Wobbly Table - Why?

[Busdriver]

I built a counter height table. Square top. 30 x 30 inches. 38 inches height. 3 1/2 x 3 1/2 legs with aprons attached.
Pretty much top, legs, aprons. That's all.
When I built it, everything piece of wood is flush with its counter part.
Anyway, when I dropped off the table at the buyer's house, the table was wobbly. Owner didn't think the floor was off level.
The legs were cut the same length with a stop block, everything flush. I used pocket hole jounery.
What did I do wrong?

Eddie

[Busdriver]

If the legs are the same length and flush with the top of the aprons, there's nothing else that could be wrong besides the floor being off, correct?

Eddie

[Bibliophile 13]

This makes me chuckle.

Not at you, though.

First rule of finish carpentry, built-ins, and furniture installation: nothing in a house is ever plumb, square, or level. Ever.

In other words, as long as you measured carefully and build everything square, you did nothing wrong. Between variations in the flooring and the inevitable wood movement here and there, it would have been a small miracle if the piece HADN'T wobbled a little when you put it in place.

There are a number of things you can do about it. If it won't be moved, you can tap a shim under the "short" leg. If you do it right and don't leave it sticking out past the leg, it will never be seen. Use a bit of glue on the top of the shim if you're worried about it working its way back out over time. There are also hardware devices that allow you to level a table, like what comes standard on large appliances like stoves and washers.

[jteneyck]

If your joinery wasn't really good you could easily have pulled the base out of alignment when you screwed it together.  You should have seen that, however, afterwards when it was sitting on your bench, assuming your bench is flat.  If your bench isn't flat you need one that is.  Also, if the top wasn't really flat it could have pulled the base out of plane when you attached it.  

Get two sawhorses and use winding sticks to get them in-plane.  Tip the table over and lay it on the sawhorses.  Put a winding stick on opposite legs and see if they are in-plane.  Move them 90° and check the other way.  I'll bet you find they aren't in-plane in one direction or the other.  If so, you could take the top off and use the winding sticks to check the base again and the top, too.  You may find both are out of plane a little.  If so, you may be able to pull it back into plane by changing the orientation of the top to the base.  If that's a no-go, a small shim or two between the top and base may do it.  If still no good, find the long leg and sand it down until all the legs are in-plane.  Do that after the top is back on.  

John

[jteneyck]

I built a counter height table. Square top. 30 x 30 inches. 38 inches height. 3 1/2 x 3 1/2 legs with aprons attached.
Pretty much top, legs, aprons. That's all.
When I built it, everything piece of wood is flush with its counter part.
Anyway, when I dropped off the table at the buyer's house, the table was wobbly. Owner didn't think the floor was off level.
The legs were cut the same length with a stop block, everything flush. I used pocket hole jounery.
What did I do wrong?

Eddie

On a separate issue, did you use pocket hole joinery to attach the breadboard ends to the main field of the top?  

John

[mike4244]

I built a counter height table. Square top. 30 x 30 inches. 38 inches height. 3 1/2 x 3 1/2 legs with aprons attached.
Pretty much top, legs, aprons. That's all.
When I built it, everything piece of wood is flush with its counter part.
Anyway, when I dropped off the table at the buyer's house, the table was wobbly. Owner didn't think the floor was off level.
The legs were cut the same length with a stop block, everything flush. I used pocket hole jounery.
What did I do wrong?

Eddie

If the table did not wobble in your shop, then the clients floor is the problem. Do a search for table leg levelers, they range from $8.00 to $30.00 for a set of four. 
mike

[Busdriver]

Yes I used PH screws to attach the aprons to the top.

[Timberwolf]

Yes I used PH screws to attach the aprons to the top.

.........................
I suspect the floor....If it is "off flat" by 1/16" the table will wobble a little....Just because it is "level" does not mean the floor is "flat". I would check the floor with a known straight edge.

[cvillewood]

Just because the legs are exactly the same length doesn’t mean the table won’t have some wobble. The ends of the aprons might be out of square a hair, or the pocket screws twisted the legs a little. Those can cause a things to get out of square/alignment and cause wobble.

After I finish a table I check it on a known flat surface. If it’s got a wobble I trim a long leg accordingly on the table saw with the blade barely above the table.

Or, the customer’s floor could be off.

[jteneyck]

Yes I used PH screws to attach the aprons to the top.

Uh oh.  You shouldn't be surprised if you get a call from that customer in a few months.  

No disrespect, but you would benefit from reading a book or two about time tested furniture construction methods.  

John