PM

ron’s right about the plywood being more stable with humidity changes, it’s also (probably) cheaper and quicker to use in this case.

something else to consider: i’ve heard that as a general rule, a shelf over 36” will bow unless supported in the middle.

View Dennis Fletcher's profile

Dennis Fletcher

467 posts in 2516 days


#3 posted 02-23-2010 02:13 PM

I’ve built many shelves over 36” and your right, bent, there tends to be too much weight for a 3/4” piece of wood. I have done some creative things to stop this, but the support in the middle works best.

-- http://www.ahomespecialist.net, Making design and application one. †

View richgreer's profile

richgreer

4541 posts in 2536 days


#4 posted 02-23-2010 03:53 PM

Let me chime in and endorse the advantage of putting veneer on plywood. That will be much more stable and you won’t have to worry about movement. However, I also want to add that properly glueing veneer to a 16×38 piece of plywood is not a simple, easy task. You need lots of clamping pressure distributed evening over the entire board. The ideal way to do this is with a vacuum press. If you do not have a vacuum press you will need to use a lot of clamps and cauls. The cauls should have a very slight curve on the bottom so that the clamping force in the middle is sufficient. I’m saying all this because you are claiming to be a rookie and, therefore, you may not be aware of what is needed to properly glue veneer.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View bob101's profile

bob101

289 posts in 2912 days


#5 posted 02-23-2010 05:49 PM

I have constructed a book case and posted it, what I diid was use ply for the shelves and to stop sag, I applied an apron to the front of each shelf and it is loaded heavily with books and has 0 sag and was built over four years ago( i have pictures posted under my projects, feel free to look)It is probably 39 or so inches across.

-- rob, ont,canada

View Gofor's profile

Gofor

470 posts in 3249 days


#6 posted 02-24-2010 02:29 AM

The wood will move, expanding mostly across the grain. Central Illinois gets some major humidity changes, with the humidity in the winter getting very low (so you pick up static from the carpet in the winter?) . The high humidity in the summer is somewhat mitigated by the AC, but does not drop it near as low as the winter.

For your design, you could drop the shelves into a 3/8” wide rebate in the top of the cherry apron, depth to equal the shelf thickness. Glue only the center of the ends, and use table top clips (http://www.americanfurnituredsgn.com/Table%20Top%20Mounting.htm) to attach the rest. I would recommend the wood ones shown, not the metal ones. Make the dado in the sides deep enough so the clip can move in and out. Make the shelf with about 1/16” clearance on each side (1/8” overall narrower width).

Make sure you finish the shelves top and bottom the same. This will equalize moisture gain/loss so you don’t get any warping.

HTHs

Go

-- Go http://ncwoodworker.net/pp/showgallery.php?cat=500&ppuser=730

View Jim Crockett (USN Retired)'s profile

Jim Crockett (USN Retired)

852 posts in 3195 days


#7 posted 02-24-2010 04:51 AM

What’s a ‘fist’ project – is that one where partway through you get disgusted with it and put your fist through it? Just kidding – welcome to LJ and sounds like the advice you have received is good.

Jim

-- A veteran is someone who, at one point in his/her life, wrote a blank check made payable to "The United States of America," for an amount of "up to and including his/her life".

View RontheEskimo's profile

RontheEskimo

4 posts in 2490 days


#8 posted 02-27-2010 04:37 AM

Thanks All for the help. I had already bought the wood by the time I asked the question – and I don’t think I’ll get the ok for another trip to the lumber store so I’m going to have to make due with solid wood one way or another. I guess it’s a good problem to have, right?

Thanks Bent and Dennis for the thoughts on the wood bending. Originally I’d planned to dowel the shelf all the way around to connect it to the apron so I thought I would be able to get away with that but it looks like it won’t be the case anymore and will need to use a support as you suggested

Rich, I’m with you. I don’t know that I’m ready, willing, or able to tackle vaneer just yet. I bought a couple of those cool table top clamps but haven’t figured out how I’m going to cut a “slight radius” into the cauls just yet.

Gofer, I appreciate the advice. I’m really partial to the apron being 3/4” thick so I think I will actually glue another piece on the inside of the apron to, in effect, give me the dado you’re talking about. Then use the table top clips as you suggested. Does anyone see any issues with that idea?

Again, thanks all for the help!

...oh, and Jim, this is my “interview” project. The wife said if it comes out right I get to build a matching dresser and crib. No, she’s not expecting yet, I just figure it will take me the next three years to build all that (and to pay for the wood!) So far, all my other projects are either awful little boxes or tools and jigs, haha!

-- Ron's Woodworks (Naperville, IL) - specializing in hand crafted sawdust and firewood

View Gofor's profile

Gofor

470 posts in 3249 days


#9 posted 02-27-2010 11:29 PM

Gluing a cleat on the inside as you described is actually a simpler and stronger fix. Good thinking!!

Go

-- Go http://ncwoodworker.net/pp/showgallery.php?cat=500&ppuser=730

View TopamaxSurvivor's profile

TopamaxSurvivor

17664 posts in 3138 days


#10 posted 02-27-2010 11:41 PM

I’m an advanced rookie I’d say. The one thing that is loud and clear reading LJ posts is “wood moves!!”

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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