edge join two 17' boards for conference table

[David Bowen]

I have two 6/4" x 20" x 17' long white oak boards for a conference table top. After considering plunge saw prices, stability of 17' straight edges, router drift and chipping I am down to one method. I would love help by way of more suggestions.

My plan is to rough straight line the two planks and lay them side by side the way they will be glued up. The gap in the middle will be 1/8 less than the width of the (sheering?what is best here?) router bit. The boards will be clamped in this position and a couple of plywood pieces - factory straight edges - will be hot glued down with a mason line string for best straight as I can get.

The router will go down the middle of the two boards. Hopefully no drifting, but any minor drift or out-of-straight will be cancelled by the resulting mirrored cut.

Improvements or comments much appreciated

Thanks,
David

[Steve Rozmiarek]

You could do the same thing with a saw. You might have to reset a time or to so it cuts both planks. A router cutting on both sides of the bit sounds a potentially unstable. How much need to come off?

[Bobby O'Neal]

I doubt I have any great ideas but whatever you come up with, I think filming it and posting a video would be awesome!

[Mike Cutler]

David

If it were me, I'd rip them as close as possible, clamp the faces together, and finish off with a #7 or #8 jointer plane. You'll have to make an edge guide for the planes though.
What you want to do is fairly easy, it's just the size and weight of the material that presents the challenge. Those are some big boards.:eek: How are you going to plane them when joined?
You don't list your location, which might aid you if you did. It's entirely possible that a member is near you that can help you.
If you're close to the Connecticut/Rhode Island border I can help you out.

[David Bowen]

thanks steve, yes I'd rather have the stability of a saw in the plan. I was so worried that it has to be $$ plunge saw that I thought maybe using the right router bit would be stable. good blade on my milwaulkee circular saw? don't know. a nearby shop has a straight line rip saw, again, would the edges be good enough?

[Mel Fulks]

That could work ,but if you have access to a large jointer I would use that. You would need the help of someone who can feel contact with the table and maintain it .Joint one pc with the face side to the fence and the other with the face side out.
A slight hollow in the middle would be good,over 17 feet that could be 1/8 inch .Do not allow either end to be open.On things that wide I have ,at times ,improvised a tall plywood fence for wide lumber.

[lowell holmes]

You might want to check with Pat Warner about that. He is sure to have an opinion. I think he is a member of this group.

I think you are flirting with a problem. I don't believe that router bits are engineered to with stand the forces and shocks that will be created.

I would make an eighteen foot straight jig from a sheet of plywood, with a raised edge for my PC 7 1/4" saw to ride against. I would edge each board individually and fit them together with a hand plane if necessary.

[keith micinski]

Im not the best with a hand plane jointing because I have only tried it a few times but that really is the best way to do it. Cut it as close as you can with a saw and guide and then tune it up with the plane. I think this is one of the areas where hand tools may actually be better then there power equivalent. A straight line rip saw would give you the best start but I bet it would still need tuning up over a 17 foot span with a hand plane.

[Harry Hagan]

I’ve done this quite a few times and a sharp saw blade that leaves a smooth cut suitable for joining edges is the way to go. The key to success is keeping the saw edge tight against the straight edge at all times. Any deviation will most likely require you to repeat the cut.



One continuous edge is essential. It doesn’t have to be perfectly straight since both sides of the blade cut a different board and will yield a perfect match if the edge and the boards don’t move and the blade fully cuts both boards. You’ll probably need to make several cuts to get the second board close enough for the final cut.
Use an alignment aid like biscuits, dominos, etc. to ensure the top surface is level when gluing.

[Steve Rozmiarek]

thanks steve, yes I'd rather have the stability of a saw in the plan. I was so worried that it has to be $$ plunge saw that I thought maybe using the right router bit would be stable. good blade on my milwaulkee circular saw? don't know. a nearby shop has a straight line rip saw, again, would the edges be good enough?

Your milwaukee circular is were I'd start. I don't know on the straight line rip at the other shop. Seems to me that sometimes I get straight line ripped stock that is not straight. I imagine that those machines are as good as their operators. Honestly, you can squeeze a little wiggle out on that long of a board with clamps, as long as it's gradual, like what Mel suggested.

[David Bowen]

I'm leaning back to the plunge saws with guides. Maybe I should just try my old milwalkee circular saw with a plywood guide and good blade, hand planing, hummm, electric planer? If it needs more guidance, get out the checkbook for a plunge saw and guide....

[Sam Murdoch]

David your router concept seems unworkable, especially considering the thickness and species. Running 2 sides at the same time is way too much to ask - at least with any 3 HP router and/or any kind of bit I have ever used.

