jointing and gluing tabletops - need help improving my results!

[wdthompson]

For starters, I am a beginner woodworker, just trying to learn a few of the tricks of the trade. I have made a couple of coffee tables recently, both out of cherry. The first was intended to be a very large, beefy and rustic table, with a live edge. The top is roughly

36" x 60" and about an inch and a half thick. Legs all 1 and 3/4" square, rounded edges 3/4 of the way up and some beadwork on the aprons. The wood was dry and all quartersawn. Nevertheless, I had a very tough challenge trying to joint those boards due to their size. The table came out great though and I've had very little movement on the top (glued and biscuited). I finished with some Poly and wetsanded and polished with rottenstone for a really nice finish.

The second table however, just a bit different. This one was fashioned out of 1" thick cherry, mostly flatsawn. (Same legs, aprons but a nice oiled finish.) I made a much smaller table and the top is say 32"x 48". I tried to carefully joint the 3 boards I used for the top, used biscuits again and a good glue- clamped flat. I have now noticed two of the joints opening up just a bit- which is causing me a bit of concern.

My longwinded question- what can I do to improve my gluing results? I bought a large cherry dining table, 8' long 4' wide that has 6 1" boards glued together without a trace of imperfection anywhere. I want results like that!

I really appreciate any pointers, links or other suggestions. Also, how can I correct any spitting that might occur? Could I use some type of screw from under the table top (maybe in a pocket jig hole) to draw the boards back together? Other techniques to correct.

Thanks much

PS- I do recognize the importance of seasoning the wood, and the issues that cause wood movement- what I am interested in other techniques to improve the success rate and also how to correct the splits after the fact!

[C & S]

. I have now

Did you have to pull them together to glue the joint? that's a no no. They should be really really straight before glue-up.

The easy way is to start with dry acclimated stock and pass it over a well-tuned jointer. The other way requires skill that I don't have so I will save that for someone else.

Remove the top and rip through the seam on the table saw. Rejoint and reglue. You want to remove the stresses pulling on that joint.

Movement is fine... what is getting you here is unequal movement.

Regards,

Steve

[alexM]

Assuming boards were jointed well (on a well-tuned jointer with sharp knives using good technique) try jointing boards twice. After the first jointing let the boards sit for a couple of weeks to "settle down". Then joint again and glue. Some say after jointing on a jointer, you must use a jointer plane to get perfect glue edge. Don't have #7, wouldn't know.

If your first table was made out of a softer wood than cherry, imperfect edge was smashed a bit by clamps and the glue line looks fine. That'll be my guess.

alexM

[wdthompson]

Thanks. I probably didn't explain accurately. I didn't "over clamp" the boards, nor have to "pull" them together. I have a minor split on one end of the table, along the seam. My jointer is new, but I'm just as new in using it. The boards all looked tight prior to gluing, and they stayed tight for several weeks before the split started to show. I just want to find out how I can assure the boards are perfectly flat along the whole lengths and perfectly parallel to one another along with any other tips that help assure success.

On this particular project, unless the seam really opens up a lot more I can probably live with it. I really don't want to re-cut and glue it again unless it really opens up and becomes very noticeable.

[Swingman]

Often it is the sum of all the little things you do that lead to sucess in glueups.

If you don't already do it, use the principle of "complementary angles", along with your jointer, for just one more little piece of the puzzle to help get closer to "perfect enough" glueups.

With all boards faceup, as they will be in the final glueup, put an "I" on one side, and an "O" on the opposite side of each adjacent glue joint with a piece of chalk/pencil.

Then do one more pass over the jointer as follows:

"I" (inside) means that face goes against the jointer fence.

"O" (outside) means that face goes away from the jointer fence.

Make a pass with each marked edge in the appropriate orientation as above. Interior boards will get two passes, the two end boards will get one each.

The resulting edges of adjacent boards will now equal 90 degrees even if your jointer fence is not precisely set to 90 degrees.

This method will help you take advantage of the principle of "complementary angles" to obtain 90 degree joints for adjacent boards in a glueup, without getting mixed up, and will speed the process tremendously.

If you can get the advice of letting freshly jointed boards "sit for a couple of weeks" before gluing up, you're a better man than me.

Personally, I prefer to glueup immediately upon edge jointing ... I've had much better luck that way, time after time.

YMMV ...

[nailshooter41]

along with your jointer, for just >one more little piece of the puzzle to help get closer >to "perfect enough" glueups.

SNIP of excellent advice.

