Hi all. I’m a new woodworker and about to embark on my first big project. I’ve made cutting boards, barstools, etc. (all the “beginner” stuff) and my wife has recently commissioned me to build us a new dining room table. I bought some local walnut boards that I surfaced to about 5/4 by 9″ by 9′ with one jointed edge. I think the table size we’re going for is 32″ by 84″.
I’ve seen some sources say to rip large glue up boards to no more than 4″ wide. How true is that? With plenty of clamps, cauls, and biscuits, can I join these 4 ~8″ boards together, after jointing the last edge?
Please feel free to add any additional advice below. I’m still waiting for another couple of weeks to let the recently kiln-dried boards acclimate to our house, so I have plenty of time to research more tips. Thank you all for your help.
Replies
If you are confident in the kiln drying (how dry are they?) and with the 2 weeks or more of acclimation, you should be good to go with the 8" boards; particularly if they are straight when you get ready to use them. If you want to be extra safe, then rip them to 4" and mix them up so that matching edges don't go back together. I don't think the latter is necessary, but that is never absolute. (how's that for a positive statement ?)
They tested 8.5 on a pin meter, but the seller guesses they could still be 10 on the inside. They are nicely surfaced on his grizzly planer and jointer, so I trust the squareness of the boards. I'll be sure to double check when I lay them out to check grain layout. I don't doubt that the glue up can go fine with these wider boards, it's just a couple sources making me nervous. When/if I do proceed with these boards, I'll do one layup at a time to minimize any problems with the glue up
Since you are, as you stated, a newer woodworker I would like to point a few mistakes you may be making. Please don't take them the wrong way.
I am a big believer in acclimatization of wood, but it needs to be done before you joint and surface your boards. There is going to be a good chance that your wood is going to distort as you try to acclimate it now. My personal process is to buy my wood weeks in advance and stack and sticker it in my shop off the floor for at least 3-4 weeks in advance. I then do a first milling which I joint and plane the boards to within about an ⅛" of an inch of the final dimensions then stack and sticker it again for a week or so to let the freshly exposed but wetter wood equalize. Only after this do I do my final milling. Doing this I would have no problem gluing up 8"w boards. I will point out that it is very helpful to reverse the boards as tou joint the edges. This will offset the slightest out of squareness in your jointer fence helping you top lay as flat as possible and minimizing the effort to flatten the top.
The other thing is I don't put much value in absolute moisture meter numbers, what really matters is, is the wood acclimated, this occurs when the the values stop changing over a period of time. Absolute numbers mean little since the stable value in Phoenix AZ is going to be significantly different from that in Seattle Washington.
Not at all taken the wrong way, thank you for the comment! Whenever they are finished acclimatizing I will very slightly remill them to remove any small warping. I've seen the offsetting jointer trick done on youtube and I will be sure to incorporate it here. Thank you very much for the help
32" width is narrow, 36" - 40" is typical. 8 1/2 - 10 percent moisture content is fine. As far as board width goes, boards do not have to be only 4 " wide. I've built tables with 5/4 x 8" boards and it's fine. I wouldn't go any wider. The aprons on the table help to keep the top flat.
32 is a little narrow, but our dining space isn't that wide to begin with. Plus, the sawmill I got the lumber at didn't have any more boards from the same log ready to go, so I figured I can get by with 36 at the most but closer to 34 or 32. It's nice to hear that I shouldn't need to rip the boards down, I like the look of the wider boards personally. Honestly I hadn't thought of an apron, but I can see how that will act as a nearly permanent caul to help the top stay flat. I'll incorporate that into the design. Thanks for the help!
If you do incorporate an apron don't forget to allow for wood movement in the manner you attach it.
I think the wide boards will be more dramatic. I would not rip them to get narrower boards. Alternate the growth ring direction in adjacent boards when you glue up. You might consider a couple sliding dovetail supports underneath to keep the top flat and also biscuits or dominoes to help in glue-up alignment.
I'll do the alternating growth rings and I plan to have biscuits to help alignment. I also plan on doing one glue up joint at a time so that there is (hopefully) less that can go wrong.
Alternate growth rings , if the wood was ever to curve , will yield a ripple potato chip, I would rather deal with a plain chip, good framing will handle cupping across the top. With walnut, unless you want to expose sapwood, you will mostly have the planks having « U » growth rings and that’s fine, the priority goes to wood figure, alternating growth rings is at the bottom of the concerns list.
I take it that you surfaced the boards so you will be aiming at having close to perfect glue joints that only require sanding to even the top. I always glue up panels out of rough wood and plane the top afterwards, if the final width exceeds my equipment I either take the top to a custom shop or make two halves that I glue up after planing so I only have one joint to deal with. You can use wide boards, their stability has more to do with the direction of the growth rings passing through them, quarter sawn, rift sawn wood will be the more stable but flat sawn is ok as long as the cut does not come too close to the heart of the tree, if you have a plank that has small radius growth rings in the center , it’s probably better to resaw either side of the small circles and keep the outer edges. I do not use dowels or biscuits for alignment, I do a dry run and see where the wood will need to bend a little to come even, then I apply glue, lightly tighten the 5 or so clamps and use a fine adjustment tool in the form of a heavy mallet coated with thick leather to bang the wood in place, tighten the clamps and add more clamps.
Lots of good info here..
