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Figure 8 Connectors

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Forum topic by Padriac Riley posted 01-20-2015 06:20 PM 1247 views 1 time favorited 13 replies Add to Favorites Watch
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Padriac Riley

36 posts in 734 days


01-20-2015 06:20 PM

Topic tags/keywords: wood movement seasonal figure 8 expansion solid question

So this may be approaching a massively stupid question here but for the life of me I can’t find any detailed info on using figure 8 connectors or how they allow seasonal wood movement. I have to attach some solid tops to a few dressers I’m going to be making. I have most of the design locked down but how to attach the top securely but allow for seasonal wood movement is proving to be the issue. I’ve seen the z clips but after digging around here and other places I think I like the basic idea of the figure 8 connectors attach much better. Lee Valley still sells the solid versions instead of the cheap stamped steel ones Rockler has so I’m good as far as finding them.

I know they get counter bored into the top of the frame (apron, rails, whatever) so they sit flush and then get screwed in. My difficulty in the understanding department is how do these connectors allow for seasonal wood movement? As I understand it once the top is properly aligned I then screw the other side of this rigid metal connector to the underside of the top? The attachment method would seem to defeat the purpose of the connector. Is there something very obvious that I’m missing?

The wood in question is Red Oak from Western Massachusetts if it matters.


13 replies so far

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firefighterontheside

13458 posts in 1318 days


#1 posted 01-20-2015 06:26 PM

I’ve never used them. I use the z clips. The 8’s really only work on the ends and not on the sides. On the ends they are able to pivot back and forth, but on the sides they don’t allow for movement. This is ok for a small top, but on something long it needs to be connected in the middle too.

-- Bill M. "People change, walnut doesn't" by Gene.

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jmartel

6565 posts in 1612 days


#2 posted 01-20-2015 06:27 PM

You would screw them in, but not so tight that the connectors cannot move. The connectors rotate during wood movement, so you would need to orient them such that the top will move parallel to the rail that they are mounted on.

-- The quality of one's woodworking is directly related to the amount of flannel worn.

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Padriac Riley

36 posts in 734 days


#3 posted 01-20-2015 06:33 PM

Kinda confirms what I was thinking but I was certain I must be missing something. Thanks for the clarification, I couldn’t find info on how they were supposed to work anywhere.

I would rather have the tops secured on all four sides AND be ale to move with the seasonal changes so good ol’ fashioned z clips it is.

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firefighterontheside

13458 posts in 1318 days


#4 posted 01-20-2015 06:38 PM

I prefer to attach it securely somewhere. On table tops I will attach it with glue and a screw in the very center and then clips out toward the sides. Mathis keeps the top always centered on the table. For a dresser I might secure it at the back so that the back is always flush and then it can move a bit at the front with the clips. I wanna say Norm taught me that.

-- Bill M. "People change, walnut doesn't" by Gene.

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Rick M

7910 posts in 1842 days


#5 posted 01-20-2015 06:38 PM

Figure 8’s work fine on side rails. I used them on my dining table. Use a Forstner bit to countersink the rail so the top will set flush. I installed mine on a slight angle so they aren’t resisting movement.

-- http://thewoodknack.blogspot.com/

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Padriac Riley

36 posts in 734 days


#6 posted 01-20-2015 08:36 PM

I’m curious why you would attach the dresser top at the back rather than the front. I would think for aesthetics attaching it with glue and screws at the front so the front two corners facing into the room would always look right and then let the back do what it needs to. Even if it’s right up against the wood work at the floor the back should have plenty of room to expand with no one the wiser. Unless you’re in a house with no wood work at the floor and frankly who needs those sick people.

Is there a reason I’m not understanding why the back would be better for the back to be the permanently fixed edge?

View Fred Hargis's profile

Fred Hargis

3933 posts in 1955 days


#7 posted 01-20-2015 08:46 PM

As Rick said, they work fine on the long rails, you just set them at a slight angle. I like both (Z clips and 8’s) and keep a supply of each on hand. I’m not much on using the z clips on the long rails, prefer them on the ends.

-- Our village hasn't lost it's idiot, he was elected to congress.

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bonesbr549

1176 posts in 2529 days


#8 posted 01-20-2015 09:19 PM

Used em on one project a big hutch thats in my dining room. Like others have said you just put them at a slight angle, and don’t torque them down and alls good. Mine going on 6 years now no issues and the top was large.

-- Sooner or later Liberals run out of other people's money.

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firefighterontheside

13458 posts in 1318 days


#9 posted 01-20-2015 09:19 PM

I figure a dresser top is gonna be no more than 24” deep, if that. I doubt the seasonal movement of that piece is gonna be more than 1/8” and will not be noticeable on the front if it goes from having a 1” overhang to a 1 1/8 overhang, but I might notice a 1/8” overhang on the back where it was flush before. I guess it is just a preference.

-- Bill M. "People change, walnut doesn't" by Gene.

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Padriac Riley

36 posts in 734 days


#10 posted 01-20-2015 09:56 PM

Ok that makes sense. The tops are actually exactly 24” deep but there is a 1” overhang all around so the extra 1/8” won’t be noticed no matter which way I let it go.

I have some 60 year old furniture that was first bought for my dad’s birth and has been passed through each of his two brothers and his sister, served me and my two brothers and my sister, and most recently (ok 20 years ago) served my daughter and is for now being used as my wife’s craft storage. The set has beaten on by many childhoods and shows no worse for the wear. I finally decided to take a peak inside earlier today on my lunch break to see what a success story had to say. All solid wood save the save and drawer bottoms which are 1/2” plywood and a fake bottom and top which are also plywood. The top looks like it is held on with nothing more than the wooden button version of the z clips with their tongues sitting in a slot around the upper frame members. I think I shall go with the z clips.

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firefighterontheside

13458 posts in 1318 days


#11 posted 01-20-2015 10:08 PM

I have never done the wood versions, but I know a lot of people still do. There is something to be said for being able to make everything in your shop.

-- Bill M. "People change, walnut doesn't" by Gene.

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Padriac Riley

36 posts in 734 days


#12 posted 01-20-2015 10:28 PM

I could make the wood versions – they obviously stand the test of time. Even knowing that I think I will go with metal z clips. I know it’s irrational because the wood versions will obviously take a beating, but knowing there is a tougher metal version available makes me want to shy away from the wood version.

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Rick M

7910 posts in 1842 days


#13 posted 01-21-2015 03:13 AM

I’ve done wood buttons on 3 tables. They hold up fine for the most part but I would recommend a wood that doesn’t split easily because I have had some break over years. Mostly that was my fault, my very first table I didn’t finish the top and bottom equally, then it was placed over a register and eventually the top cupped.

-- http://thewoodknack.blogspot.com/

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