I had to laugh when I read that, not at you, but thinking of myself in the shop. I can be such a distracted idiot sometimes when working, I can't use anything as sophisticated as two marks... it is no use... beyond me.

I lay the boards out the way they will be glued up, with an X to signify "up" on the side I am standing on. I pick up one board, walk over to the machine and square off one edge. I walk that piece back over to the layout and put it where it belongs. The interior boards are jointed by making sure that I start on the same end and mind my technique. If one is a little off, I flip it around and joint with the other side facing the fence. They all fit with a pass or two. I spent an awful lot of time setting up my jointer with a machinist's square to make that happen.

I never thought of doing them all that way on purpose!

Damn! You're taking all the fun out of it!

couple of weeks" before gluing up, you're >a better man than me.

much better luck that way, time after >time.

Me too. I have bought so much improperly dried wood lately that I plane/joint/glue as close to the same day as possible so I can keep a handle on the movement. Better yet, apply finish as soon as possible to help keep the wood from drying unevenly. No matter how good the finish is, the wood will continue to outgas and dry, just at a significantly slower rate once finished, but the movement will be greatly reduced.

Robert

[wdthompson]

Thanks for the great tip. I use a square to check the jointer's squareness, but this sounds like an excellent method to employ and I will try it on my next project.

Thanks again!

[Lew Hodgett]

Now that is just plain damn sneaky.

Mikey likes it, so do I.

Lew

[Drew Lawson]

I get it, but only because it was in one of the woodworking books I read.

The principle is that wood grows under tension, and when it is cut the tension is (to some extent) released. The less you are changing the board, the less the effect will be from that release. The larger the change (ripping a wide/thick board), the more chance that there will be shifting as the wood fibers get their freedom back.

It makes perfect book sense to me, but I don't have the experience to say how drastic the effect is in real life. I assume it is more pronounced in some species than in others.

[Bill in Detroit]

[e-mail] wrote: I

I made a Stoutman gage to get my 90. Makes it easier to get BACK to 90 after I reset the width. Zero the gage to the square. Zero the face to the gage. Done.

Bill

[Stoutman]

Would you believe that Fine Wood Working Magazine rejected this tool for their "Methods of Work"? I submitted it, but they gave me the finger.

It makes me laugh because I thought it was a VERY usefull idea. Yet new gadgets for shop made paper weights will get accepted! Go figure.

[alexM]

Not sure what's so hard to rough mill before the final milling. I rarely skip it, especially for joints like M&T. Saves me from troubles I don't need.

[Bill in Detroit]

Yabbut, mine has brass wear pads, three kinds of exotic hardwoods including a jatoba base and a totally gratuitous blind dovetail. ;-)

Be careful of that finger .... there's no way of knowing where it's been.

;-)

Bill

[Stoutman]

This I gotta see. Can you post pictures? :)

[Stoutman]

Yep. I took to much grief over the bent nail. ;)

[Stoutman]

Yes, but I haven't gotten around to doing it yet.

That I haven't thought of. Good suggestion!

[Bill in Detroit]

Well, since you insist ;-)

[Stoutman]

Wow! That's cool Just a little nicer than my bent nails. :)

[Peter Huebner]

I simply won't use any boards wider than 5" any more. You can get lucky with wider boards, but don't count on it.

The most effective way of preventing splitting after glue up is to finish the whole thing with a film that slows moisture way down - like, say, several coats of polyurethane. If the endgrain cannot absorb or lose moisture rapidly, you will not have those splitting problems and also no buckling due to the top side losing moisture more quickly than the bottom side (sunlight, warmth).

If you want to use oil finishes etc you have to get the timber much dry-er in the first place, in my experience. Again, much can be done by soaking and soaking the endgrain with the oil to slow down moisture travel.

h.t.h. -Peter

[Bill in Detroit]

Thanks Stoutman ... one of those days when I wanted to be in the shop but couldn't remember why. So I decided to just play around.

When you first posted about your gauge, I'm probably the guy who ragged you about the nails. I'm glad to see that your new and revised version has overcome that obstacle on the "Stoutman MKII" ;-)

I'm still a machinist at heart ... it's just how I was trained and how I perceive things. So it can be a real challenge to work in a wood shop where nothing stays put and controls are missing off the equipment. (Okay, if a bandsaw is all that and a bag of peanuts, where the heck is the dial to set the width of cut? Why doesn't the blade guide set itself about .010" above the work? And why doesn't my table saw know how high the stinking blade is? I should be able to 'zero it' and work all day off that single setting.)

;-)

That should bee enough for two or three 'muse' threads.

Bill