Gluing Up Tabletops
Strategies for milling, matching, gluing, and clamping large panels By Gary Rogowski #166–Nov/Dec 2003 Issue
https://www.finewoodworking.com/2003/12/01/gluing-up-tabletops
The idea of alternating the growth rings and/or ripping the boards to narrower widths is old, not good, advice, except in those rare circumstances (like cutting boards) where there is no structure to keep the glued up panel from cupping. Gulfstar is right; glue the ~9" boards together with the heartwood up, (or however the aesthetics are best), then use aprons to keep the top flat.
The other thing no-one has pointed out is that walnut is a very unusual wood. It's coefficients of expansion radially and tangentially are almost equal, so it has almost no tendency to cup (whereas with oak, the ratio is about 2 to 1, and it cups a lot.)
I would glue up the boards in pairs, then rejoint the edges (or at least check to see if they need to be improved) for the final middle glue joint.
You can get any table top of any wood to cup by allowing different amounts of moisture into the top and bottom. Apply the same finish to the bottom of the table as you do to the top; they should be sealed the same amount.
Just checking, but if you don't know how to allow for movement across the width of the top, please ask us, and we will give you several options. It is important.
Thank you for the comment! I'll prioritize the grain appearance over alternating growth rings, and I'll keep them as wide as possible. Do you recommend adding an apron to walnut table tops? I don't love the idea of an apron on the simplistic design, but I suppose a small apron could be nearly unnoticeable. If I do go with an apron, what joinery technique would you recommend so that the top doesn't split when the apron expands/contracts?
I guess we are kind of in the dark about your design. Is it a trestle table design? Or 4 legs at the corners? With 4 legs, the aprons create the racking resistance for the legs. For a trestle table, I typically use a foot, vertical board, and horizontal batten at top, one at each end, with a trestle between them (with the board oriented vertically, as it provides the racking resistance.) The batten connects the top to the two legs.
The best, simplest way to connect the battens to the top is via screws. Use a screw at or near the middle (not into a glue joint) that goes thru a hole in the batten that is a slip fit. The other screws need to go thru slotted holes (with the slots parallel to the length of the battens.) I make a lengthened counterbore to recess the screw head and washer (the washer allows easier slippage.) This can be done with a drill press and chisel, or with a more complicated plunge router set-up (unless you already have a mortising set-up for your plunge router.) Your outside screw slots probably need to be about 3/4" to 1" long, with the screws in the middle. The slots nearer the center don't need to be as long.
When making the counterbores, you should already have the screws and washers you are going to use, so you can create the counterbore depth that gives you a good amount of screw thread in the top without any chance of unfortunate drilling/screwing thru the top. Make sure your drill bit can't go all the way thru; I use masking tape applied to the bit tightly to create a stop. Drill slowly and carefully...
More questions or unclarity, just ask.
Harvey
Just noticed your question about apron dimension change. The length of the aprons is virtually constant (about 1/100th of the amount the wood changes dimension across the grain.) The problem is the change in dimension of the top, which could change a fair amount depending on the humidity control in your house. I live in humid Tennessee, and if we enjoy fresh air in the summer, we also get humidity. No problem if we plan for it, but split tops if we don't.
I believe Mike Pekovich, Ben Strano, and even Matt Kenney (way back when) recommended grain alignment over flipping growth rings. Part of the reason was aesthetics, but also for planing. If you flip boards you're also likely flipping grain direction which will make final planing difficult at best.
I've read the comments on size but urge you to go as wide as possible for your space and the wood. There are standards and design proportions to consider (check out the Golden Mean) but there's also practicality. Apologies for the mathematical assumptions in advance. Dinner plates typically run from 10"-12" in diameter. That's 20"-24" of your table top. Your plate isn't on the edge of the table so add another 2"-3" inches from the edges. Now you're at 24" to 30" of tabletop occupied by just the dinner plates. If you go with a 32" or 34" top, you've only got 2"-10" for serving pieces. Most platters are wider and I haven't considered glassware and elbows.
Good luck with your build!
Agree on
Don't rip the boards unless you want a bowling alley.
Just a post-script here. I am building a walnut gas log surround/mantel, and need to make a 25"x58" top for it. I just bought some FAS 4/4 walnut boards. 10", 9", and two 7" (one extra.) I am expecting the top to be less chaotic looking with the wide boards, and a bit easier to compose. It does help that I have a 24" jointer and a 26" planer. No, I will not be ripping the wide boards down to bowling alley size! (;-)
If you are open to a suggestion; miter-rip the widest 2 boards and do a thick return, mantels always feel better when they're like 2" thick. The boards will land at almost equal width.
Thanks for the suggestion. This particular design works better with a thinner top. I am hoping to get a final thickness at about 1". And I will have a layer of trim set in a bit right below the top that will add visual weight.
I do have 8/4 and 16/4 planks in stock for mantels over less formal fireplaces.
Rockler makes these panel clamps which could be helpful, although I haven’t used them and they’re not cheap. But if you’re going to keep making wide panels they’re another option, for those without access to a wide planer, that look like they would keep a panel flat.
https://www.rockler.com/rockler-deluxe-panel-clamp-single
Woodpeckers also has panel clamps that flatten at the same time as they provide horizontal pressure.
You can also make your own cauls that do essentially the same thing.
Mike P. does that for the dining table he made in an early FWW video series--a hayrake stretcher with the large panel resting on top of the legs. He made cauls for the top that were cambered, to apply more pressure at the center of the panel and allow for clamps at the edges to really bend the caul down there. You can also use spring clamps at the ends of the boards, which will align them--but you'll find that boards will still not lie perfectly flat along their length. You can use biscuits for that, and there are other alignment tricks. There are router bits designed to align boards on their length.
So lots of options!