CoreOne Filament Bay Door

Hinged magnetic door for the filament bay of the Prusa Core One.

Based on the original Filament Hatch, this version adds three integrated hinges, allowing access without fully removing the cover. The door closes flush and is held in place using continuous magnetic tape for even contact pressure.

A 3 mm acrylic panel is integrated into a modular printed frame assembled with M4 screws and heated inserts. All parts are rear-labeled for orientation. Optional hygrometers can be installed.

The door and frame use the same M4 threaded inserts as the original hatch design.
The three hinges are mounted using M3 hardware.

Compatible with Core One and Core One+, including setups with the extended filament holder.
All parts print without supports.

Note: the Core One ships with zero heated inserts — this version increases the total to thirteen.

Required Hardware

• 10× M4 heated inserts (4 mm OD)

• 10× M4×15 mm slotted screws

• 3 mm acrylic sheet, 328 × 326 mm

• Magnetic tape, 13 mm wide, 1.8 mm thick

• 3× M3 heated inserts (installed in door)

• 3× M3×5 mm countersunk screws

• 3× M3×10 mm countersunk screws

• 3× M3 washers

• 3× M3 nuts

• 3x M3x25 Allen screw

Printing instructions

Each printed part is required only once. Lowercase part names indicate side components, while parts starting with an uppercase letter are used for the top and bottom sections.

Hinges are named after the frame part to which they are attached.

Acrylic glass

*measurements in mm

Assembly

The frame construction is the same as for the CoreOne Hatch, but the right side has no handle and has recesses for the hinges.

The front inlets for the threaded inserts are angled so that precise insertion with a soldering iron should be easy. Afterwards, the frame parts are most easily mounted on the acrylic glass. This works without adhesive. If the glass vibrates in the frame, a little adhesive would be appropriate. Once the frame has been mounted on the glass, the magnetic tape can be stuck into the gap in the frame.

Unlike the hatch, no magnetic tape needs to be attached to the right side of this project, as that is where the hinges will be located.

The hinges are not yet attached to the frame.

The hinges are assembled by connecting the door piece and the CoreOne piece with an M3x25 Allen screw as the axis. On the side with the recess for the head, the screw should be easy to insert and then screwed into the hole in the other part of the plastic. Do not tighten too much here, as the hinge still needs to be able to move.

Mounting on the CoreOne

To install the hinges on the CoreOne, the nylon rivets must be removed. I was able to remove them easily by hand, but there are several devices available on printables for this process.

Make sure that the lower hinge is mounted “upside down.” Use the M3x10mm countersunk screws to mount the hinges. On the inside, you need to use a washer and nut to secure the screw (or just a nut, it's your build).

It's a bit fiddly, as the nuts have to be fitted blind.

If the hinges are not yet tightened securely to the CoreOne, adjustments can still be made during door installation.

Then you can attach the door to the hinges using the m3x5mm countersunk screws. Screw the screws through the hinges into the heated inserts in the door.