What have I done wrong? Carcass not square

[Mjward]

Thank you. I’ve genuinely never ‘squared’ a cabinet; if there’s ever any slight discrepancy, then adding the back to the cabinet squares it up. I’ve never used the ‘5 cut method’ for checking for square. Things are square, not square, or square enough. Which are yours?

edited to say thank you!

this was one of my several errors...i.e. not using what was a square back to square it up and instead nailing the back on and flush cutting back with the router assuming incorrectly it was the back I had made badly.

As others said, its to space the cabinet correctly and have a good fixing point for the worktop. Kitchen carcasses generally have a rail about 100mm deep at the front and a rail mounted on the back to strengthen the unit and locate the top of the infil panel.

I'm sure the o.p simply made his carcass as a full box for simplicity. The manufacturers just use rails to save material.
I made a built in unit for our front room last year and used 2 rails on the carcass tops, with a 6mm back panel. I wouldnt be adverse to using a full top, but i managed to save buying an extra sheet, of which i would have only needed maybe a third of..... its only a couple of quid if you've got the material

Yup was a combination of simplicity but I also thought the full sheet would do a marginally better job of distributing the load above although in reality it won't back a blind bit of difference as the top carcass will be a hanging rail i.e. the weight will be bearing down on the sides regardless.

Some excellent advice and reference sources... Often amazed by just what assorted pholks here can and will offer by way of help.

My only 2 cents worth... are that when one views your second picture one can see that the bottom left corner is out a little - let alone what may be happening with the wall; or else that wee "square" is clearly not "square". When I view that picture I note (abet a small) internal vertical error there?

As for fitting the "top" out/over the two sides, rather than inside the two sides that will allow some minor adjustments - if needsd; whereas as you have done it there is no minor adjustment option at all??

what you've spotted was the epiphany moment... "corr that wall is quite a bit out" *gets spirit level* ... ah no, that would be my carcass that is out

Seems a lot of bother. A sheet of MDF over the top, rather than in between, much easier to fix with glue and round head nails (pre drilled).

I dare say that in the real world it probably makes very little difference when considering normal loads but probably has come down to teams of engineers on the commercial side doing stress tests and working out which method "technically" held out better and I suspect from a commercial assembly perspective it didn't make a blind bit of difference to their process which way they did it so it became the norm

I think it's been mentioned before in this thread, but pocket hole joints do have a tendency to move slightly when screwing together, and consequently need some sort of clamping while screwing. Dowels, on the other hand, are fairly bulletproof, in my experience.
In my opinion...

Funnily enough ordered myself a dowel jig last night (in addition to a lot of clamps, clamping squares, engineers squares and other devices to prevent this happening again). My recent usage of pocket holes is almost single handedly due to YouTube/Tiktok videos (mostly US based) of when I've searched up "carcass/wardrobe MDF/plywood assembly" etc. In my limited experience I have found them absolutely fine with MR MDF and a low torque setting on the drill BUT will try it with more clamps on Monday and if I can't get to grips with screwing without a shift I will ditch that process.

Regardless of how that goes, will have a practice with the dowel jig as my very first (free hand) dowels this week went very well and dried to make a very strong bond. I like the fact that with the dowel you not only have something that helps bond the pieces but works brilliantly to line them up for screws as well and I think going forward that might be the better assembly method.

Once again, this has been supremely useful/educational and if I have built in wardrobes that haven't collapse within the year, it's due to the help of every one of you. Thanks!

 

[hlvd]

You need to measure diagonals as a square won’t give you a true representation of squareness.
You also need to make sure your level spans the two corners and not the sagging middle of the cabinet, as that also won’t give you a correct reference.

You also need a false top on that cabinet as it doesn’t look correct in between the two sides.

 

[Jacob]

Not suggesting you should follow this, it depends on what facilities, tools and skills you have, but, come to think, if I wanted to build in a chest of drawers / wardrobe the last source of design/construction inspiration would be B&Q or Wickes.
I would probably have built a face frame, depending on design details, then fixed it to horizontal battens attached to the walls each side. Perhaps a vertical batten down the right hand side. That would take me to where you are so far, but faster, with a fraction of the materials and dead straight and level. No need for a plinth, nor boards at the back or the sides, except to close the gap on the left.
We had something similar in my childhood home - a sort of welsh dresser built in to a corner of the kitchen (no alcove), with drawers below, cupboards above and a gap in the middle for a work surface. No plinth but the rooms skirting boards were continued around the base, leaving a void under the bottom drawer. The left hand side extended floor to ceiling with a bit of a flourish in the middle , like a welsh dresser.
Just a thought, ignore this, it's all a learning curve - carry on! And I have Ikea kitchen units.
PS the whole point of "building in" is that you don't have to build a cabinet. It's simpler and cheaper.
If you are building a cabinet it might as well be freestanding but to fit the space, and square to itself but not necessarily to the walls.

 

[Mjward]

I hear you but personal taste, I loathe "built in" units that are how you describe and the inside of your wardrobe is the cold external facing walls and a plastered wall finish. A carcass is the only way for it to actually be a built in wardrobe as opposed to a wardrobe facade as you describe

 

[Jacob]

I hear you but personal taste, I loathe "built in" units that are how you describe and the inside of your wardrobe is the cold external facing walls and a plastered wall finish. A carcass is the only way for it to actually be a built in wardrobe as opposed to a wardrobe facade as you describe

As far as I recall the backs of our home built-in dresser were just unseen plaster behind the drawers, but matchboard behind the cupboards, where visible.
Many ways to skin a cat!

