How do you make a perfectly flat solid table top wider than your planer?

[Michael Yadfar]

Sorry if this sounds like a dumb and simple question, it probably is. But I'm thinking of building a solid oak table top that will be about 3' wide. This is a step up from my usual projects; I've built solid pieces like cutting boards and even small table tops. All of these things though weren't wider than my planer so I just sort of rough planed the boards and ran the whole thing threw after the glue up.

What I assume I would do is run through each single board on the planer at the same time to final thickness, so that way they're guaranteed the same height. Then I would glue them up very carefully; making sure everything stays completely flat. Then after that I guess I would scrape off excess glue and orbital sand it.

[Andy kerra]

Yes that will generally work. I have done a number of table top surfaces that way. The only issue becomes getting any discrepancy in the elevations of the boards after the glue up to be even. That's where a good large hand plane will come in handy.

After years of doing it the way you proposed, I got a no7 jointer hand plane to do table tops with and man does it make a difference ( there is a bit of a learning curve though).

[Kevin Jenness]

Yes, that's the way. Biscuits will keep the boards more or less in line. For better alignment cut stopped grooves with a slotting router bit registered from the face with tight fitting splines. If you have access to a shop with a wide belt sander it will save you considerable elbow grease. If you are using numerous boards in the top you may want to glue it up in sections that fit through your planer, then glue up the sections.

[Loren Woirhaye]

Dowels. They align better than biscuits. People are using Dominos too these days but the tool cost is extravagant when dowels will do.

Or take it to a shop with a wide belt.

[Peter Quinn]

Joint the widest boards you can on your jointer, glue these up to the wides sections you can put through your planer, plane to final thickness, glue these sections up very carefully with cauls and perhaps alignment aids like biscuits or splines, level with hand planes or belt sander, card scraper, ROS. I've done tops over 5' wide this way. Perfectly flat? Probably not, but flat enough to convince the eye and keep a drink level on a dining table. Don't skip the cauls. Biscuits might help keep the sections in the same plane, but add enough clamping pressure and you can create a pretty good bow in the top like an airplane wing that will remain post glue up, that is way more difficult to fix than slight level issues...PDAMHIK!

[Peter Keen]

You have the right idea.

I've now done over a dozen table tops, all 20" wide or larger, using a 6" jointer and 12" planer, without biscuits. I jointed the boards flat, then carefully glued them up. All required some handplaning or orbital sanding afterwards, as the boards were never quite exact. You can joint boards wider than your planer if you use a sled. If you are powersanding these items, then a belt sander with 120 grit will be a good place to start to get your boards rough sanded to flat - I found sanding took too longer with an orbital sander....Ultimately I learned to use handplanes, as I found them faster, doing a better job, than the orbital and belt sanders.

[Michael Peet]

The way I do it is make sure the pieces are the same thickness, then glue together with cauls:

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The cauls will keep the panel pretty flat and should reduce the amount of cleanup work. I do final flattening with a hand plane.

Check out Mike Henderson's writeup on making and using cauls (http://www.mikes-woodwork.com/Cauls.htm). They are really useful for making panels.

Mike

[nicholas mitchell]

Glue it up in 2 or 3 sections, whatever you need. Run each section through your planer then glue them all together. This way you'll only have 1 or 2 glue lines to deal with.

edit. I see I'm a bit late to the party with that idea. Ha!

[Frederick Skelly]

That's where a good large hand plane will come in handy. I got a no7 jointer hand plane to do table tops with and man does it make a difference ( there is a bit of a learning curve though).

+1. That or find someone with a wide-belt sander. Maybe a cabinet shop. Ive done it that way.

[Jon Wilson]

+1. That or find someone with a wide-belt sander. Maybe a cabinet shop. Ive done it that way.

+1 I take any glue ups that I have to a local mill. They have a 48" planer & a 48" drum sander. I ask them to send the board through
each, one time on each side, planer first, then drum sander. The charge me a couple dollars and it takes just a few minutes.
And saves me a lot of time in the shop.

I would guess a mill or cabinet shop would be willing to do the same.

