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+-- Thread: Big table top! (/showthread.php?tid=7375629)
Big table top! - iublue - 04-14-2024
I am finishing up what I consider an odd sized table. It is 5' x 5' out of 1 3/8" thick walnut. Heavy top, so heavy that since I work by myself, I had to design a apparatus to move and flip the top over.
The schrinkulator calculates an 1" of movement if I put in the high value of 12% and the low value of 6". I would think that would be the extremes or at least I hope so!
I was going to use figure eights to fasten the top to the apron but I am concern that figure eights would not handle that much possible movement. Thoughts?
The base is 35" x 35" with 5" x 5" legs and 2" x 5" aprons. I was only going to put the figure eights parallel to the grain. Would it be a mistake not the attach the sides of the table to the base in some way? Once again, there is a potential of a considerable amount of movement.
Thoughts?
Thanks,
Toney
RE: Big table top! - Bill Holt - 04-15-2024
No expert here...but I built a 60" round walnut table for our daughter about 15 years ago. I believe it was John Fry who gave me the courage to move forward. The brain trust here, offered the opinion that since the top was a glue up of 6-to-8-inch boards the movement would be drastically reduced, especially in a controlled indoor environment. I used figure eights and there have been no issues.
RE: Big table top! - jteneyck - 04-15-2024
It's good to plan for the extreme, and hope it never happens. Much better than the other way around. I don't really understand how figure 8 fasteners allow for wood movement w/o something pivoting, just seems odd to me. I would use buttons or Z-clips on the aprons where the top goes cross grain. I made this table a few years ago, something like 42" x 96". Here's what the base looked like.
![[Image: AP1GczNCSYQ9bRhl4ewCxQctPAtAxTETVmbmxk7e...authuser=1]](https://lh3.googleusercontent.com/pw/AP1GczNCSYQ9bRhl4ewCxQctPAtAxTETVmbmxk7eYVWDhMewPvioIkbDTKYVH7UMRgc8s9QfRFXD6NHjUBMdhEHK5PDcL-UCXF_R2RTYMEAlz7sMebSBS_vaIJKElvPgFn6mUw9pwtqiblCpL__7PsQPrXiaPw=w1460-h821-s-no?authuser=1)
Not shown here, but I cut a dado around the inside edge of the end aprons and cross stretchers with a biscuit jointer. They cut a perfect groove for Z-clips. Three clips along each member. The top can do as it wants with no worry of binding/splitting from how it's held to the base. Bonus points if you add a dowel locator at the center of the short aprons to center the top or, alternatively, use pocket screws. I didn't.
john
RE: Big table top! - wing nut - 04-15-2024
(04-15-2024, 07:16 AM)Bill Holt Wrote: No expert here...but I built a 60" round walnut table for our daughter about 15 years ago. I believe it was John Fry who gave me the courage to move forward. The brain trust here, offered the opinion that since the top was a glue up of 6-to-8-inch boards the movement would be drastically reduced, especially in a controlled indoor environment. I used figure eights and there have been no issues.
off topic, but whatever happened to John Fry, I remember his post.
RE: Big table top! - jteneyck - 04-15-2024
(04-15-2024, 10:03 AM)wing nut Wrote: off topic, but whatever happened to John Fry, I remember his post.
He posted a couple of times a year or two ago, but then went dark again.
John
RE: Big table top! - Stwood_ - 04-17-2024
I always figure a 1/4" shrinkage every 12" of width on air dried lumber. Kiln dried is much less normally, or should be.
I built a 5'x12' 2" thick oak dining table top that the customer wanted end caps. I hesitated, but did. So I told him I could not guarantee the table stayed matched to the end boards.
And it did not. I went back 2 months later to install 80' of bendable handrail on wrought iron newels and railings, and the table had shrunk a 1/4" on each side, exposing the bread board ends.
RE: Big table top! - blackhat - 04-24-2024
Finish doing the math. At centre there is 0 movement if it’s fastened. 1/2” from center to each edge. Halfway from center to edge ( 15” ) there’s 1/4”. That’s more easily digested. It’s still more than I would be comfortable with fig 8s. Z clips or wood buttons with a tongue riding in a groove in the apron would be my choice.
RE: Big table top! - Gary G™ - 04-24-2024
I would use shop made buttons.