MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.

Download Now


Recirculating Ball Slide for 1" Square Tube (Improved)

by LoboCNC Aug 20, 2017
Download All Files

Thing Apps Enabled

Please Login to Comment

I've got one printed out and running really rough. I may need a finer print or more care to smooth the channels, but I suspect it is really low-grade BBs that aren't very round. Grabbing a random BB I can measure it varying at least 4 thousandths in diameter.

Do you have a specific airsoft BB you like to use for these types of projects? Once I get some decent BBs in there I can play with troubleshooting the action I'm seeing.

The BB's I used (marketed as Smith & Wesson) are all quite accurate - within 0.001". I suspect any name brand BB's will be pretty accurate as they'd probably cause jams in airsoft guns if they weren't.

I swapped out the BBs and the improvement was dramatic.

I originally used Colt 0.12g BBs I could find in my local big-box store. I am now using EliteForce 0.25g BBs and the movement is MUCH smoother. I can easily adjust the screws to provide free movement without any binding like the old BBs caused.

I'm printing more of these at a finer resolution, for hopefully even smoother movement. I'll post pictures of my make once I have it incorporated into a functioning mechanism.

Let me put a bit of criticism. Looks like I do not understand something... IMHO the loop of slider's balls will never re-circulate. Because if both rows of the loop are contacting the metal surface at same time, they got force in controversial direction, that will prevent the balls from changing their positions in the loop. I'm in doubt that the balls even will roll staying on same place - because next ball in row will prevent the rotation when moved to the U turn of the loop. So technically there is no difference between having these rolls, or just having small pins printed. Low friction pair (plastic/aluminum?) will just create illusion that it works.
If it high loaded node of the machine, it should get a wear signs very soon.

Perhaps my explanation in the Description is not quite clear. In the oval ball track, one straight section side of the oval is recessed so that the balls on that side are not pressed against the rail, allowing them to recirculate freely. The round ends of the track are also recessed. The recess is kind if hard to see bacause it is only about 1/2 mm.

Is the best way to print this with no supports to print as is given in the stl file? or should I reorient it with one of the sides flat?

Print as oriented in the STL file. You may need to add a raft or brim if you have bed adhesion issues, but no supports are needed.

Sweet, thanks for replying so quick!

"delta ?" as in: Could this be used for a delta-style printer? Sure, I don't see why not.

Nice work! Ever tried BB gun BB's? If not would you be able to please provide a modified design for BB's? I think they're 4.5mm diameter.

I use 6mm ( or 0.6 cm) BBs , no problem.

I suspect 4.5mm steel BB's wouldn't work well. I'd be afraid that the harder material and smaller diameter would just dig into the 3D printed plastic. Redesigning for smaller balls would be a bit of work as you usually end having to fiddling with clearances. I'd be happy to post the Solidworks CAD file, though, if you'd like to modify it yourself.


Excellent work. We plan on using this on our FRC robot this year.

We would greatly appreciate it if you could plase post the Solidworks CAD files for us so we can add this to our assemblies for our robot model.

Thank you.

Hello, compared to existing bearing systems that so presiso and smooth results this?

I've added some comments to the Thing Details talking more about precision and smoothness.