diff --git a/enclosure/lib/params.scad b/enclosure/lib/params.scad
index 4656a0f..83a7e2b 100644
--- a/enclosure/lib/params.scad
+++ b/enclosure/lib/params.scad
@@ -53,7 +53,7 @@ plunger_tip_d     = 3;                                         // tapered tip 
 // has ~0.4 mm of travel — the extra length is taken up by the cap
 // floating slightly higher than its theoretical rest position, not
 // by depressing the switch.
-plunger_preload = 2.3;
+plunger_preload = 3.3;
 
 // ============================================================
 // MAX98357A I2S amp breakout
@@ -176,13 +176,16 @@ z_atom_center       = (z_atom_bottom + z_atom_top) / 2;     // 108.4 — USB-C p
 // Snooze cap geometry — "top hat" button, install from below.
 //
 // Top to bottom in normal orientation:
-//   - Crown (15 mm OD) — visible above the disc top, sticks up
-//     through the 16 mm central hole.
+//   - Crown (15.7 mm OD) — friction fit in the 16 mm central hole
+//     (0.15 mm radial clearance, snug PLA-on-PLA sliding fit). 8 mm
+//     total height: 4 mm engaged inside the disc rim, 4 mm visible
+//     above the disc at rest.
 //   - Flange (22 mm OD, 2 mm thick) — captures the cap from below
 //     by catching on the disc's underside at rest.
 //   - Plunger (8 mm base, 3 mm tip, tapered) — extends from the
 //     flange's underside down to the Atom button. Offset from the
-//     cap's center to land over the Atom's button cap.
+//     cap's center to land over the Atom's button cap. Tapered side
+//     wall + friction-fit crown together resist cap tilt in the hole.
 //
 // Cap installs from below: pushed up through the cavity (before the
 // protoboard is mounted) so the crown emerges through the central
@@ -192,17 +195,17 @@ z_atom_center       = (z_atom_bottom + z_atom_top) / 2;     // 108.4 — USB-C p
 // disc's underside. Cap mass is ~3 g — easily lifted by the spring.
 //
 // Print orientation: cap upside-down with the flat crown top on the
-// build plate. Going up in the print: crown (15 OD) → step out to
-// flange (22 OD, single-layer 3.5 mm bridge — PLA handles cleanly)
+// build plate. Going up in the print: crown (15.7 OD) → step out to
+// flange (22 OD, single-layer 3.15 mm bridge — PLA handles cleanly)
 // → step in to plunger (8 OD, offset on the flange) → tapered tip
 // (3 OD). All transitions inward except the small crown→flange step.
 // ============================================================
 
-snooze_cap_clearance = 0.5;        // radial clearance between crown and disc hole
+snooze_cap_clearance = 0.15;       // radial clearance — snug friction fit in the disc hole
 snooze_cap_travel    = 1.5;        // geometric max — actual is ~0.4 mm (Atom switch travel)
-snooze_cap_h_above   = 2;          // crown sticks this far above the disc at rest
+snooze_cap_h_above   = 4;          // crown sticks this far above the disc at rest
 
-crown_d = top_hole_d - 2 * snooze_cap_clearance;        // 15 — slip fit in the disc hole
+crown_d = top_hole_d - 2 * snooze_cap_clearance;        // 15.7 — friction fit in the disc hole
 flange_d = 22;                                           // wider than top_hole_d, much narrower than cylinder ID
 flange_h = 2;
 
diff --git a/enclosure/parts/snooze-cap.scad b/enclosure/parts/snooze-cap.scad
index 5df17ea..a12532a 100644
--- a/enclosure/parts/snooze-cap.scad
+++ b/enclosure/parts/snooze-cap.scad
@@ -4,24 +4,26 @@
 // the flange sits in the cavity below the disc's underside.
 //
 // Top to bottom in normal orientation:
-//   - Crown: 15 mm cylinder. Sticks up through the 16 mm hole in the
-//     disc top and protrudes 2 mm above at rest.
+//   - Crown: 15.7 mm cylinder — friction fit in the 16 mm disc hole
+//     (0.15 mm radial clearance). 8 mm total: 4 mm engaged in the
+//     disc rim, 4 mm visible above the disc at rest.
 //   - Flange: 22 mm disc, 2 mm thick. At rest, the flange's top face
 //     touches the disc's underside (held there by the Atom button's
 //     spring pushing on the plunger from below).
-//   - Plunger: 8 mm tapering to 3 mm tip, 5.5 mm long. Offset from
+//   - Plunger: 8 mm tapering to 3 mm tip, 6.5 mm long. Offset from
 //     the cap's center to (button_offset_x, button_offset_y) so it
 //     lands precisely on the Atom's button cap. The plunger extends
-//     plunger_preload (2.3 mm) past the nominal z_atom_top: real
+//     plunger_preload (3.3 mm) past the nominal z_atom_top: real
 //     stack-up runs short of the math (pin headers seat shorter than
 //     6 mm, etc.), and this preload ensures firm contact with the
-//     cap at its rest position.
+//     cap at its rest position. The tapered side wall + friction-fit
+//     crown together resist cap tilt in the hole.
 //
 // Mass ~3 g. Atom button's ~50 g spring lifts it easily.
 //
 // Print orientation: cap upside-down with the flat top of the crown
-// on the build plate. Going up: crown (15 OD) → step out to flange
-// (22 OD, single-layer 3.5 mm bridge — clean PLA bridge) → step in
+// on the build plate. Going up: crown (15.7 OD) → step out to flange
+// (22 OD, single-layer 3.15 mm bridge — clean PLA bridge) → step in
 // to plunger (8 OD, offset on the flange's top in print) → tapering
 // down to the 3 mm tip. All transitions inward except the small
 // crown→flange step. No supports.