MX Mechanical Key Guard

What this is

A keyguard overlay for the Logitech MX Mechanical keyboard, designed for people with limited dexterity — including tremor, reduced fine motor control, or conditions like arthritis or cerebral palsy — who need help targeting individual keys accurately without triggering neighboring ones.

The guard sits directly over the keyboard with a hole positioned over each key. Holes are sized so a fingertip, knuckle, or stylus can reliably reach the intended key while the surrounding 5 mm plate blocks accidental presses on adjacent keys and lets a user rest their hand on the guard's surface without pressing anything underneath. A full perimeter skirt follows the shape of the keyboard case, registering the guard in place over the keys while adding rigidity to the plate.

Two versions are included — pick whichever suits your printer:

• Single-piece (uncut) — the full ~434 mm × 123 mm guard as one part. Simpler: no hardware, no assembly. Requires a printer with a build plate large enough to fit it in one piece.

• Three-piece (Left / Center / Right) — the same design split at the board's natural gaps into a Left half, a Right half, and a smaller Center piece that bridges the two, sized to fit a standard consumer print bed. The Center piece carries locating notches that the Left and Right pieces key into, keeping all three aligned before final assembly (below).

Both versions share identical hole geometry, mounting skirt, and print orientation — the only difference is whether the plate is one part or joined by you after printing.

Design details

• Plate thickness: 5 mm — provides standoff height above the keys and blocks accidental presses

• Hole sizing: 15 mm width, length varies per key (stadium-shaped for elongated keys like Shift, Enter, and Spacebar) to match the actual key footprint

• Mounting: a full perimeter skirt follows the keyboard case's taper, registering flush against the case body (not the keycaps) with roughly 1 mm clearance for easy on/off, and reinforcing the plate's rigidity

• Piece joints (3-piece version): the Center piece has locating notches that the Left and Right pieces fit into, keeping all three sections aligned; secured with M3 screws and captive nuts at each seam

• Print orientation: upside-down, so the guard prints support-free on both versions — support material needed only for the locators

• Material: PETG recommended (better resistance to warping on a large flat part, and more durable under repeated removal/reinstallation than PLA)

What you'll need

Single-piece version:

• The printed guard — no additional hardware required

• Optional: removable, no-residue double-sided tape (e.g. Command strips) for extra hold

Three-piece version:

• The three printed pieces (Left, Center, Right)

• 4× M3 screws (10–10 mm length)

• 4× M3 hex nuts

• Optional: removable, no-residue double-sided tape for extra hold

Assembly instructions

Single-piece version:

1. Print the guard in the orientation provided (upside-down) — no supports required.

2. Place it over the keyboard, aligning the perimeter skirt against the case edge. It should seat by hand with a light press.

3. (Optional) Apply small pads of removable double-sided tape between the guard's underside and the keyboard case for a firmer hold.

Three-piece version:

1. Print all three pieces in the orientation provided (upside-down) — no supports required.

2. Fit the Left piece into the Center piece's locating notch on that side, and the Right piece into the notch on the opposite side. The pieces should register into place by hand, with holes lining up across each seam.

3. Insert an M3 screw through the clearance hole at each of the two reinforced points where a seam crosses the outer skirt (one at the Left–Center seam, one at the Center–Right seam).

4. Thread each screw into the captive hex nut pressed into the mating piece's nut pocket, and tighten by hand until snug — don't overtighten, as this only needs to resist separation, not clamp with heavy force.

5. Repeat for the second seam (4 screw/nut sets total across both seams).

6. Place the assembled guard over the keyboard, aligning the perimeter skirt against the case edge. It should seat by hand with a light press.

7. (Optional) Apply small pads of removable double-sided tape for a firmer hold.

Who this helps

Designed for anyone who finds precise key-targeting difficult — tremor, limited fine motor control, arthritis, or similar conditions affecting hand dexterity. The plate's thickness lets users rest their hand on the guard without accidentally pressing keys underneath.