Is this 3D model free to download?

Yes, Prusa i3 MK3 X carriage back plate with belt access is free to download from Thingiverse. Open it in the free Thinger app, or use the "Download from Thingiverse" link to open the original listing by the creator.

Where do I download the STL file?

The download is hosted by Thingiverse. Use the "Download from Thingiverse" link on this page to open the original listing and grab the file, or save it to your print queue in the free Thinger app.

Designed by jltx, published on Thingiverse. Please credit the creator when sharing your print.

Can I print this at home?

Yes. This is a printable 3D model intended for home FDM and resin printers. Check the original listing for suggested print settings.

Prusa i3 MK3 X carriage back plate with belt access

Source: Thingiverse by jltx

The Prusa i3 MK3 X carriage back plate with belt access is a free printable 3D model from Thingiverse by jltx. I don't understand why they made belt maintenance so hard on MK3. You can download the STL file from the original listing below and print it at home.

Open in Thinger (free) Download from Thingiverse

43 saves Source: Thingiverse Updated 2026-10-08

Tags: Prusa, i3, MK3, X, carriage, back, plate, with, belt, access

About this model

I don't understand why they made belt maintenance so hard on MK3. So I made a version that allows access to the belt clamps but is just as rigid. I started with the original Prusa design. If you are able, you should print this upgrade before you first assemble your MK3. Retro-fitting will make you cry. See (thanks Mat1UK) I printed versions in both ABS and PETG and they came out great. I printed with 0.35mm layer just like stock parts. I used the out-of-the-box settings in slic3r, but added 0.3mm elephant foot compensation which helps the screw holes and channel. 2/12/18 Update Prusa released R2 versions and I updated the back cover to give belt access. Need to flip over before slicing.

Frequently asked questions

Is this 3D model free to download?: Yes. Prusa i3 MK3 X carriage back plate with belt access is free to download from Thingiverse. Open it in the free Thinger app, or use the "Download from Thingiverse" link above to open the original listing.
Where is the STL hosted?: The download is hosted by Thingiverse, not by Thinger. We link you directly to the original listing by jltx.
Who made this model?: Designed by jltx, published on Thingiverse. Please credit the creator when sharing your print online.
Can I print this at home?: Yes. This model is intended for home FDM and resin 3D printers. Check the original listing for suggested print settings like layer height and supports.