 

[cowtown_eric]

myward wrote

"Corner to corners being equal ensures its square, always use the largest square you can to check square edges and the same with spirit levels because you are after the average over the length and not just a small section. "

with carcase construction that's a good check , until you screw it to an out of plumb walll! -which induces torque into the carcase.and makes it out of square

Add into that equation a wonky level, and out of square plastic appuratnenace-pseudo device, , and you've got a puzzle to solve.which takes a lot of time!

I'd suggest you go back to basics- check yer level, check yer squares and those little plastic gizmos

Make it square and plumb, install it level and plumb, and you don't encounter problems like this., and if you go with the "close enuf" perspective, ---expect to see a whack of time spent of fitting doors and adjusting them.

A wonky level, a "bad square" even a trashy tape measure will bite you back in every step!

Eric in the colonies

 

[Mjward]

Mostly a day of learning/calibration today
1) one of the spirit levels was neither level nor plumb
2) quick square, plastic square and L square fine but rafter square not 90 degress (acquired new engineers square and clamping squares which were both fine).. oh and made my own L squares (with clamping holes) for the long lengths and tested them
3) got dowel jig but first impressions aren't great, don't think it's massively easier than when I did free hand/tape measure but probably just my inexperience
4) upgraded from generic Amazon countersink bits to trend hex bits, more convenient sure but don't feel as sharp
5) my DeWalt wood hole drill bits were feeling a bit blunt and got a Bosch set...very impressed

 

[cowtown_eric]

There is a reason why God invented shims!!! Glad you found the wonky level and out of square rafter square...!!!

Eric

 

[Jacob]

Mostly a day of learning/calibration today
1) one of the spirit levels was neither level nor plumb
2) quick square, plastic square and L square fine but rafter square not 90 degress (acquired new engineers square and clamping squares which were both fine).. oh and made my own L squares (with clamping holes) for the long lengths and tested them
3) got dowel jig but first impressions aren't great, don't think it's massively easier than when I did free hand/tape measure but probably just my inexperience
4) upgraded from generic Amazon countersink bits to trend hex bits, more convenient sure but don't feel as sharp
5) my DeWalt wood hole drill bits were feeling a bit blunt and got a Bosch set...very impressed

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Too much kit and a lot of overthinking.
I'd keep one tape measure, one combi sliding square, one spirit level. Bin the rest, especially home made squares.
Best for plumb is a piece of string with a weight on the end. Can be incorporated into a board, or a wooden set square, in the old fashioned way.
There's a simple "Catch 22" dilemma with precision - the more precise your kit the more errors you will find - ad infinitum.

 

[Tris]

My memory isn't always 100% but didn't someone on here post a simple design for a stick gauge for checking diagonals?

edit: Pinch sticks

 

[Distinterior]

A " Square of Thales" I think they're called...?

 

[Mjward]

Too much kit and a lot of overthinking.
I'd keep one tape measure, one combi sliding square, one spirit level. Bin the rest, especially home made squares.
Best for plumb is a piece of string with a weight on the end. Can be incorporated into a board, or a wooden set square, in the old fashioned way.
There's a simple "Catch 22" dilemma with precision - the more precise your kit the more errors you will find - ad infinitum.

You're not wrong!

A " Square of Thales" I think they're called...?

bizarrely literally just watched a youtube on this as I found a forum thread from 2019 discussing a similar issue.

 

[Citracal]

Doesn't help that building with mdf and pocket screws is only a step away from building with cardboard and nails! Your top piece should at the very least sit on top of the sides rather than between them. Any weight there and it would bend or break away completely.

"A step away from cardboard and nails"

 

[Jacob]

My memory isn't always 100% but didn't someone on here post a simple design for a stick gauge for checking diagonals?

edit: Pinch sticks

It's a very simple design; you just need a "long enough" stick. If it's "too long" you might need to cut a bit off, but I wouldn't want to open a discussion on what saw to use or we'll be here all night!

 

[Mjward]

Just a quick one to say thanks again for all the advice and tips etc. Situation rectified and lessons learnt for next time. We have matching diagonals

 

[paulrbarnard]

Just a quick one to say thanks again for all the advice and tips etc. Situation rectified and lessons learnt for next time. We have matching diagonals

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That looks to be a half mm out. You’ll need to do it again.

 

[Mjward]

That looks to be a half mm out. You’ll need to do it again.

Goddamnit into the log burner she goes! (Actually maybe not given its cardboard/MDF)

 

[baldkev]

Too much kit and a lot of overthinking.
I'd keep one tape measure, one combi sliding square, one spirit level. Bin the rest, especially home made squares.
Best for plumb is a piece of string with a weight on the end. Can be incorporated into a board, or a wooden set square, in the old fashioned way.
There's a simple "Catch 22" dilemma with precision - the more precise your kit the more errors you will find - ad infinitum.

Dont forget to tell him about the virtues of an axe for shooting in doors
On a serious note, having plenty of levels and squares etc isnt a bad thing, especially when they are spread around a site ive got about 8 tape measures spread around my current job

 

[Jacob]

Goddamnit into the log burner she goes! (Actually maybe not given its cardboard/MDF)

MDF burns really well in a wood stove! Best thing for it.

 

[Jacob]

Dont forget to tell him about the virtues of an axe for shooting in doors

Axe is good for scribing, indoors or out! Used to be a standard item of kit

On a serious note, having plenty of levels and squares etc isnt a bad thing, especially when they are spread around a site ive got about 8 tape measures spread around my current job

Yebbut not if you start comparing them side by side and looking for perfection.