SammyBar wrote:

Yesterday I tried to put the new melamine countertop (Kober) to my kitchen
with awful results: I should buy a new one and redo everything. The
principal problem was to cut the 45degree to make the two pieces to meet in
the vertice of the "L" I could not make the two pieces to join in an
acceptable (not only for my wife but for myself) way.

snip

Any suggestion for well doing this job is welcomed.

First, have you checked that the walls actually meet at a 90 degree
angle? You might want to verify that first.

As for the cut itself...maybe just pay a custom countertop place to cut
it for you?

Chris