[Tai Fu]

If you can't find someone with extremely large planer/drum sanders, you can always use a router sled. That was how I leveled my workbench top. It's not perfect and there is a slight concavity from the router sled bowing under the weight of the router but it looks flat enough.

[glenn bradley]

What I assume I would do is run through each single board on the planer at the same time to final thickness, so that way they're guaranteed the same height. Then I would glue them up very carefully; making sure everything stays completely flat. Then after that I guess I would scrape off excess glue and orbital sand it.

I have been doing it as you describe for years but, I am a very light user of the ROS. Overused it can add more irregularity than it removes. I mill the boards to slightly oversize, glue up with or without splines depending on size and intended use, I clamp for an hour or less and then skin any squeeze out off with a chisel (I am not in the wet rag camp on squeeze out cleanup).

I generally let large panel glue-ups set overnight and then scrap any residual glue off with a cabinet scraper. At this point your panel should be fairly flat. I work the material to final thickness/surface appearance with a hand plane, card scraper or sand with a large sanding block to present a reliable abrasive surface to the material. The ROS follows contours as opposed to correcting them so for flattening it is not my choice; for smoothing it can be useful.

[Prashun Patel]

I've used dominos and dowels for alignment, but in the past year, I've been using cauls. Once made, they're quicker and better for alignment than other methods. If you don't have cauls or other the previous alignment tools, but you do have patience, you can glue up the boards one by one so, which will allow you to align the joint with your fingers while clamping.

As for flat, a couple things to know about big table tops: 1) they can cup and twist after glue up, 2) If you want to flatten with hand tools, you will need to pay attention to grain direction - something you should do anyway if you plan to finish in a way that pops and highlights the grain, 3) table tops don't need to be perfectly flat; they only need to look flat to the eye.

(3) is a liberating point: Do your glue up, scrape away the dried glue joints, and then set it atop your base. You can flatten the bottoms locally so that there are no unsightly gaps between the apron and the bottom. Then, inspect the top for visual flatness. In many cases, you won't need adjustment. Also know that tiny twists may be pulled flat when the top is screwed to the base.

If you do require flattening, then be very careful with your orbital sander; resist the temptation to tip or focus on a spot. ROS's CAN be used to level things a little but think 'feathering out differences', not 'flattening high spots'. Your deftness with the ROS is more important the higher the sheen you plan to put on the table. A high gloss table will telegraph all your heavy handedness with the ROS - not just swirls, but dips and valleys. And you won't notice it until you get several coats into your finish. To this end, consider now the finish you will put on the table. On oak, a glossier finish requires a lot of prep and filling. An in-the-wood, satin finish is more forgiving with things like open grain and less-than-perfect flatness.

I have used a commercial milling service to get a countertop prepped. It cost me about $50. The issue is that a drum sander (assuming you can find a place with one > 24") won't joint the table; it will only thickness it consistently. Also, you will still need to go to town on it after with a ROS to prep it for finishing. This is not as trivial as it sounds; the drum sander leaves drum marks that can be hard to see until the first coat of finish goes on.... DAMHIKT....

[Michael Yadfar]

What exactly is a caul? After looking it up, it seems to me that all it is is two 2x4s clamped together with the table top in the middle so it stays flat. For some reason I have a feeling that this is a bit more complicated than that...

This table top is sounding a bit more complicated than I anticipated too with things like bowing and scratches to worry about. I don't even know if I'm going to build the base, I may try to reuse the one from my current living room table. The reason I want a new table is because the current one is pretty beat. It's not even worth refinishing because the top is just veneered plywood. Whether or not I replace the whole thing or just the top is still debatable, but I feel I can handle both. I may play around with a few more small projects first though, because we are talking about a table that's around 3'x4', a mistake that big won't be cheap!

[Prashun Patel]

Don't be talked out of this by us all. In the end, you can certainly just follow your initial instincts. I certainly did that when I was starting and much of the time, I got great results. Not perfect, but still wonderful. So, if you still have the hankering, go for it!!!

