When we setup the Tongue and Groove, and
value we use in the “Tongue Thickness” it will make the Groove position move
further away from the edge, below is a detailed breakdown to what is happening
and why it was set that way.
1) With the tongue the same size as the groove (ie 0mm
undersized thickness).
G+B=D
G=T
B=A
this
can make the fit a little tight (that is why the default undersize is 1mm).
3) With the tongue reduced in thickness (by X) and the groove also
moved inwards by X.
G+B1=D+X
G-X=T1
B1=A1
The objective is that the Bottom
faces (green) line
up.
Theoretically, both (2) and (3) can succeed
depending on the position of the tongue within the groove.
i.e. In (2) the blue faces touch and in (3) the orange faces touch.
But, we are dealing with board that is not always the thickness it is
advertised to be (eg 16mm board is usually at least 16.1mm).
Therefore, depending on the z-zero (‘Top or
Bottom of Plate’ in EnRoute terms) when on the flatbed, the thickness of the
Tongue (T1) or the gap A1 could be larger than anticipated.
With
‘Top of plate’, T1 will larger by the extra thickness of the material.
With ‘Bottom of plate’ A1 will larger by the extra
thickness of the material.
Either case will make (3) the only viable option.
Example:
Settings:
board thickness
(D) = 16mm;
groove width (G)
= 9mm;
tongue thickness
reduced by 2mm;
then
A1=D-9+2=9mm;
and T1=D-A1=7mm.
Reality 1:
board thickness
= 16.2mm;
‘Top of Plate’
in use;
CabMaster still
calculates A1=9mm;
‘actual’ A1=9mm;
‘actual’
T1=16.2-9=7.2mm.
So, using (2) above the green faces will not line
up because D>G+B .
But, using (3) above (with the orange faces touching) the green faces will line up (as A1
will always equal B1).
Reality 2:
board thickness
= 16.2mm;
‘Bottom of
Plate’ in use;
CabMaster still
calculates A1=9mm;
‘actual’ A1
=16.2-7=9.2mm;
‘actual’ T1=7mm.
So, using (2) above the green faces will not line
up because D>G+B .
But,
using (3) above (with a gap of [‘actual’ A1]-A1 between the orange faces)
the green faces will line up (as long as the thickness reduction X >= the
difference between the actual and specified material thickness, otherwise the
tongue is too big; i.e. X>=[‘actual’ A1]-A1).
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