Need advice joining wide boards

[F Seaman Unique Woodcuts]

Fellas
I need some advice. I need to join narrower slabs to make tabletops. I am having trouble getting two edges true enough to clamp and glue.









These will be 12in to 24in or so wide, 8/4 to 10/4 thick, and up to 16 ft long. Obviously I cannot run these across my joiner, too long and heavy.
So I have a couple of ideas to get an edge good enough to glue, and would like input from those of you with gluing
experience.

Idea #1 Festool 75 circular saw with guide, if anyone has one, I would love to bring a couple of slabs for a demonstration. I cannot buy one without knowing it will do what I need.

Idea#2 1/2 in arbor router ( and straight edge guide) with straight bit to clean up on uglier cut with my current skill saw. I think a smaller arbor bit would flex???

I plan to glue up these tops then plane and sand on my Lucas mill.

These are the two options I have come up with, and I am not even sure if either will work.

I am sure the right idea is somewhere in this forum base of knowledge.
Thanks so much.

Frank

 

[jazzflute]

Is your design set in stone? The reason I ask is because I think you are going to have even more of a challenge clamping the two pieces together tightly enough across the span you are talking about, especially with a live edge on each side. You often see slab tables with a slight gap between the two slabs, or joined together with butterflies. This also helps compensate for some of the strange expansion forces that can act upon large and thick slabs.

With that said, I think a tracksaw may do what you want, but the tops will have to be level first so that the track can sit level on the surface. The router would be tough, given the thickness of the slabs and the number of passes you would have to make to work all the way through.

K

 

[redknife]

I have a festool 75 you could try on a slab but I'm probably located too far away. That's what I would use. Chris

 

[Jeremy Scuteri]

The TS 75 track saw should do the trick. The max cutting depth is 2.75" when using the track. That will make it through 10/4, but it won't cut deep enough for 12/4. One thing to keep in mind is that Festool products have a 30 day money back guarantee. If you got it and weren't happy with the result, you could just return it for a full refund. The biggest issue I see here is the 16' length. You can gang multiple tracks together, but that will get expensive pretty quickly.

The router bit method should work as well. I agree that a 1/2 shank is a good idea with a bit that has a 2.5" cutting length. I would think the toughest part here would be creating a 16' long guide that is straight enough for a glue joint. Maybe you could rig something up that would allow you to cut both pieces at the same time (very light cut on both sides), then any error in your guide would be cancelled out. I saw this on a woodworking dvd before, but the guy wasn't doing it on slabs like you have. Setting something like that up is probably easier said than done.

A possible 3rd option would be to clean up your circular saw cut with a hand plane (jointer plane). Holding the work in an upright position may pose a challenge.

Good luck and keep us posted on what you end up doing.

 

[blakeyon2asd]

I don't know if I'm reading this wrong but from what I understand you are trying to join super thick boards and the joints you are getting aren't tight enough to make a good for good glue ups. If that is what you mean I would take all of the pieces at one end and use a good square and try to get it a perfect square drawn on the end. Then use a heavy hand plan and go over all of the sides until all sides are in line with the square you come up with on the end. Then take a square go down the full length of the board and make fine adjustments with the square. Then repeat this process with the rest of the boards that need to be jointed. After you have them ready for the glue up make sure you have some very fine saw dust from the wood so that it matches. Glue it up remove all the extra glue then make a jig to go on both sides of the glued up table top and use a router with a flat piece of wood to set on the two boards on the outside of table top and use the router to flatten the top out and then flip and repeat. Then use the hand plane to finish it up.

 

[blakeyon2asd]

I don't know if I'm reading this wrong but from what I understand you are trying to join super thick boards and the joints you are getting aren't tight enough to make a good for good glue ups. If that is what you mean I would take all of the pieces at one end and use a good square and try to get it a perfect square drawn on the end. Then use a heavy hand plan and go over all of the sides until all sides are in line with the square you come up with on the end. Then take a square go down the full length of the board and make fine adjustments with the square. Then repeat this process with the rest of the boards that need to be jointed. After you have them ready for the glue up make sure you have some very fine saw dust from the wood so that it matches. Glue it up remove all the extra glue then make a jig to go on both sides of the glued up table top and use a router with a flat piece of wood to set on the two boards on the outside of table top and use the router to flatten the top out and then flip and repeat. Then use the hand plane to finish it up.

As far as cutting the boards to get them to line up the track saw would work if you could find some boards long enough you could use something like the jig I posted last night on the forums to make a perfectly straight cut on the boards and you wouldn't have to spend the money on a festool track saw. As long as you circular saw would make the cut which it should be able to if you were to cut half way through one side then flip the board and finish it with the other side the hit it with the hand plane to flatten it up enough for gluing.

 

[jazzflute]

You could also find someone with a sliding table saw. Most of those are limited to around a 10 ft. cut length, but you would definitely get a straight enough edge with that.

K

 

[Mark Gottesman]

If you are going to be handling irregular pieces of wood that size I would look to methods used by either boatbuilders or timberframers. I If I had to get a glue ready edge for a 2.5" board 16 ft long I would see if I couldn't find a beam Planer (Large handheld planer) and make up some sort of guide rail to get a straight cut. Couple of tall doors should work. Or set up a pit saw. How about one of those chainsaw mills that runs on a 2x4 guide?

If you need to pull the pieces together think about gluing blocks to the surface to grab with the clamps. good Luck. sounds like a job for Paul Bunyon and Babe.

 

[Steve_Honeycutt]

Here is my idea. Screw a straight edge to one side of the slab and run the straight edge against the fence on the table saw. Even 1/4" plywood would work if the plywood were on the top of the slab as it goes through the table saw. My contractor saw will cut up to 27" wide. You may have to have some help handling a 16" slab.