Knowing that you have a shop nearby with straight line rip capacity I might consider gluing up a sacrifice 18' double thickness of pine boards from which this shop could produce your straight edge. I would double up 3/4" stock so that you could get good overlay on the joints - unless of course you have a source for 20' soft wood boards. I would then use the new straight edge as my guide for a good circular saw - a new blade for each rip.

You might consider gluing a strip of masonite to the edge of the straight edge to guarantee a hard surface to glide against but I think that would not be necessary. Rip each oak board individually with a steady comfortable feed rate. Might be a good idea to have another plywood fence opposite the primary straight edge to keep you tracking properly. Ideally your oak boards will be fully supported but left open under the cut to allow at least some relief for the blade. Another important aspect will be that your support system is very flat. You will achieve the best results with flat as well as straight. One helps to guarantee the other. Sand and plane if need be to achieve a final good joint.

As an aside - rather than using a chalk line or string I would use a laser as my guide for laying down the straight edge - though this should take care of itself if you have a good 18' straight edge to begin with. Good luck with this project. Big yikes factor on this one :eek:. Have fun. Show photos.

[Steve Rozmiarek]

I'm leaning back to the plunge saws with guides. Maybe I should just try my old milwalkee circular saw with a plywood guide and good blade, hand planing, hummm, electric planer? If it needs more guidance, get out the checkbook for a plunge saw and guide....

It would be a reason to get a nice Festool saw setup....

[Mel Fulks]

Some of the replies here would definitely not be used in a commercial shop,that is not to say they would not work. If the op had the skill to hand plane I don't think he would be contemplating using the router. Using a jointer requires some skill ,but he has a better chance of finding someone with that skill than than someone to hand plane it. Jointing by machine might require some table adjustment and that it delicate ,but doable.Any fit between a small opening in the middle and one toward an 1/8 should be accepted. NOT any opening at the ends.

[Mel Fulks]

In regard to using a straight line saw,some of those actually have a feature that allows you to intentionally set them to make hollow glue joints.I have not used one with that (that I am aware of),but I googled them recently and saw it.

[Jim Becker]

The router method is absolutely viable...and safe. The trick is to 1) arrange the two boards so that you are taking minimal material...the 1/8" mentioned is reasonable for that...and with an edge guide of some sort and 2) only route a relatively shallow cut...maybe 3/8" to 1/2"...which you can then use for a guide surface to finish the rest of the "cut" on each piece independently using a bit with a bearing as in pattern routing. The initial cut is no different than making a routed slot for inlay work. The same method can be used with a circular saw for the initial shallow cut (boards obviously closer together) and then using a bearing to flush the rest of the surface with a router on each piece. I would do this in a second over trying to balance a big board like that on any kind of jointer, even with help. If the two boards are properly and securely supported for that initial pass with the router or saw, you will end up with a great mirror edge for glue-up.

[scott vroom]

In our 2 man shop we straight line ripped and then edge jointed four 14' x 7" 5/4 QSWO planks for a desktop. We used a Grizzly G0490X 8" jointer (76" table) supplemented with infeed and outfeed roller stands. Worked flawlessly.

If you don't have big equipment you might consider taking your planks to a local commercial cabinet shop where they can straight line/edge joint and (if necessary) plane to your specifications, for a reasonable fee.

Tackling this alone with hand held equipment, unless you're experienced, might end up costing more in the long run.

[Peter Quinn]

A good straight line rip saw with a glue line blade would give an edge sufficient for successful gluing. I've literally done hundreds of them in ash 15-17'. We usually make a first pass to straighten one edge, rip the second edge off a fence to get parallel, then re rip the glue edge to get it straight enough for glue. You don't want to be taking a lot off on at last pass, just a kiss. But you don't have to run out and find a shop to do it. The longest jointer I have used was over 9' and it won't put a staight edge on a 17' board, though you might get close enought to glue up with enough passes. The geometry is not in your favor on at length with a jointer IME. I've cut 20' dead straight with a cheap makita skill saw and a quick shop made guide. Two 8' rips of 1/2" MDF butted against a 3rd straight rip, biscuit them together, add a 4' piece to one end, attach a guide fence to one edge, make the base a bit wider than the offset of your saw, the first rip through the base gives you the guide edge, that's where your cut line will fall on the actual work, so it's easy to allign. A decent Freud diablo blade will make a fine cut, might take a second lite pass, might not. At work I would use a large machine and several guys to make short work of it, at home I'd make a saw guide. Of course the real tricky part comes AFTER you join these things into one huge top, so you may want to form a relationship with a shop that has a wide belt now, or forge a closer connection to those hand planes.:D

[Mel Fulks]

Scott,I certainly don't doubt your experience but I have never been able to get the stands set exactly right.Fortunately there is always at least one guy to help who can keep the work on the out feed . It is one of those things that some can do easily and that some just cant learn. Unless the material is longer than 14 feet ,I can usually do them by myself on the old large mill jointers ,and prefer to do so.

