Printed 608 BB bearing by TheRooster
Printed 608 bearing using BB's by TheRooster
Some days, such as today, I love being wrong. 
The other day I suggested printing a 608 bearing using 4.5mm BB’s would be impractical given the dimensions of a standard bearing. There were a number of very well thought out responses from Tre3 and TheRooster to my wild12 accusations.3
Among other excellent points, Tre3 pointed out that with careful purchasing you can find ball bearings as low as $0.05 per bearing. 4 That’s pretty dang low. TheRooster said he was able to pick up 2500 zinc plated steel BB’s for $4 from his local big-box store. That’s about $1.70 for all 53 bearings required for a RepRap. Cheap BB’s are all well and good – but you’d still need to find a way to shoe-horn them into a printed 608 sized shell.
And that’s exactly what TheRooster did – he designed, printed, and assembled a 608 sized bearing utilizing those 4.5mm BB’s as the ball bearings. I cannot wait to try this design out. I realize the labor costs involved in creating your own ball bearings is probably prohibitive.
I think this misses the central questions:
- Just how far can you push a 3D printer?
- When you can make nearly any arbitrary shape out of plastic, just what are the limits?
- What is possible once your biggest cost is the time required to assemble the parts in front of you?
Tre3: I was going to take you up on your offer to test my plastic bead bearings, but they are officially garbage now that I’ve seen TheRooster’s improvement. However, I would love to see how TheRooster’s printed ball bearings using BB’s match up to your tests. Are you guys up for the challenge?
- Drunken? Intoxicated? [↩]
- BUI – blogging under the influence! [↩]
- If I were really smart, I would claim that this was a bit of slight-of-hand reverse-psychology on my part. Alas, I am just not so clever. Or devious.
[↩] - Given that each bearing requires roughly 15-20 balls and there are 53 bearings in a RepRap, this comes to $39.75 for the lot. [↩]
| Tagged with | ball bearing, bb, bb bearing, bb's, bearing, printed ball bearing, printed bearing | 5 comments |
5 Comments so far
BobEast
So, Is there a fancy assembly trick required? Or can you just print half pause the print, add bearings then continue? It appears to be all one print in the photo.
GregT
For a fully homebuilt solution, I’d think it would be possible to create BBs instead of buying them. For instance, I see little BB-sized balls of solder fall off my soldering iron all the time.
tre3
Lets do this! There may be a bit of a delay as I’m flying overseas to kick off a manufacturing of a product… I return home and to my testing fixtures before Thanksgiving (but probably won’t be able to test until early December). That leaves plenty of time to iterate/tune and duplicate a few copies
I can also test the plastic version too if you’d like – something to compare to…
email my spam address (I’ll check it): notfrequentlychecked {at} g m a i l [dot] com
For note 4 – the $0.05 isn’t for just the balls – it’s for an entire 624ZZ roller bearing
On lighter note… I prefer to carry my 3D printer rather than push it
Also, my limitation for 1 pass is a 140mm cube :p
TheRooster
Each bearing only takes 9 balls. Not 15-20. Also, most of the bearings for a RepRap are 624 right? I’m not sure that size would be printable.
I have printed 4 or 5 of these. Depending on how much ooze your printer has, the cleanup is the most labor intensive part. If you have zero ooze, you should have zero cleanup and could make these in bunches. The printing will be slower than the assembly.
Quick story. I assembled one bearing and must have missed some ooze somewhere because the action was very rough. So I tried to remove the BBs one at a time in the reverse order of assembly. I ended up delaminating the center piece. Oops!
As for printing and assembly, You could nest the two parts, but I found that just makes more problems with the strings and ooze. I print each part separately. Don’t worry about installing the BBs after printing, they go in easily. That’s the nice thing about working with plastic instead of metal. The first six BBs go in easily, just twist the center piece slightly (hard to explain but easy to do.) The last three just get shoved into the larger gap with pliers. The plastic distorts slightly and the BBs snap into place.
I also spent some time this weekend working on a design for a linear bearing. I have a good start with a nice 16 BB “racetrack”, but ran into tolerance issues when trying to combine three of these into a linear bearing. I have an idea that I’d like to try when time permits.
TheRooster
Alright tre3, I’ve made a cheap linear bearing from BBs and Makerbot ABS. I tried many more complicated versions, but this is by far the best. Only two parts, both identical. Requires a couple bolts, but you’d need those to attach the bearing to your part anyway.
I ran the bearing without grease and it worked pretty well. A little bit rough, but not too bad. I think with grease it will smooth right up. I think the bumps come when a new ball makes contact with the bar. Maybe adjusting the tension on the bolts would minimize that too.
Anyhow, go here to take a look and/or download.
http://www.thingiverse.com/thing:4718