how to join 4 oak slabs together

[SylB]

Hello,

Recently I got some oak slabs and decided to make a tabletop. Roughly 85 inches long and 26-27 inches wide with one live edge. This is by far the biggest project for me. I've done some basic building before, like a console table or Adirondack chairs, but nothing of that caliber. 

None of the oak slabs are even, neither are the cut edges. 
Do I begin by roughly sanding the surfaces of the boards with a planer and then edges before joining them?
What's the best way to join? Glue? Biscuits?  And if biscuits then what size? 


 

Thanks!

[Old Greenhorn]

Welcome to the Forum!
 I am not a 'real woodworker' but I dabble a bit. The real folks will be along shortly with good advice. But I can hit some basics.

Any joined edges must be dead square and dead flat, so joining the edges is pretty much required unless you have a really good straightline saw. 
 Biscuits are meant for alignment only, not joint strength. They won't help hold it together.
 The edge joints will be fine with just glue, the end joints will soak up too much glue and not, in my opinion, have any meaningful strength. Is it possible to consider staggering the boards to improve strength? DO you need the full length of the existing boards, or could you overlap them by half their length?

The basic process for me would be to plane the boards all the same exact thickness, joint the edges, cut the ends dead square. The glue it all up. But those end jints are your challenge. The only reproach I can see if the add a skirt around the bottom to support that long run. You might also add a blind spline inside the end joints, that will help a bit, but that is tricky and I would still have a skirt underneath it.

 Now as woodworkers go, I am more of the woodbutcher here, so let's wait for the smart guys to come along and give you some real help.
 I wish you the best, keep us in the loop as you move along. You can do this, just think it through and take your time.

[firefighter ontheside]

Tom says he's a wood butcher, but he's right about your table.  The first thing to do is make the 4 slabs flat and the same thickness.  Then you need all straight edges.  What do you have to work with.  I'm guessing you don't have a jointer and maybe not even a planer.  Those are what I use to get flat and straight.  To get one side flat I would make a sled to put the pieces on to run thru the planer.  Then you take them off the sled and put the flat side down.  

As far as gluing the ends, butt joints don't glue very well.  Like Tom said, the end grain soaks up all the glue.  I think you can apply glue to the ends and let it soak in and then apply more glue before bringing the pieces together.  This will be ok to keep the ends connected, but it will not provide much strength.  For that you would need the table to have aprons under the top for support.  A piece going across the underside of the table from apron to apron would help support the butt joint.

Generally, tables are not built the way you want to do, but woodworking is an art and if you want to try it, I say give it a go.

[TroyC]

I might try a lap joint or tongue and grove on the ends. After that, square up the long boards and use a good quality glue. I use the Premium Titebond and have good luck with it's holding power.

[metalspinner]

Long, heavy tenons on the ends of the joined pieces should be fine to hold them together. But that will assume you will be able to get everything flat and square to begin with. 
I would use a router and template to  route mortises into each adjoining end. Then cut a loose tenon to fit and glue it together with long bar clamps. 

[doc henderson]

I agree with good glue (Tite bond is what I use), I like the half lap, and you can offset the two sides.  some big equipment will help but can use a router and sled if needed.  make sure the wood is dry.  if it is over 12%, it will self-destruct as it dries (warp, crack, twist, split).

[Old Greenhorn]

See? I told you the smart guys would come along. :D
 We don't know anything much about what you have to work with or you skill level. Mostly available tools and machines will take a big hand in how you approach this project. I think that tenon idea is good but it's tough to get a tenon very deep ( I had mentioned blind spline which is nearly the same thing with a bit more precision). Firefighter on the sides' idea of end gluing is one I have tried in the past and it will work better than just straight gluing, but as he said, there is not much strength there and on a finished table would likely not make you happy. Of all these I like the lap joint, especially if you can make a long lap. The issue of end gluing goes away.

 SO you are brand new to the forum and I'm not sure how much you have read around here, but here is how you can get the most help. Feed us with more information about what you want and how you can get there. I note that we don't know how thick this wood is. Also the one lve edge you have is going to be tricky to match up at the joint. What is the wood species, white oak? If these boards are only 1 or 1-1/2 inches thick it becomes a different ballgame than if they are 2-3". Hard to tell from the photos but they might be 1" boards? If so, things change. 7' is pretty long for a table, is that your final desired size?
 Tell us more so we can help you more.

[metalspinner]

Jointing a good glue edge on big, heavy boards is tough if you have a normal  sized jointer...6"

On big stuff, I like to use a router and a straight edge. The "straight edge" doesn't have to be perfect. Route the edge of the first board following the straight edge with a guide bushing in the router. Then move the second, mating board into position and route that edge moving in the opposite direction. 

I like to use an up it 1/2" spiral bit. The edges that are routed are
Complimentary, so the edges come together perfectly and invisibly. Any irregularity in the "straight edge" keys into each other perfectly. 

[Ianab]

I've done that sort of stuff with my "router bridge" planing setup. While it's designed to flatten table top slabs, if you clamp a board down at 90 deg, it will also joint those edges just fine. If the board is heavier than the tool, then clamp down the board, and move the tool (on nice straight rails) 

Then I router some slots in the boards to help with alignment with some small floating tenons. Not strictly needed, but helps with the glue up. Wood has to be dry of course, the more movement you have, the more chances of failure. 

[DMcCoy]

It's just me but I see 2 tables,  one with 2 live edges the other straight edged.
As it is laid out I see a bar top.  I would half lap the ends and dowel the edges. 
A router sled would be my choice for flattening and edging.

