Table top advice needed

[Naildrivingman]

I need guidance on building a dropleaf tabletop.  My first attempt didn't go well.

The basics are:
Long side 42"
Short side 24"
Drop leaves 9" each

The First Process
I built the first top from a picture and desired dims.  The picture I was given shows the individual boards running the short way.  All boards were planed to 3/4"from live edge #2 rustic hickory and ripped to nominal width of 2 1/2" - 3".  I used 5 dominos (8x40) per joint (2, 7, 12, 17, 22").  I clamped using 3/4" pipe clamps in an alternating pattern (3 on bottom and 2 on top).  The top was significantly warped +/- 1/16" and the joints were not aligned in all spots.

Proposed Second Attempt (
Same dims, but with boards running the long dim (same thickness and width)
Increase dominos to nominal 4" O.C.
Same clamping method with more clamps

Feel free to correct or augment any of my proposed 2nd attempt techniques. Additionally, I would like to create the drop leaf mechanism from hickory and avoid modern hardware (hinges exempt of course).  I am not opposed to modern drop leaf hardware if I cannot easily be seen.  Any suggestions of this mechanism with pictures/links appreciated.

I think that's it.

Thanks!
Chris

 

[deepcreek]

I don't think the spacing of the dominoes needs to be decreased nor the number of clamps increased.

Running the boards in the long dimension will improve the chances of a flat glue up.

When you say "warped", I wonder if it came afterwards due to moisture changes in the wood.http://www.lonniebird.com/wood-moisture-content-by-lonnie-bird/

To get a dead flat panel glue up, I would strongly recommend using clamping cauls. http://www.finewoodworking.com/2011/03/08/clamping-cauls-the-secret-to-great-glue-ups

I don't want to diss bar clamps but having used both I prefer parallel clamps (like Bessey K-Bodies) for this type of glue up.

Good luck!

 

[Naildrivingman]

Thanks Joe,
I think the use of cauls will make a significant difference. I'm wondering if angle steel would work.  without buying more clamps, about all I have that will work would be C clamps.  that brings me to why I have pipe clamps.  I have used the Bessey clamps and they are very nice, but for the frequency that I use clamps I couldn't justify the expense.

As to the warping, I think the cause was a combination of the boards running the short dimension, no cauls and too much clamp pressure.

Do you have any suggestions on the hold open mechanism of the drop leaf?  As I mentioned above, I would like to stay old school if I could.

Thanks,
Chris

 

[deepcreek]

Chris,

I think you'll have much better results the second time around.

I've never made a drop leaf so I can offer any help on the mechanism.  If you don't find what you need here, you might try seeking suggestions on another woodworking forum like Sawmill Creek or Woodnet.

When you get done, please post photos to show off your work.

 

[Cheese]

Why not just make some clamping cauls. There are patterns floating around the internet on them. It's a pretty straight forward task and you'll be able to use your C-clamps. You just need some wood and a jig saw.

An alternative, is to dial up Woodpeckers, as they'll fab cauls from phenolic. I have several of them and they're great.

 

[Stone Message]

Hi Chris

In order to reduce the effect of wood movement (that causes the tops to warp) try and alternate the grain of the boards before joining them. If you look at the end grain you will see how the grain runs (might be bottom left to top right, top left to bottom right, a open curve upwards or an open curve downwards).

Do not get to fixated about the number of dominos. I would think that no more than 4 along each length would easily be enough. When I break down really old furniture in order to salvage the wood I rarely see floating tenons between the boards, it is usually just glue alone. That said, I would use a few dominos to help with alignment.

Do not put a silly amount of pressure on whilst clamping. The pressure should be enough to bring things together but not enough to force all of the glue away from between the boards.

When clamping, alternate the clamps so that one is fitted from one side and the next from the other. That way any cupping cause by clamping will be eliminated.

I have said all of this on the assumption that your wood is dry or its moisture matches the destination location for the finished piece.

Good luck.

Peter

 

[Stephen B]

Hi Chris

In order to reduce the effect of wood movement (that causes the tops to warp) try and alternate the grain of the boards before joining them. If you look at the end grain you will see how the grain runs (might be bottom left to top right, top left to bottom right, a open curve upwards or an open curve downwards).

Do not get to fixated about the number of dominos. I would think that no more than 4 along each length would easily be enough. When I break down really old furniture in order to salvage the wood I rarely see floating tenons between the boards, it is usually just glue alone. That said, I would use a few dominos to help with alignment.

