A 2x4, when it comes from the mill is 3-1/2" wide and 1-1/2" thick and has slightly rounded corners.   For this project I'll plane about 1/16" off each board face so the 2x has nice square corners (See Square Board Page for more info) and the joints will be flush.   The resultant 2x4s will be 3-3/8" by 1-3/8".   The bench top is made from 2x6s edge laminated so I end up with a 1-1/2" thick top, 18" wide and 36" long.   All joints use biscuits every 4 inches on the center line of the boards being joined.   You have to keep everything square and plumb so drawers work.   Passing the 2x4s across the jointer I still hold the 10" from the end dimension of the right vertical support so the loading bay is 10" deep.   Planing with a jointer makes the drawers about 1/4" wider.   I take 1/16" off each side (2 cuts of 1/32" off each side), reducing the width and thickness by 1/8", so I have to increase the lengths of the horizontal braces in the vertical frame pieces by 1/4" to compensate.  

Drawers are 5" high, 16" deep, and 26 1/8" wide to fit into a 26 1/4" wide space.   The drawer front is a 1x6 cut down to 5" high, 26 1/8" wide with a 1/2" rabbet on each end to conceal the slides.   The sides and back are 1x4s resawn and joined on the sawn side leaving about 5/16" thick and sides are 16" long, back is 26 1/8" wide.   I allow 1/16" on each side of a drawer, and at least 1/8" vertical clearance between drawers, and top drawer and frame.   If you are not careful with measurements and cutting, you may want to allow more clearance for the drawers.   I always put the guide 1" from the bottom of the drawer, so, since each drawer is 5" high, I measure down 4 1/8" from the top, draw a horizontal line and mount the cabinet side of the drawer guide on this center line.   Then another 5 1/8" down to the next drawer guide center line (and any additional drawers I add).
Here is a link to how I make drawers and handles

The loading shelf and the vertical frame for it is made from 1/2" plywood, usually birch.   Loading shelf and slide diagram.

Diagrams

All these diagrams are .png format, you can save them on your computer then display with Firefox and print them.   Or click on the image for a single page with the image on it.

Front of the bench.   The main bay is on the left, facing front, and has drawers in the top, the loading bay is on the right end, opening to the right, and has the loading shelf.   Click on the image for a single page with the image on it.

Right (loading bay) end.   Click on the image for a single page with the image on it.

Left, Center, and Right End Frame Pieces.   Click on the image for a single page with the image on it.

Bottom Frame Piece (Stringers).   Click on the image for a single page with the image on it.

Wooden slide for the loading shelf.   Note the slot is shown as 1/2", normally plywood is 1/32" thinner than it's nominal thickness.   In a recent loading shelf, the plywood was exactly 1/2" thick and I had to make this slot 9/16" but still centered in the guide.   I have also replaced the front pull block with a front piece that is same width as the shelf, covers the front and extends below to form a lip as a pull.   Click on the image for a single page with the image on it.

Slots for panels and floor.   The inset panels go on the inside of the main bay and inside the front and back verticals for the loading bay.   The panels are 1/2" plywood, I cut the slots 1/2"/ X 1/2".   You can use most any thickness of plywood for the floor, I use 1/4".   The floor brace in the center of the front bay must be recessed 1/4" to match the bottom of the floor rabbet (see detail at lower left).   Click on the image for a single page with the image on it.