June 2, 2026
Description
This is a practical, printed 608 Bearing suitable for many DIY projects (for example in a spool holder).
It is a fully functional roller bearing with a proper working cage.
It runs like a real bearing with a smooth action, tight fit & low friction.
It has virtually no radial play, providing a predictable axle position in any assembly.
It is a configurable assembled bearing, superior to print-in-place designs (and bushings).
It is 100% printed, no hardware required.
It is suitable for any regular 3D printer, and with straightforward assembly.
PLA recommended
Print the parts separately and then assemble them.
Print with 0.4 mm nozzle at 0.15 mm layer height
Random scarf joints on contours & inner perimeters
Control/check the rollers for elephant foot
Assemble the parts in sequence; Outer Race --> Inner Race --> Cage --> Rollers (with needle nose pliers) --> snap on Outer Cap snap --> snap on Inner Cap
This assembled bearing is more practical than Print-in-Place designs (or Bushings):
It has tighter fits, since it doesn't require printing clearances (unlike PIP).
You can inspect & finish the running surfaces if needed.
You can use different materials for the rollers (including FLEX!).
You can optimize the rollers fit for your application, balancing tightness and friction. Different size rollers are included in the STL files.
Drop-in fit for any light 608 bearing application.
Not intended for high velocity/force/heat applications; use a normal, purchased 608 bearing for that.
It can handle decent lateral loads.
The hollow rollers provide a little bit of elasticity; more traditional solid rollers are also available.
Semi-enclosed back, with an option for a semi-enclosed front side (to keep lubricant in and/or dirt out)
Print the parts separately and then assemble them together.
The "All Parts - Print Layout" STL file is ready to print. It has all the parts in print orientation, with one extra roller (as a backup). The rollers are the "Solid Loose" variant and should work for most. If it is a bit loose try a tighter Roller, see below.
There are individual STL files to configure the bearing to your liking and application:
Outer Race, Inner Race & Cage are always the same.
Outer and Inner Cap in Regular (Open) and Semi-enclosed variants.
Rollers
Solid & Hollow variants
Three sizes: Standard, Tight & Loose. You can also XY scale the rollers in the slicer to optimize fit.
For Races, Caps & Cage: PLA recommended, other materials should work but haven't tested it
For the Rollers:
PLA works well, it can be a bit noisy
PETG is a great choice, it provides a nicer feel and prevents binding over time under load.
FLEX/TPU also works! (best in Solid rollers). It makes the bearing dead quiet while it still runs, with a bit more friction. Great option if you need a very quiet bearing.
0.4 mm nozzle
0.15 mm layer height
2 perimeters, 15% infill
Print orientation as shown in the All Parts STL file:
No supports needed.
The Races, Cage and Roller STLs are oriented correctly by default.
Both individual Cap STLs should be re-oriented onto the flanges.
Key (Prusa)slicer settings that worked best:
Random seam position
Scarf joint on Contours (except the Rollers if printing those separately)
Scarf joint on Inner Perimeters
Check/control for elephant foot, especially the Rollers. I print a 1 or 2 extra, in case one looks worse.
18 minute print time on a Prusa Mini or Mk4 if printed all parts at once.
The 3MF files are primarily for illustration but they can be imported into a slicer. They should not be printed as is, this design is not Print-in-Place. When importing the 3MF file rearrange the individual parts in the slicer.
Check the roller running surfaces on the inner and outer race for bumps/printing artifacts. You can run a small file on both roller running surfaces to take off any artifacts and smoothen the surfaces if needed.
Note that the Caps and Races look somewhat similar:
The Outer Race has a slightly smaller diameter than the Outer Cap.
The Inner Race has a slightly larger diameter than the Inner Cap.
Place the Inner Race & Outer Race down (see the note above on telling the difference from the Caps)
Place the Cage, with the ring down.
Place 7 Rollers (small needle nose pliers work well).
Place & snap the Outer Cap on the bearing assembly.
Place & snap the Inner Cap on the bearing assembly.
Check that the Caps are fully seated and flush with the Races. The back of the Bearing should look like the picture in Step 6.
Do not lift the assembly before both Caps are snapped in place! The bearing will fall apart, and the rollers will go everywhere. You can place the Inner and Outer Race on a piece of painter's tape to keep them together during assembly.
Lubrication is optional, it is not needed but makes the bearing run a little nicer. Consider Semi-enclosed Caps to keep the lubricant in.
Step 1 Step 3 Step 3 complete Step 4 & 5 Step 6
Exercise the bearing a few turns to run it in; you should be able to see the rollers & cage move relative to the inner and outer race.
Version 2.0 - May 8, 2026: Initial public version.
Version 2.1 - May 18, 2026: Added Semi-enclosed Caps
608 Bearing V1 - The original version, with a different assembly design for the Races and Caps.
Filament Roller 608 Bearing - A variant with filaments as roller, inspired by the neat idea by @firstgizmo. It runs super light and it's similarly easy to assemble.
606 Mini Bearing - I was curious if the concept would go smaller and the answer is yes! This 606 bearing is only the size of a dime and runs just as well.
License:
Creative Commons — Attribution — Noncommercial
6
Redlow
