Frameless Box Tolerances: Decks Versus Gables

Is it worth cutting tops and decks just a hair shy, so as to avoid revealing end wood in case of inaccuracy? March 13, 2014

Question (WOODWEB Member) :
We have always made our upper tops and decks 1/32 narrower front and back than the gables. This was so that if it was off we would not see any raw wood. We build a frameless cabinet and assemble with dowels. Now we have a CNC and can have sizes exact. I am not sure if there is any merit in the little oddity of cutting the tops and decks smaller rather than being confident that these can be the same size as the gables and fit fine every time? I wonder if cutting undersize is a still a good practice, now that we have a nester that can cut accurately. Up until now we have used slider and a point to point.

From contributor G:
We use .5 mm and I think it is worth doing. As you say it just insures you don't show raw board. We are using a CNC and a horizontal drill.

From contributor D:
I started doing that years ago too, .5mm front to back to hide slight discrepancies. I continue even now with CNC to allow for radius on edge-banding. We use 1mm band with an eased edge so .5mm is just the right amount to allow for this without gap at panel joint.

From the original questioner:
Thanks for your replies, this is such a great resource. This leads to another question. We dado our backs into the cabinet on four sides but have always referenced from the front edge of the gable on the ptp for construction holes and dadoes. This would put any error to the back. I think we can start to reference from the back of gable now on the nester. Any thoughts on this?

From Contributor B:

I only have one particular thought on this - if the way you did things before worked, do you have any need to change things now?

From the original questioner:
Good question. Our Biesse rover 20 saw could not reach to the back of a 23 5/8 base gable when the front edge was at the stops. So our base backs where recessed another 1/8" we would like to put the dado back where it should be so all uppers and bases have a common dado position from the back. We build a kitchen every day and are trying for simplicity.

From Contributor B:
In that case it sounds like a good idea - to my mind simplicity plus standardization equals profitability.