[Richard Coers]

I'd take a whole different approach. I would propose an artsy approach to the table design that spaces the two boards apart from each other. A walnut spline, below the surface, that keeps the white oak spread apart, and walnut bow ties tying the two slabs together. Or a gap with bow ties tying them together. Lets them bring up communication cables as an extra bonus. Something like that will also help with problems with the flattening of the entire boards. How are you making them flat? 20" wide, 17' long means they are likely just going through a thickness planer. Sure hope it was something like a strat-o-planer so one face was flattened before facing the other side. That's going to be a massive pain in the @ss job. From start to delivery. 5'x12' was the biggest I did. Hated that job, but ordered a custom laid up top and built it into a torsion box. Personally, I would have let your job go to the specialists. How many bases, or legs are you putting on that thing? Just can't get my head around the job. I bet the cost of a track saw should have been small potatoes to the overall cost of what the bid should have been. How you going to keep a wet edge when spraying something that is 40" x 17'? Then rub that out? OY VEY!!!!!!!!!!! Good luck!

[David Wong]

The late John Lucas featured a pictorial on edge jointing two boards with a Festool saw. Here is a link to the article on his legacy.woodshopdemos (http://legacy.woodshopdemos.com/fes-53.htm) site.

[scott vroom]

Scott,I certainly don't doubt your experience but I have never been able to get the stands set exactly right.Fortunately there is always at least one guy to help who can keep the work on the out feed . It is one of those things that some can do easily and that some just cant learn. Unless the material is longer than 14 feet ,I can usually do them by myself on the old large mill jointers ,and prefer to do so.

It does require some care in setting up the roller stands. Our stands are adjustable on all 4 legs and with a straight edge it's not too difficult to set them level with the infeed/outfeed tables. It also helps to have one person standing on the outfeed side applying constant down pressure on the stock.

There are many ways to skin this cat...as evidenced by the many good suggestions from other posters.

[keith micinski]

I have never tried to joint 17' long boards on a jointer but doing ten footers is hard enough,the last thing I would try with stock this big is to try and joint it on a jointer of any size. It can obviously be done but seems like the wrong approach. The biggest heaviest most unwieldy part of this project is the wood so would definitely try and take the tool to the material in this case. I would also stay away from the router. Again it will work but its not what a router was designed to do and it's just to darn easy to have a router get off course. Setting up a good straight line and using a good circular saw blade will leave you with a really close edge. Then having to touch it up with a hand planer here and there is no big deal.

[Wade Lippman]

Unless you can find an enormous jointer, or can develop some real skill with plane, I think your idea is the best.
Obviously you have to get them pretty straight before hand, and position them so you are only taking a few thousanths off both sides, and keep them from moving; but if you can do all that...
I don't think you can get wood that heavy to close any kind of gap when clamping; you have to be perfect.

[John C Bush]

I made a 48" X 10' harvest table using 3- 3" cedar slabs and had the same dilemma. I made a straightedge of scrap ply, used a top bearing guide rabbiting bit set deep enough to create a guide surface on both edges for a longer top bearing flushcut bit, then made enough passes to get a good joint. The first referencing cut is just like making a dadoe and IIRC I just needed two more passes to finish the edges. I used biscuits for alignment and got a great result. Good luck. JCB.

[John C Bush]

I have done it like Richard Coers suggested as well. I have made several natural edge slab tables with joints that follow the curve of the grain or other appealing features of the slabs. Some were tight joints and others were bow tied across splits or major trunk furcations. Some we filled with epoxy with the natural edge features showing thru and others we left open. We did learn that you need to mix the epoxy accurately or it will be less translucent and not show the goodies beneath.

[Mark Wooden]

As Mel said, first choice would be a jointer with a good helper.
But I’ve had to make more than a few “in the field” joints for a glue up when a jointer was just not available.
Put the two edges to be joined together and clamp them in place on a few sets of saw horses. Set your straight edge so your skill saw blade travels down the middle of the joint; rip the pieces and put the two edges tight together again, re-clamp and re cut . Repeat until you have a glue-able joint. The key is to cut both edges to be joined at the same time, ending up with just a saw kerf between them. Doesn’t even have to be straight as you’re match cutting the joint. Use a decent, new blade to do it.
You can do this on a tablesaw also, but you have to screw 2x cleats across the planks to hold them in place and the straight edge goes to the fence

[David Bowen]

I like these suggestions. Thanks Steve

[David Bowen]

I've done that with narrower boards. Had limited success. These boards are 20" wide though!
thanks

[David Bowen]

Sounds good

[David Bowen]

I've done that with narrower boards. Had limited success. These boards are 20" wide though!
thanks

[Sam Murdoch]

If my calculations are correct, I'm figuring that each one of these boards weighs in at approximately 175 lbs. +/- moisture content.
Bring the tool to the wood.