[WV Sawmiller]

   Us hackers would probably plane them the same thickness and try to square up the edges then put a half inch piece of plywood under the bottom. :

[boonesyard]

You've received a lot of good advice via the responses here. The only thing I would add here, not knowing what equipment you have to work with, is another option to square up your edges if you don't have a jointer. Once you have the slabs flat and the same thickness, you can use a track saw or circ saw with a good blade and straight edge to double cut. Put two slabs on a sacrificial surface and clamp them so the edges to join are as tight together as you can get them. Then set up your saw and straight edge so you cut right down that line, actually cutting both slab edges at the same time. Depending on how much gap you start with in spots, you may need to readjust after each cut and do it 2 or 3 times until you're cutting both slabs all the way along the joint. This method works quit well if you have a good blade and a saw that can cut all the way through the slabs. 

[doc henderson]

that works well, but after you get them close, they need to be fastened to the board underneath, and not clamped toward each other, or it will pinch your blade.  



 

 

 



same technique used to tighten up this wide miter.

[DMcCoy]

Beautiful work Doc H.

[doc henderson]

spalted and blue stained quartersawn sycamore, with epoxy and pine nut filling.

[kantuckid]

Joining end grain is one thing, such as via T&G (like flooring) or using dowels, but asking it to be strong is another.
End grain not gluing well is more about the wood grain aspect than it soaking up the glue-it just has little strength even if you flood the glue join as  the fibers are not aside each other.  
The troubling aspect once you've joined those ends is that you're asking the ends to allow wood movement across quite a width of wood. I would not expect a great result over time with boards that size.

Honestly, if your stuck on building something that length, I'd try to come up with other, "new" boards, the length of the table & use these ones for the aprons or other table parts? 

I'm guessing you want those board faces to be "surfaced" as finished lumber, but keeping one natural slab edge? 

I will say that there are millions of table tops and other stuff made in China with end joined wood out there, but sure not how a home shop does things. But they use very narrow strips of wood to join into larger panels. 

You need a slab like Doc's! ;D 
  

[kantuckid]

spalted and blue stained quartersawn sycamore, with epoxy and pine nut filling.

WTH is pine nut filling? ???

[Old Greenhorn]

I think what we have here is a one post wonder. The OP has only come back once to check his thread, left no comment, and hasn't been back in two days. It's a shame. He got about $500. in free and good advice and won't capitalize on it. Must have been something we said? :D ;D

[Iwawoodwork]

As I am a woodworker with very limited tools, I would assume that you have at least a hand held router, so first build the router table, side runners at least a foot longer than the proposed table top and 1/4" to 1/2" taller than your thickest board/slab, then mount your runners to the base (a sheet of chip board, Masonite, particle board, plywood etc.) spacing the runners far enough apart to allow the widest board/slab to fit between then you construct the router sled to  slide up and down the runners and the router across the slab that way you can get a level slab, also could use the same method to square the edges by using taller runners and clamping the slab/board to the squared runner.  A lap joint could be cut using the router sled also.   

[kantuckid]

Don't be too quick to judge the OP? He might be an OTR truck driver, work many hours as I once did, or have 8 kids or whatever? We simply don't know. 

Those joined end boards I've seen in both mill work (really common) and Asian Rubberwood table tops (also really common) all mostly has finger jointed ends to create aligned grain glue bonds. 
I wonder just for curiosity sake- what you'd get with OP's 4 boards that used a lapped end joint made well and true with either a router or dado blade set-up? Using like a 1.5" lap width and then after glued doing a regular edge glued table top slab?  If much attention was paid to the apron design, and underneath support system, it just might stay together pretty well.  

[kantuckid]

As I am a woodworker with very limited tools, I would assume that you have at least a hand held router, so first build the router table, side runners at least a foot longer than the proposed table top and 1/4" to 1/2" taller than your thickest board/slab, then mount your runners to the base (a sheet of chip board, Masonite, particle board, plywood etc.) spacing the runners far enough apart to allow the widest board/slab to fit between then you construct the router sled to  slide up and down the runners and the router across the slab that way you can get a level slab, also could use the same method to square the edges by using taller runners and clamping the slab/board to the squared runner.  A lap joint could be cut using the router sled also.  

I have used my 4x24 Bosch belt sander on large slab type surfaces to maintain thickness rather than one of my several routers. I've even used radial arm saws, many times in fact, to create a true flat surface. 
A hand plane was the tool I was forced to joint edges with in 7th grade, like many kids, it was hand tools or nothing which is the best beginning and perhaps the more creative end as well. Lots, meaning "too many of tools", is a disease many folks get, while ignoring technique. I'm not limited but i try to avoid wasting space and moolah. 

[doc henderson]

he (OP) may have been curious and after posting but then forgot his password.  but he did get a pic in the thread, which is a learning curve for many.  he also may think no one will reply, at for some time.  Our forum tends to be quick to try to help new members.

[kantuckid]

I for one, enjoyed the discussion, OP or no OP, wood freaks are like that? :D

[Stephen1]

I really like seeing what you guys produce from the slabs. I saw and dry. When people send me pictures or I see what a finnished product from my work, my comment is ussually. I didn't Charge Enough. The wood looks better finished than it did when I opened that log. 

[Brad_bb]

Joining boards end to end isn't done much.  Generally doesn't look very good, but one way to make it look good and work would be to use a strip of wood between them (grain running perpendicular to the slabs).  This strip could be straight or S shaped or curved.  you then use kreg jig screws to to screw the two halves of the top to the divider strip.  Depending on the thickness, you'll have to see how strong and rigid it is.  It may be necessary to add reinforcement on the underside.  You could add a routered in metal plate, or maybe bowties?  

Keep in mind this assumes you glue up each half first at the parallel grain glue joint.  What I'm talking about above is joining the end grain to a divider strip.  The strip can be a contrasting wood like Walnut, Ebony, purple heart etc. or it could be the same type of oak.