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.

[Alan Lightstone]

I always clamp squares to opposite corners (and all 4 corners if I can). Then check the diagonals, and they are usually spot on.

Pipe clamps can easily pull a case out of square. Frustrating, no doubt.

[Ron Citerone]

Clamp “Anxiety” I call it. Interesting how many comments about pipe clamps as a culprit.
Since I am a hobbyist, and time is not money, I have started gluing carcasses up in 2 steps. Making sure the glued up joints are square, Then gluing the other joints the next morning. I believe my results with this method is much better.

[Ron Citerone]

Only gluing half the joints each time also gives you a little more working time to make adjustments too.

[andy bessette]

...Since I am a hobbyist, and time is not money, I have started gluing carcasses up in 2 steps. Making sure the glued up joints are square, Then gluing the other joints the next morning. I believe my results with this method is much better.

Actually I see no advantage in taking twice as many days to do a glue-up. Once you do a dry fit you'll know if it will come out square. If it doesn't come out square it is because you didn't check the diagonals.

I do this for a living. Time really is money, even if you're a hobbyist.
"Time is a bitch when you take it for granted." -- Bugsy Segal

[Kevin Jenness]

Ian Kirby wrote an article entitled "Gluing Up" in Fine Woodworking #31 that sums up the process clearly. https://www.finewoodworking.com/1981/12/01/gluing-up

[Doug Garson]

Haven't tried this, but I'll throw this idea out there for comments. Put a clamp or clamps across the long diagonal and snug it up, tight but not too tight. Then go around the glue joints with a heat gun gradually heating up the glue and after say ten minutes tighten the clamp(s) a bit and then measure to see if the carcass has squared up. If it improves but not enough, continue, if it's good enough, let it cool and before you release the clamp(s) install the back panel. As I said, haven't tried this but got the idea from watching Thomas Johnson's videos where he often uses heat to soften glue (often hide glue) when disassembling glue joints.

[Tom Bender]

This should not be problem on a dresser. It will not be visible and there are no doors, just drawers. If these are inset, just trim the fronts to the openings. That's the time to do it and for this reason. If it wobbles, trim the feet.

[Warren Lake]

some shops clamp corner blocks in every corner friend worked in a top shop in toronto and they did that there.

[Dave Zellers]

some shops clamp corner blocks in every corner friend worked in a top shop in toronto and they did that there.


This is the key and Alan Lightstone mentioned it as well. And don't buy them- make them. They don't need to be machined to absurd tolerances. Make at least 8 of them. I used a very nice grade of 3/4" UL ply. For next time as you said. :)

Clamp the corners and sides square as you assemble. It makes all the difference. You will also find other uses for them once you have them.

[Warren Lake]

they were made from off cuts from other jobs usually laminate on both sides not sure if I have any around will check. His shop had all kinds of things I didnt see in other shops the best shops lots of europeans had a guy, the guy had metal work machines and he made stuff. They usually didnt share stuff with other shops as they all competed for many of the same jobs. Survival in the real world.

[Dave Zellers]

They usually didn't share stuff with other shops as they all competed for many of the same jobs. Survival in the real world.

So true. So true.