Bernard,

Think about it... The table top (miter slots) are not parallel to the
blade - hence the distance from a point on the front of the blade and a
reference point on the miter gauge head will be more/less as the miter
gauge
is moved to the rear of the blade. Do you need a drawing to visualize it
?
ASCII art below is exaggerated but shows what I mean. As the Ref point
moves towards the rear of the blade the distance from Ref point to the
blade
is less. Now if the miter gauge head is not perpendicular to the slot,
that
introduces even more error as well and if the slot is not perpendicular to
the table edge - more error is introduced.


Yes...HOWEVER, this has nothing to do with the angle of the miter
GAUGE...not the miter SLOT.

The angle of the miter gauge doesn't matter for checking the blade to the
slots for the same reason that you can actually cut a miter with said gauge
after the table is aligned to the slot.

Mike