What have I done wrong? Carcass not square

[Mjward]

Binge watching quite a few of @petermillard YT videos on making cabinets (there's a recent "basic boxes" one) would be helpful for you.

Big fan of his videos, I think he is the source of my mindset to put top/bottom panels between sides and not on top. Coincidentally rewatched his cabinet videos this morning and aside from many elements he does cover, he doesn't seem to spend an awful lot of time squaring up the carcasses ie he seems to have nailed a method for him with appropriate clamps and fixings etc.

Will try the pocket hole clamp but should that still create a bit of movement might try normal MDF screws and dowels where I can

 

[paulrbarnard]

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.

Ohh, controversy. I’m watching this now…

 

[baldkev]

Hold my beer while i sharpen my cabinet sides

Carcass construction is usually top and bottom panels mounted between the sides. Once the worktop goes over them, they arent going anywhere.

 

[Jacob]

Hold my beer while i sharpen my cabinet sides

Carcass construction is usually top and bottom panels mounted between the sides. Once the worktop goes over them, they arent going anywhere.

OK but why? If there's a worktop what is the mdf for? Would you fasten it up to the worktop to stop it falling down?
News to me - I've never made anything with MDF except some work benching where the MDF sits firmly on a timber frame and wall battens etc

 

[Inspector]

OK but why? If there's a worktop what is the mdf for? Would you fasten it up to the worktop to stop it falling down?
News to me - I've never made anything with MDF except some work benching where the MDF sits firmly on a timber frame and wall battens etc

Top is to space the sides and to fasten the worktop to. Sides cary the loads towards the floor. The top could just as easily been a pair of 100mm pieces front and rear the way many store bought cabinets, here at least, are made. Solid backs as the OP made are often just a 100mm strip across the back attached to the 100mm rear top piece, open to the wall. Sometimes the back is 1/8' to 1/4" thick for a touch nicer look inside. Strength all comes from when it is shimmed and fastened to the wall.

Pete

 

[Dibs-h]

Top is to space the sides and to fasten the worktop to. Sides cary the loads towards the floor. The top could just as easily been a pair of 100mm pieces front and rear the way many store bought cabinets, here at least, are made. Solid backs as the OP made are often just a 100mm strip across the back attached to the 100mm rear top piece, open to the wall. Sometimes the back is 1/8' to 1/4" thick for a touch nicer look inside. Strength all comes from when it is shimmed and fastened to the wall.

Pete

I had a similar thought to Jacob, i.e. if the sides are transmitting the load to the floor, why a full top if it's going to covered with a worktop.

So in this case - why a full top and not 2 stretchers (if that's the correct term), as you pointed out (100mm wide front and back)? In the both cases, you'd just screw upwards from inside into the worktop.

Is it because the OP wanted to do it that way (or thought he had to)? Or is there some benefit one way over the other?

Assuming all things are equal (level\balanced) - I can't see a full top being subjected to greater racking\torsional forces than the case where there are 2 stretchers (front & back).

 

[petermillard]

It's interesting you say that as the logic in me assumed that would make the most sense but when I started out, my research came back with people saying that the top/bottom boards go between the sides and not on top.

In commercial cabinetry, the top and base almost always sit between the sides. If you doubt that, head into your kitchen (or someone else’s (or B&Q/ Wickes etc…) showroom and take a look.

 

[petermillard]

Big fan of his videos, I think he is the source of my mindset to put top/bottom panels between sides and not on top. Coincidentally rewatched his cabinet videos this morning and aside from many elements he does cover, he doesn't seem to spend an awful lot of time squaring up the carcasses ie he seems to have nailed a method for him with appropriate clamps and fixings etc.

Will try the pocket hole clamp but should that still create a bit of movement might try normal MDF screws and dowels where I can

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!

 

[Jacob]

In commercial cabinetry, the top and base almost always sit between the sides. If you doubt that, head into your kitchen (or someone else’s (or B&Q/ Wickes etc…) showroom and take a look.

Yebbut this project isn't commercial cabinetry.
My Ikea cabinets have steel rails at top front and back which is equivalent to trad wooden rails, which would definitely sit on the sides.
I’ve never used the ‘5 cut method’ either. In fact I'd never heard of it! Had to look it up.
It's another world!

 

[petermillard]

Yebbut this project isn't commercial cabinetry.

And you shouldn’t adopt commercial practices, because…??

My Ikea cabinets have steel rails at top front and back which is equivalent to trad wooden rails.

And do they sit between the sides Jacob, or on top of them? I’ve never asked - and I know from what you’ve posted here that you’re a big fan of the traditional - but how much commercial cabinetry experience with sheet materials do you have?

I really liked the multi-coloured kitchen cabinet fronts you showed a while back, BTW; was that a one-off personal project, or a job?

 

[baldkev]

OK but why? If there's a worktop what is the mdf for? Would you fasten it up to the worktop to stop it falling down?
News to me - I've never made anything with MDF except some work benching where the MDF sits firmly on a timber frame and wall battens etc

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 had a similar thought to Jacob, i.e. if the sides are transmitting the load to the floor, why a full top if it's going to covered with a worktop.

So in this case - why a full top and not 2 stretchers (if that's the correct term), as you pointed out (100mm wide front and back)? In the both cases, you'd just screw upwards from inside into the worktop.

Is it because the OP wanted to do it that way (or thought he had to)? Or is there some benefit one way over the other?

Assuming all things are equal (level\balanced) - I can't see a full top being subjected to greater racking\torsional forces than the case where there are 2 stretchers (front & back).

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

 

[Dibs-h]

I'm sure the o.p simply made his carcass as a full box for simplicity.

I thought it might be.

The manufacturers just use rails to save material.

Another way of looking at it - is they don't use more material than they need to.

 

[baldkev]

Here you go @Jacob , See the screenshot below.
I think the fundamental difference here is that carcass construction isnt the same as say a welsh dresser. A carcass is a unit, designed to be used singularly or fixed to others, with a worktop over it ( modular construction ) whereas a traditional welsh dresser was joinery

 

[thetyreman]

I'd just fill the gap with caulk and accept it how it is, walls are never square straight or parallel, in fact I haven't found one example yet.

 

[trvlr]

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??

 

[trvlr]

Here you go @Jacob , See the screenshot below.
I think the fundamental difference here is that carcass construction isnt the same as say a welsh dresser. A carcass is a unit, designed to be used singularly or fixed to others, with a worktop over it ( modular construction ) whereas a traditional welsh dresser was joinery

great reference and link too...

 

[Jacob]

Here you go @Jacob , See the screenshot below.
I think the fundamental difference here is that carcass construction isnt the same as say a welsh dresser. A carcass is a unit, designed to be used singularly or fixed to others, with a worktop over it ( modular construction ) whereas a traditional welsh dresser was joinery

Not that different from a trad chest of drawers except the carcase would have top and bottom dovetailed to the sides - wide tails on the horizontals, to bear the weight. Smaller pins on the vertical sides. Or front and back top rail also dovetailed. With variations!

 

[trvlr]

after viewing robgul's video link - tres useful it was too... there was this on youtube:



Thus chap is truly remarkable.. Just wish one had his workshop and kit. Perhaps some details of the assorted goo etc. he used would be useful too?

 

[Jacob]

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).

 

[John Brown]

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...