Cut 2 strips of mat board 5-7/8" x 1-7/8". (I know my strips are wider than 1-7/8".) Glue them together.
Center this piece under the cabinet front, leave a 1/16" space at each side. The bottoms should be even.
Trace the toe kick area.
Cut the toe kick out.
Oh my, look at that messy cut!
Glue this piece, the big piece, to the back side of the cabinet base front. Center this so that there is a 1/16" space at each side and bottom is even. When we glue the toe kick's back in it will have some realistic depth to it. We won't be cutting and gluing the toe kick's back in until we get to the finishing of the cabinet.
1-11/16" is what I'm going to cut the width of the side. That leaves a 1/16" past the post for the lip of the counter top.
Cut 2 at 2-7/8" x 1-11/16"
Glue the sides onto the cabinet front. The cut edge of the front shows on the sides. You don't glue onto the cut edge of the front.
The piece we glued to the front makes a nice "L" shape for the sides to be glued into.
For stabilization I want you cut some triangles to glue into the corners of the cabinet.
If you have a square, use it.
Glue the triangles into the cabinet base.
Glue the top ones level with the front and sides.
Glue the bottom triangles about a 1/4" up from the top of the toe kick.
For the back we need to cut a piece 2-7/8" x 5-7/8".
Before gluing into the cabinet base measure 7/8" down from the top, one long side. Draw a line. Cut a strip of mat board about 1/4" wide and about 3" long. Glue this right under the line you drew in the center of the back.
Now, glue the back into the cabinet base between the sides.
Here's the back glued in with that strip glued in.
Cut more triangles and glue them into the cabinet base.
Cut a piece of mat board 1-5/8" x 3". This is the shelf the sink sits on.
Glue this into the cabinet base.
The cabinet base is done, onto the sink.