To be fair, after he is used to his kit and confident in it's accuracy, he will settle into using it all without the need to check.... we all want to achieve perfection ( or at least look like it )
What have I done wrong? Carcass not square
- Thread starter Mjward
- Start date
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Samkilby
Established Member
Yeah this happens.
Even if the boards and corners are square, long runs will âbellyâ one way or the other. In commercial world the usual âfixâ is to either pull it up when fixing to the wall, or use overlay drawer fronts and doors (which will mask as much as possible any issues with the aperture)
The point of the back panel is in addition to providing structure, to pull the carcasse out of rack, so something sturdy (12mm+) can be preferable as you can get proper screws through it.
You can pin the back on, but probably better if the corner joints are dowelled or similar in addition to screwed.
If you are worried about structure you can pu glue the corners, but tape up the joints first whilst the cabinet is still together and use less than you think as it foams up a lot.
In the commercial world you donât usually measure the square of the corners because of exactly this issue. A tape measure over the outside corners is usually sufficient.
Ta
Even if the boards and corners are square, long runs will âbellyâ one way or the other. In commercial world the usual âfixâ is to either pull it up when fixing to the wall, or use overlay drawer fronts and doors (which will mask as much as possible any issues with the aperture)
The point of the back panel is in addition to providing structure, to pull the carcasse out of rack, so something sturdy (12mm+) can be preferable as you can get proper screws through it.
You can pin the back on, but probably better if the corner joints are dowelled or similar in addition to screwed.
If you are worried about structure you can pu glue the corners, but tape up the joints first whilst the cabinet is still together and use less than you think as it foams up a lot.
In the commercial world you donât usually measure the square of the corners because of exactly this issue. A tape measure over the outside corners is usually sufficient.
Ta
Although this will have a face frame and overlay drawer fronts that would let me get away with it, its this very early stage in my woodworking adventure I am very keen to form good habits and also learn how to fix mistakes (as I am sure there will be a few along the way). I am using 12mm back panels and pins but didn't think to screw it as was under the impression the core of MDF (i.e. what it would be hitting in the carcass) is for want of a better word "mush". Going to try the dowel/glue and screw approach today and see how I fare (vs pocket holes)
Samkilby
Established Member
I think if the face frame is sturdy, and sturdily attached with something that will reference it to flat (ie biscuits or dowels etc) on the face of the carcasse then it will likely pull it straight. If you cut a bit of mdf the same size and thickness as the carcasse uprights, the middle will flex as it doesnât have the structural ridgidity to not do. So if we remove the issue of not square corners (which having a very squarely cut back panel, and then flexing the carcasse to fit it when attaching it will fix the problem at the back edge) then the front will still belly in the centre of the run.
The face frame will fix this.
Other option is to build out of thicker material, or something sturdier like birch ply..
doweling the corners of the carcasse may help with the squareness of the corners, but wonât fix the bellied carcasse sides.
In your standard kitchen this is mitigated by jamming lots of units next to each other and fixing them off to each other (pulling them up)
With regards the back panel, clearance holes through the mud back panel, and holes exactly the diameter of the shank of the screw (not the size of the thread) will work fine, you could use pan head screws if you donât want to countersink.
I would personally start with the back panel, measure it as accurately as you can corner to corner, then itâs width at the top and at the bottom. If thatâs all fine, does it allign perfectly everywhere with the carcasse ? If not, take it off, and when attaching it again flex the carcasse ( or use clamps as spreaders) to allign it as well as you can, then the back of the carcasse will be pulled square. Start in one corner, then work along one edge, then the next edge.
Hope this helps.
The face frame will fix this.
Other option is to build out of thicker material, or something sturdier like birch ply..
doweling the corners of the carcasse may help with the squareness of the corners, but wonât fix the bellied carcasse sides.
In your standard kitchen this is mitigated by jamming lots of units next to each other and fixing them off to each other (pulling them up)
With regards the back panel, clearance holes through the mud back panel, and holes exactly the diameter of the shank of the screw (not the size of the thread) will work fine, you could use pan head screws if you donât want to countersink.
I would personally start with the back panel, measure it as accurately as you can corner to corner, then itâs width at the top and at the bottom. If thatâs all fine, does it allign perfectly everywhere with the carcasse ? If not, take it off, and when attaching it again flex the carcasse ( or use clamps as spreaders) to allign it as well as you can, then the back of the carcasse will be pulled square. Start in one corner, then work along one edge, then the next edge.
Hope this helps.
TomGW
Established Member
Go to an art/graphics supply shop that sells draftsmanâs equipment and buy set squares in a selection of sizes. Theyâre cheap and accurate, perfect for building cabinets and for setting up perpendicular cuts with a track saw. I think my largest is 600mmx600mm. Invaluable for checking wall corners when trimming a worktop to fit in a recess.