Do not put a silly amount of pressure on whilst clamping. The pressure should be enough to bring things together but not enough to force all of the glue away from between the boards.

When clamping, alternate the clamps so that one is fitted from one side and the next from the other. That way any cupping cause by clamping will be eliminated.

I have said all of this on the assumption that your wood is dry or its moisture matches the destination location for the finished piece.

Good luck.

Peter

[size=13pt]A master class of all the basics.

[member=11196]Peter Parfitt[/member]

 

[Bob D.]

If you do decide to use those pieces of angle as clamping cauls, be sure to put some wax paper between them and the wood. Otherwise, just like with pipe clamps wherever the steel comes in contact with the glue you could get a stain in the wood which will be difficult to remove.

You could add a breadboard end to the table top using dominos or a spline which will help to keep the surface flat over time.

Check out this unique support for the leaf that Norm used on a drop leaf table he built in the first season (S01E03) of the NYW. No hardware except for a screw. It might give you some ideas on how to support your leafs. I have also seen a pair of slide out style rails like those you would see on a secretary desk.

 

[Naildrivingman]

Thanks for all the replies.  I did employ the alternating board technique (when possible for appearance).  I will employ the use of cauls next time.

I think the main culprit in the warping was clamp pressure.  I think I used too much pressure because the joined edges were not completely straight. I know what I did wrong.  The lumber I used was live edge and rough sawn.  I opted to straight line on my table saw using a known straight edge and my highly skilled eye [wink].  I think this time I will employ my TS75...duh.

I'm confident that with all the tips I've received and a few alterations I've concluded, this project will turn out fine.

Thanks,
Chris

 

[Birdhunter]

I have tried gluing table tops up in sections rather than all at once. It's easier to fiddle with the alignment while clamping. It's easy to sand out any irregularities. The final glue up is with the two halves going together, but it's only one joint. You know all the other joints are good and only have to worry about the last one.

To explain.... if my top has 6 boards, 1 & 2 are glued, then 5 & 6. When those are dry and rough sanded, 3 is glued to 2 and 4 is glued to 5. When those are dry, 3 is glued to 4. Any sequence works, but the idea is to keep the glue up simple as possible.

I have a Performax open end drum sander that works well to flatten small panels.

I did one project that had a top that exceeded what my drum sander could handle. I took the top to a Woodcraft. They charged me $10 to flatted the top and even sanded it down to 220 for me. They had access to a large drum sander.

 

[Cheese]

FWIW...there is a local vendor, Forest Products Supply that will for a small $30-$35 fee, run the completed table top through their Timesaver. The max width is 48".
http://www.forestproductssupply.com

 

[Naildrivingman]

I'm planning on gluing up today.  I' m wondering if it is necessary to glue the dominos in?  I don't need them for strength, as the entire length will be edge glued.  I am simply using the dominos for alignment purposes.

Thought?

Thanks,
Chris

 

[Bob D.]

"...Additionally, I would like to create the drop leaf mechanism from hickory and avoid modern hardware (hinges exempt of course).  I am not opposed to modern drop leaf hardware if I cannot easily be seen.  Any suggestions of this mechanism with pictures/links appreciated."

What have you decided on for the drop leaf mechanism?

 

[Naildrivingman]

Thanks for the link to New Yankee Workshop Bob.  I have seen that particular mechanism on the Internet, but was not completely satisfied with the slight deflection of the leaf. I will either use a conventional piece of hardware or I will use a solid Hickory through bolt with a wedge on the leaf to draw the leaf tight to the table.  My first choice would be the Hickory through bolt, but I have yet to completely design how it will work. This is not my idea, it was something I saw on the Internet but I cannot locate it now.  I I have yet to upload pictures of anything, but I will be taking pictures of this project during its various phases and when the time comes I will post.

 

[Naildrivingman]

The glueup went pretty well.  I realized after that I made a mistake that most others probably wouldn't.  I started with 4/4 rough hickory. I surface planed to 3/4".  Upon assembly there were still some variations in plane due to the board's cambers.  Most of these discrepancies are at the edges even though I placed my first dominos 2" in from the edges. I shouldn't have placed so much faith in the domino's ability to align these boards, but rather I should have stopped planing at 13/16" or so, thus allowing for surface loss in the sanding process.  It's a mistake that I have to believe is due to my inexperience in the glueup process.  Fortunately, I will be applying a routed edge treatment that I hope will soften the appearance of the thickness differences.  Would a bread board end cap help at all?

I'm taking pics as I go and will post once I figure out how to do it.

Thanks for all advice so far.  Keep the tips coming.

Chris