Building cabinets square

[Prizen]

Hi All

Another beginner question. I have attempted to make a cabinet carcass but haven't been able to keep it square after assembly.

I used 12mm plywood, and 6mm dowels for the joinery. The dimensions of the cabinet are quite large, somewhat larger than typical kitchen base cabinet, at approx 600mm tall, 750mm wide, and 600mm deep.

Through rushing and being a little blinkered, I assumed that the joinery (dowels, qty:6 per edge) would ensure all was square, but this turned out not to be the case.

I'm thinking that I should have probably made more dowel joins.

I also wonder if rabbet joint would tend to a square assembly more than dowels would?

Or should I build some clamping squares and just glue & screw butt joints.

My tools relevant to this build are: Track Saw, Router, Dowel jig. Have no pocket hole system.

thanks

 

[Doug71]

Use whatever method you want to make the cabinet. Once it is glued and screwed or cramped together check the diagonal measurements from corner to corner are the same, when it's adjusted so that they are screw a lath temporarily across the back at 45 degrees (ish) to tie one of the sides to the top or bottom, this will hold it square until the glue has set. Putting a nice square back on after will help hold everything square.

 

[transatlantic]

Do you mean it didn't end up square because the joinery was off? or because the glue dried with it in a twist?

If it's the latter, you could try something like this :

 

[johnnyb]

squareness of cabinets is a universal problem. corner to corner checking is the way to check. get it right then brace using the back or something.
as cabinets go bigger that may not be enough what happens is the doors wont fit correctly. the big floppy tall kitchen cabs are terrible to get square and level.

 

[will1983]

Prizen,

Getting cabinets square all starts at the beginning, if you observe these steps you should end up with a square box

Initially you have to make sure that all the individual parts you are cutting out are square themselves, wonky parts will make a wonky box.
Each of the parts should be flat, bowed sides will pull things out of true.
The reference edges of your panels need to be square to their faces for your doweling jig to seat correctly and ensure that the panels will meet correctly with flush corners.
Using dowels and a doweling jig (insert joining method of you choice here, biscuits, dominos, loose tenons, housing/rebate joints etc) will not pull a cabinet into square, all it does is line up the components correctly and provide a bit more gluing area. You have to check square and adjust with either nailing on a cabinet back or clamping on the diagonal.
That being said, poorly fitting joinery will actually do more harm than simple butt and screwed joints so use it carefully.

 

[deema]

You don’t mention the back of the cabinet. This is what keeps the unit square and true. The joints on any large cabinet won’t keep it square, just together. You either have a slide in back, attached directly to the back or housed back. It all depends on whether the back
will be seen / utilities passing behind.

I suspect if you cut a square and true back and add it, your perceived problems will be resolved.