[Mel Fulks]

My comment that some of these ideas would not be used in a commercial shop was not a rebuke .But the idea that this can not be done with a jointer ,when some of us have done similar jobs with one,is wrong. The width of the boards is the
most unusual thing here,not the length .They are heavy ,but nothing two guys can't handle. It is not necessary for the
material to be perfectly straight, the range I have suggested would work fine and is a standard long used and advocated.
Some don't want to use sprung joints ,that's fine. But the fact can easily be checked that machines are sold for that
purpose and straight line saws with that feature are not cheap gimmicks for guys who don't own routers.They are expensive precision machines for production shops. The op knows what he can afford,there is no reason to give inaccurate
information,it could only serve to limit his options. If real options are known he can choose to sub part of it. The boards
should be carefully faced and planed before the gluing,and if practical in this case left a little thicker than they will finish.
As said earlier there are a number of ways .

[Todd Burch]

I think I would opt for elongated in-feed/out-feed tables: 1 sheet of ply (or better, MDF), cut into four ~12" strips, (2 on each side of the jointer, so that's 16' each side, held up with 1X4 legs.

Or, an array of begged, borrowed or stolen roller stands, tied together for stability.

Then, a long rope wrapped around the far end so that helper #1 (on out-feed side) could pull the board, helper #2 (tail end of the board) could stabilize the boards, and you would be at the middle for additional stabilization and observation, watching for the clean cut, making sure the board is up tight against the fence.

I'm thinking for a conference table of this size and caliber (2 wide plank boards of this length), you certainly should have factored in some "jigging" costs. $75 worth of ply and 1X4s, plus some wax, would do it.

Todd

[Peter Quinn]

Ok..on the jointer thing, is everyone clear the op stated 6/4X20"X17'. Too thin to flatten generally over that distance unless its already pretty much flat to begin with, or he wants a 1/2" thick table top. I've long since lost count of how many ridiculous long/wide/thick boards I've been required to make sense of at this point, its part of my job on a pretty regular basis. And I'd argue till I'm purple, that there are simply limits to what even a large patter makers jointer can accomplish no matter how many people you involve. If the machine is 10' long, and thats a generous table, that gives you maybe a bit over 5' of infeed, which leaves a good 12' not on the table going in to the cutter head. If you you start with a slight smily face, add in a bit of wind, a touch of rough on the B face, figure that at 20" at least more than half the stock is above the fence....well the thing is just bobbing and weaving across the table. I'm not making this up, we've actually tried it. You take a few passes, site it, not much straighter, take a few more, realize the stock is so much longer than the machine that you are "sneaking up" on straight without ever actually getting there because the reference table is too small a percentage of the total length. Its like a parabola that approaches a line toward infinity but never intersects. It may work if you straighten the edge by other means so its pretty close, then make a finish pass over the jointer, assuming the boards are pretty flat and smooth, but if not that can actually make things worse in some instances.

If you told me you had to straighten 10K BF of lumber, I'd suggest a straight line rip saw. For two boards? A chalk line, jig saw and a decent jointer plane is a cheaper way to go.:)

Just read Todd's post, if he has 16' of MDF infeed support, he needs a 16' straight edge to make sure its flat, might as well use the straight edge with a router and save his back!

[Prashun Patel]

I would use a circular saw.
but do it upside down since the clean side of the cut will be on the bottom.

you could also clampthe pieces bookmatched and then rip clean the edge. This will require only one straight ege and wont require the saw to be captive. However, its a deeper cut. The nice thing about ripping bookmatched is that you can coean up the cut with a plane while the boards are still clamped.

tell me how it goes. I am about to begin a 9 foot dining table which has to be joined similarly.

the question i have is how are you flattening those boards prior to glue up?

[Don Stephan]

My first suggestion would be a good quality jointer plane.

My 2nd suggestion would be pattern routing, and I'm trying to remember how the process was described in Dining Tables by Kim Carleton Graves. An 18-19' template could be used to pattern rout the right edge of the left hand board. The just routed edge then would be used to pattern rout the left edge of the right hand board. This assumes that the ssurfaces of the two boards are flat.

[Thomas Hotchkin]

David
There is an article in FWW magazine from winter of 1977 number 9, about using a router to edge joint boards. John Harra wrote the article and said that he has routed up to 3" deep material with his system. He does not mention the length If you want to read the article can't get a copy send me a PM. Tom

[Jim Andrew]

I have set up a router to fit 2 pieces of laminate together, to make the tightest seam possible. And it works well.