Squaring up Chairs

[Don L Johnson]

I'm dry fitting a mission style chair (three cross members per side at and below the seat level -- so lots of mortise and tenon joints). It's all "Bessy'd" up and sets flat on all four legs. I measured the inside diagonals at the seat level and one diagonal is about an eighth longer.

Should I worry about that since the legs are flat? I can't really rack it any other way, as all of the sholder cuts for the tenons pretty well set the limits.

Too much worry for too little of a difference, or do I really have an issue here? After I "proof" the first one, I'll be making 9 more. Thanks as always for your help.

[Cliff Rohrabacher]

While it's true that you joints will help make it square it's also true that you clamping method is hugely determinative and so is the surface upon which yo do this clamping.

If you are doing a lot of these chairs think about building a clamping fixture that will make sure you get the angles you intend.

If you just using a slow setting glue, clamps, and a square or bevel gauge to do one offs then make sure your table is dead flat. Tweak the clamps apply the angle gauge and tweak some more.

[Reed Wells]

Don, When I make chairs I try for square first, then if necessary a light sand on the bottom of the offending leg will make it sit strong on all four legs.

[Walt Caza]

Hi Don,
You raise an issue that sooner or later becomes a problem for us all.
Myself, I use the tablesaw top as my reference.
As Don said, I sand down the high ones, heading towards all feet level.

You can get most any 4-legged piece to either sit still 'level' on it's own, or with a couple slender shims---
and then scribe a pencil line around all four feet effectively transfering your reference surface.
You gotta lay the pencil right down the whole time. You do not need to remove material all
the way to your lines-just as a way to guide your efforts. Keep placing it
back on your makeshift surface plate, and check for rocking.

Watch you don't burn that end grain if using powered sanders especially disk.

The next colourful aspect of this...the surfaces where the furniture will
eventually live tend to stray from flat and level as well.

The smaller oak furniture I have been making, was all levelled by my best
effort on my Tsaw. Some come out of the clamps perfect, others need to
be massaged into cooperation. On the hardwood floors of my old house
some will rock here or there. I think foam stick-on feet will help with these
small variances. Some will compress to nothing, any 'floaters' will not.
Hoping for a tidier solution than shimming.

When my longer counters were installed into my newer kitchen in this
old house, the amount of material removed to scribe them level...
was nothing short of shocking!
Another idea might be to glue a couple coins as invisible shims that will
stay put? [not for chairs, sorry...I meant for furniture that belongs in one specific position...level it to it's home]
Chairs slide all around, so I guess you better do your best to level them in the shop.

Good luck with your levelling...
I say glue'em and sand your feet after dry and unclamped.
take care,
Walt