Squaring carcass question

[Brian Runau]

I glued up a dresser yesterday. @ 47" tall x 40" wide. I used domino tenons and had four stringers, top/bottom and front back. I was very deliberate in making sure all my equipment was set properly before cutting and wood. Table saw was 90 and parallel etc.. jointer 90 so I could get a true 90 side.

All the legs and stringers were cut to length using a stop so they would all be the same length.

While gluing up and clamping I measured for the bottom front stringer to make sure it was in the right height location and 90 to the leg.

After checking all the stringers for square, before and after clamping up the measurement across the two corners was off by </= 1/8". I tried to take this out, but it would not move for me (probably did not perform the right step).

If all the stringers are in the right locations and square to the legs, how is the 1/8" being introduced into the piece? Not sure where this is coming from in order to eliminate it in the future.

Thanks.

Brian

Brian

[Jim Becker]

Sometimes this happens during a glue-up and correction to square is a matter of a clamp across the longer corner-to-corner to bring it back to square before the adhesive sets up.

[Mark Wooden]

+1 about squaring the carcass before the glue sets; sometimes even the most careful clamping can rack a glue up.
Sometimes a spring brace inside the carcass can be used to push it back to square while glueing when a clamp outside isnt practical for some reason.

[Kevin Jenness]

It is most likely due to clamping forces. You can do as Jim suggests or adjust the direction/location of your clamps/cauls slightly to get the diagonals equal. 1/8" isn't a lot on a piece that size but you should be able to get it closer. A one piece plywood back can help to square up the carcass.

[Brian Runau]

Thanks men.

It is glued up and it has set, so nothing I can do this time, but next time.... thanks. brian

[Richard Coers]

It's really pretty easy to pull a case out of square. Pipe clamps seem to be the worst. Just moving the head or foot of the clamp out 1/2" can make the case right or wrong in a glue up.

[Lee Schierer]

Thanks men.

It is glued up and it has set, so nothing I can do this time, but next time.... thanks. brian

I feel your pain. I've had the same thing happen. Now I check the diagonals as I add and tighten clamps. Clamping can pull/push things out of square so check often while clamping. Clamping can also bow rails or panels which causes things to appear out of square when they won't be when the pressure is removed. Sometimes it helps to just assemble one corner at a time to help keep things square while clamping.

[Jeremy Thornton]

Does using dowels help keep it square?

[Rich Engelhardt]

Does using dowels help keep it square?

Not as well as pocket screws have - for me anyhow.

[johnny means]

A 16th out for a case that large is absolutely acceptable in my book. Without machinist tolerances in all the joints, you're never really going to be able to guarantee perfection. You could clamp it square while the glue dries, but it's likely to spring back once unclaimed, anthem tweaking would probably just be flexing of the material. Only opening the joints would truly square things up.

[Mel Fulks]

Yeah, check diagonals. And unless feet are made just a bit higher than “right size”….one won’t reach the floor !

[andy bessette]

A full-size layout on the bench helps with an overlayed prefit dry assembly prior to glue-up. Also aligning the glue-up over the square edges of the assembly bench remove the guesswork in squaring.

[mreza Salav]

Yes, no matter how accurate your pieces are in an item that size you should check the diagonals after you have tightened the clamps and put a clamp diagonally if needed. That is what I do anyway.

[Warren Lake]

not always easy to check with clamps all over depending on the glue up. Even a bit out is extra greif fitting doors and drawers. When I had a crappy sliding table attachment remember having one gable out and that canted stuff and made all the fitting more grief. that will relate to what tolerances you use.
'
Some old guys take a cabinet that is out of square and thump it on a piece of carpet on the floor on a diagonal on the saw bottom edge. Sometimes there is a sound, it doesnt break but squares up better. I saw an old british guy do this and it did work. If you have a face frame forget it.

[Robert Engel]

A 16th out for a case that large is absolutely acceptable in my book. Without machinist tolerances in all the joints, you're never really going to be able to guarantee perfection. You could clamp it square while the glue dries, but it's likely to spring back once unclaimed, anthem tweaking would probably just be flexing of the material. Only opening the joints would truly square things up.

Same here.