Build a desktop letter sorter with two pockets

Choose a useful paper orientation

A letter sorter should make papers visible without encouraging an unstable pile. This concept stores ordinary envelopes on their long edges in two shallow pockets. It is not intended for heavy books or tall stacks of files. Measure a typical envelope before setting the width.

The example uses a 270 × 140 mm base and three upright panels. The back and middle panels are taller than the front, creating a stepped view of the contents. Use flat plywood so the panels do not pinch the pockets.

• Base: 270 × 140 × 9 mm.
• Back: 270 × 140 × 9 mm.
• Middle: 270 × 110 × 9 mm.
• Front: 270 × 70 × 9 mm.
• Two end cheeks: 140 × 70 × 9 mm, optional after fit testing.

Calculate the pocket depths

Place the back upright flush with the rear edge of the base and the front flush with the front edge. Their combined thickness leaves 122 mm between them. A 9 mm middle panel uses part of that space, leaving 113 mm for the two pockets. One practical split is 55 and 58 mm.

Mark the two faces of the middle panel on the base. Keep the pockets modest so paper stands visibly rather than sinking into a deep bin. If adding end cheeks, fit them outside the panel ends or revise the width; do not accidentally shorten the pockets by inserting unaccounted-for thicknesses.

Hold the panels parallel

Sand all inward-facing surfaces before assembly. Glue the back and front first, checking their angle to the base. After they cure, fit the middle panel using temporary spacer blocks cut to the chosen pocket depths. Keep the spacers clear of squeeze-out.

A middle panel that leans can make one pocket narrow at the top and wide at the bottom. Check the distance between panels at both heights. Small reinforcing blocks near the ends of the panels can improve the glue area, but position them where envelopes will not catch on them.

Evaluate visibility and access

Load a few envelopes, then view the sorter from your usual position. Labels such as “to act on” and “to file” can be more useful than vague categories, but keep the labels removable while you learn your routine.

Ease every upper corner, since hands pass close to them during retrieval. Lift the sorter by its base rather than a thin divider. If the full sorter tips when one pocket is emptied, reduce the paper height or increase the base depth in a revised version. A tidy appearance is not evidence of stability.