Steve H.

 

[Mike Davis]

3 inch angle iron 20 feet long for edge guide.

Rough cut with any 8 inch circular saw.

Router with 1/2 x 3 inch straight cut bit.

joint one slab with router, slide second slab up against first without moving guide, route second slab.

any curve in the guide will be matched on both slabs.

The hard part will be building a table 5 feet wide and 20 feet long that is perfectly flat.

 

[Rick M]

I don't know that I would edge glue them but leave as separate pieces joined with butterflies

Sent from my T-Mobile G2 using Tapatalk 2

 

[chris_goris]

Circular saw and a hand plane?

 

[Endless Pursuit]

Since it sounds like you will be making multiple table tops, I would start by building a fixture to run a plunge router over. 2 - 2X12X16' in SYP standing on edge. The straighter you can find them the better. Clamp them together and hand plane them so that 2 edges are straight and flat. 1 is now you right "rail" and the other your left rail. At each end, screw a 6-7" spacer between the rails keeping the hand-planed surfaces level and flush. The rails don't have to remain parallel, a bow or curve won't affect their function but they must be as flat and level as you can get them.

Build a simple flat sled for a plunge router say, 6" wide X 18" long X 1" thick. Drill a 1-1/2" hole at the centroid for a 1" flat bottom box bit to fit thru. The flatness of this board will affect the final cuts on the edges of your slabs more than any other factor. DEAD flat and uniform thickness us called for. Attach the router to the top side of this board (sled) with the bit protruding just below the underside of the sled.

Use a chalk line and Skil saw to create your crude slab edges. Place the two rough cut edges up with what will be the top sides facing inward. Clamp them together robustly at each end keeping the top clamp a bit below your desired finished edge.

Prop your huge slab sandwich vertically and securely. Place the rail assembly down over the top crude edges of the slabs and support it so that the top edge of the rails is say 1/4-3/8" above the rough cut edges and secure the rail assembly in place such that it will support the small force of sliding the router sled along it's length. Start at one end and take light cuts moving the router to and fro across the parallel rails till you reach the opposite end. Repeat with a progressively deeper plunge setting until you have removed all the saw marks leaving the edge of each slab flat, straight and mirror images of each other. Remove the fixture, clamps and with 12 of your timber framer friends, "unfold" the two slabs and join what should be 2 identical edges. Share a case of beer with your fellow timber framers.

 

[blakeyon2asd]

This is getting really complex am I missing something? All he needs is flat edges to join right? If cutting it with a saw and hand planing it flat can't handle it can it actually be done with a router? I understand what Mike Davis said. But unless he making a good deal of money from these tables buying a bunch of tools just to be able to joint them together seems unreasonable when there are cheaper easier solutions.

 

[Endless Pursuit]

This is getting really complex am I missing something? All he needs is flat edges to join right? If cutting it with a saw and hand planing it flat can't handle it can it actually be done with a router? I understand what Mike Davis said. But unless he making a good deal of money from these tables buying a bunch of tools just to be able to joint them together seems unreasonable when there are cheaper easier solutions.

He owns a portable sawmill ( Lucas mill) so the thinking is he will be doing a lot of these and buying tools doesn't seem to be an issue. We're just giving him a good reason to spend more money on equipment!

 

[blakeyon2asd]

He owns a portable sawmill ( Lucas mill) so the thinking is he will be doing a lot of these and buying tools doesn't seem to be an issue. We're just giving him a good reason to spend more money on equipment!

So he owns a portable saw mill. Well why doesn't he run them through and clean them up with a hand plane lol that would be super easy. Even if he does have the money to buy the equipment that would be way more logical. By the way I'm not trying to be out of the way my thought process is if I can do something without spending money unnecessarily that's more money to put back on something better. I guess I'm a tight wad but I like to keep cost down for myself and the customer so everyone's happy at the end of the day.

 

[Bob Carreiro]

+1 for Mark & Jeff... build a sled for either a router or hand-held power planer. Either should work just fine.

I recently helped my nephew in upper State NY build a sled to take a 16/4 slab, 10' L, 20" Wide down to thickness using a PC 690 Router with a 3/4" dato bit (biggest he had). It took a while, but came out OK after a little sanding with an ROS.

In your case, build a longer sled (using angle iron would work best, but not required) for a router using a larger bit - 1-1/2" or greater - to make quick work of the edge(s). You can also use 2X material for the runners, but you'd have to edge them on a jointer first - a not impossible feat. Good luck and let us know how it came out!

 

[Gotcha6]

If he's looking to buy a new tool. the Makita 16" circular saw should do the trick.
http://www.amazon.com/Makita-5402NA...f=sr_1_10?s=hi&ie=UTF8&qid=1392552768&sr=1-10
I'd go with either butterflies or blind draw bolts like used on post formed laminate tops from below. Butterflies would be the proper way by tradition. The problem with gluing up these slabs is twofold:
1. Are they dry?
2. With the grain slope they have they are likely to move again at a non uniform rate even if they are. When they do they will delaminate.
Splining would help on alignment.

 

[Skymaster]

look for a wood processor with a straight line rip saw, let him plop em in laser line em up and run two straight egdes ZIP, lightly plane em a tad smoother and wally!, glue em,clamp em, butterfly em. Have a coffacuppy

 

[Bill Clemmons]

Frank, it sounds like what you are trying is along the lines of George Nakashima's incredible slab tables. I can't help w/ HOW to do it, but I can give you a link to images of his work that may give you some ideas.