Cauls are exactly what you say, but they're jointed flat or slightly 'cambered', or curved such that the touch in the center and have gaps about 1/8" (not critical) near the edges. When you pinch the ends with a little clamping pressure, the lever exerts even pressure along the width and keeps your joints as flush as can be. You can make them out of 2x4's or any hard/soft wood scrap you have.

I say do your table. There's no complicated joinery or hidden rabbit holes that you may get stuck in.

[Jerry Thompson]

Go to Mike Henderson's blog. He shows how to make cauls. They work great to keep things flat. Remember to dry fit first.

[Geoff Barry]

You have two separate issues : (1) how do you glue-up a flat tabletop, and (b) how do you keep it flat :)

I made a dining table 42" wide - I ran the boards individually through the planer, but did all boards at the same setting each time before changng the planer height (minimized measuring error in producing the same thickness). I used biscuits for alignment, and then clamped cauls - in my case, merely 1x6 boards with one edge jointed - edge-on every 16" or so to hold it flat while the glue dried. I used breadboard ends to keep it flat going forward.

[Jim Andrew]

It really helps to use rough sawn lumber, joint it flat, plane it thicker than needed, then square up the edges and glue it up in panels your planer can handle, run it through one time, and then look at putting the panels together. Personally, I run the finished panel through my thickness sander, it is only 15", but will sand a 30" panel by just reversing it and putting it back through. Amazing how flat the panels are after using this sander. If I needed a wider panel, would take it to my friends cabinet shop. They have a 37" wide speedsander.

[Shawn Pixley]

Glue up with cauls. Flatten with hand planes - jack, jointer, and smoother

[Jim Matthews]

If you're really stuck, and don't know your way around handplanes,
use a router on a planing "sled".


http://www.youtube.com/watch?feature=player_detailpage&v=DezxCIl6ynM

You've got to make sure that the base of the jig is flat, and stable under the weight of your router.
A bit with a rounded profile is recommended, to keep tear out at a minimum - they take longer, but leave a smoother surface.

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[Jack Lemley]

Dowels. They align better than biscuits. People are using Dominos too these days but the tool cost is extravagant when dowels will do.

Or take it to a shop with a wide belt.

+ 1 on the dowels but i would add the Dowelmax to be priceless for accurate alignment!

Jack

[Michael Yadfar]

Does anyone know a lot about keeping the table top flat? It's an issue I never even thought of, the table top warping. The way I've traditionally done this is I kept the boards under 4" wide and alternated grain direction. I don't know if there are any other measures I have to take for a table that's going to be this big. The biggest solid oak table top I've built so far was only 18" x 22"

[Rich Engelhardt]

A bit with a rounded profile is recommended, to keep tear out at a minimum - they take longer, but leave a smoother surface.
The articles I read in the past said to use a wide bottom cleanout bit.

Wouldn't that rounded bit take forever to use on a wide table?
3/4" at a time is bad enough, but man, we must be talking taking off 1/8" or less with each pass w/that rounded bit.

Anyhow I was also going to suggest the router sled.

I wonder also if one of those orbital type floor sanders you can rent would work?

[Ruel Smith]

A caul is any sacrificial board for clamping. It can be trued, or "sprung" by tapering the ends or.the middle. If you want a trued glue up using cauls, you want to use a sandwich of trued up calls on the glue up, with sprung ones on the.outside for clamping pressure. Place the calls at each end and one in the middle. You would never want to use a sprung caul without it pressing on a true caul for truing the top, else the glue.up will not be true. Work your clamps together a little at a time, both side and.top clamping.

[Steve Peterson]

I would joint the ends that will be glued and use a router sled. Planing them before glue-up will just make the finished product slightly thinner, at least it does for me since I usually end up with a less than perfect glue-up.

One trick is to take 2 pieces that will be glued together and run them back to back through the jointer at the same time. That way if the angle is not exactly 90 degrees, the other board will compensate.

Also, alternate the ring pattern so that if one board has growth rings cupping upwards, the next board will cup downward. This will help minimize movement in the finished product.

Steve