Table top issue

[Gregory Mosher]

Hello folks,

I recently made a harvest table, and was having an issue with the table top. It was made of planed and jointed 2x4 spruce, 8 ft long. I joined it using biscuit joinery #20's, and glued the biscuits and glue along the edges and clamped tight. It had three panels seperately joined so I could pane the three panels in my planer, and glued and biscuit joined the panels.

My issue is it seems that the last panel joined up seemed to ramp up lengthwise about 1/4". I fastened it to the end frames using lee valley table top fasteners, and when I added the screws it seemed to suck it back down so it all was flat. Is this going to be an issue? I've been racking my brain about why it happened since it all was the exact same dimensions. The only thing different would be the slot for the biscuits connect the last panel to the middle one was slightly lower than the others I noticed. it was slightly below half the width instead of directly in the middle like the others. Would cause the issue where it ramps that whole up?

Cheers

[Don Orr]

I'm not really a furniture builder but I know a bit about wood qualities. My semi-educated guess is the material itself is a large part of the problem. Dimensional lumber (2x4, 2x6, etc. softwoods) are notoriously twisty due to how the trees are grown, harvested, milled, and dried. If you look at the grade stamp on your boards you will probably see a "KD 19" somewhere. That means kiln dried to 19% moisture-pretty wet. Even if you allowed them to acclimate in your shop for a while, they will still be drying as you work them and can move substantially. If they are nice and dry to your local EMC, there can still be reaction wood from how they grew.
For what it's worth 1/4" over 8" is not much to worry about since it easily pulled down to your base. If it becomes a problem later it's just an excuse to build another with your increased knowledge and skill.

[Gregory Mosher]

Thanks for the thoughts Don!

[Andrew Hughes]

I agree with Don it’s probably not your fault. And since your fastening pulled it down to the apron I would call it good.
Too bad you didn’t get more comments it’s a shame so many are obsessed with the silly tariff thread.:(

[julian abram]

It couldn't be explained any better than what Don said. He hit every nail on the head.

[Lee Schierer]

As Don said construction lumber usually has a higher moisture content than cabinet grade wood. It is not unusual for it to twist, bend, warp cup or all of these when you work with it. Planing more material from one side than the other will imbalance the tension and all sorts of movement can occur. If you plan to continue making furniture a moisture meter is a sound investment.

[Gregory Mosher]

Is a certain moisture content I should be be looking for before I plane and joint it?

[Lee Schierer]

Is a certain moisture content I should be be looking for before I plane and joint it?

I normally work with kiln dried lumber that is at 7%. I recently completed a project from hickory that was at 10% and I saw little movement in the boards, but I was not planing them. It has been in my shop since February and it now reads 8% on the exterior. I worked with lumber years ago that was at 12% and had nothing but trouble. Remember it can take 6-12 months for moisture to change on the interior portions of a board and thicker boards take longer for the insides to change.

[andy bessette]

...the slot for the biscuits connect the last panel to the middle one was slightly lower than the others I noticed. it was slightly below half the width instead of directly in the middle like the others...

This mistake could have easily been corrected by gluing biscuits in the mislocated slots and re-slotting them.

[Rick McQuay]

I occasionally use construction lumber but only after it has sat in my shop for a year or more. Bow, cup, and crook can be dealt with but twist should be avoided. If a board is twisted when you begin, it'll twist again.

[Doug Garson]

Did you use cauls when you glued it up?

[Robert Engel]

Is a certain moisture content I should be be looking for before I plane and joint it?

Its not the absolute MC, its whether the lumber is in equilibrium with the environment.

IOW, what's good in Arizona won't work in South Florida.

BTW, my son is a quite accomplished cellist he has had instruments crack going from FL back to CO.

[Wade Lippman]

I am confused. You put biscuit slots in the wrong place and wonder why it isn't flat? I must be misreading it.

[Gregory Mosher]

Lee- I'll invest in a moisture meter and keep an eye on it. I don't have room to store it for so long before working with it. I just get orders and fill them as they come in, so construction lumber likely is a red flag eh?

Rick- good to keep in mind, thanks!

Doug - Just on the two ends

robert - if it's sealed with a spar urethane, multiple coats, would that keep the moisture content from changing and causing issues from then on out?

Wade - in one of the panels yeah, i'm still a bit of a novice woodworker, I was always more of a finish carpenter working with trim, then started having clients request furniture pieces so i'm kind of learning as I go about certain things.