Mount the Drawer Slides First, Then Build the Drawer Box in Place

The Problem

The usual drawer sequence — build the box, then mount it to slides — stacks every small error into the final fit: the box is a sixteenth wide at the back, the slides end up a hair out of parallel, and the drawer binds. Aligning slides to a bulky finished box is the fight; this sequence removes it.

The Technique

1. Set a thin spacer in the cabinet for the drawer's bottom clearance, then a second spacer on top of it to position the slide — the spacers register everything, no level needed.
2. Mount the slides to the cabinet on the spacer.
3. Mount just the drawer sides — two loose panels — to the slides. For inset fronts, set them flush with the drawer boxes below.
4. Measure the exact distance between the two mounted side panels. Front to back it can vary by a sixteenth; measure where it matters.
5. Cut the front and back to that measurement and attach them with pocket holes and screws — the pocket holes land where the drawer front will hide them. Then remove the spacers and carefully take the three-sided assembly out.
6. Finish the box: cut grooves in the pieces on the table saw, size the plywood bottom to seat into all the grooves, run glue in the grooves, and slide the bottom in. Extra grooves in the sides make room for a divider if you want one.
7. Slide the finished box onto the already-mounted slides. They're perfectly placed — because the box was dimensioned by them.