Parametrical Bearing for Air Soft BB

by StreetPiet Sep 30, 2016
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Came out a LOT smaller than I expected, and here I thought I knew BBs well enough.
ANother reason to spend the extra dosh for quality single-piece polished BBs as opposed to joined hemispheres huh?

With your permission I would like to use this bearing as centerpiece for a horizontal Filament Spool mount.

I agree! The quality of the BBs is equally important as the precision of the Printer. I had to test out the right settings for each of my printers. You can even try to carefully sand the Bearing down to a Fit.
...Otherwise it can be a bumpy ride ;-)

Please feel free to use this Thing for every possible Project that you can think of.
It would be a pleasure to see a new Make or a Remix of this Thing!

Hi, I've used this to make a bearing to sit my Filament rolls on,

What is the tol variable for, I've tried 0.35, 0.3 and 0.25 and only see the inner and outer diameters not giving the correct results, by 2x the tol value...

I'm using 6mm BB's and making a bearing to sit on a 19.2mm rod.

So with the following settings tol = .25 ID = 19.5, OD = 38, BBHeight = 8 ballDiameter = 6 wallThickness = 1
I get a bearing with an OD of 38.5mm and an ID of 20mm

So... can do set it to tol=0 to get the correct sizes?

What I was trying to do was get the balls to fit slightly more snugly, does the tol value change that at all?


i had some accuracy issues with my printer so i added the tol(erance) variable.
The bigger the value the more "room" for the bearing balls is generated.

i made some test prints with varying tol values until the bearing
ran smooth without to much wiggle room.

you can try values equal or bigger than 0

Hi, I really like the parametric approach to this, have printed one (still have to adjust the tolerance for my printer) and it works quite nicely!

I noticed that the rendering times are quite high and that F5 did not produce (at least not for me) any kind of 3D image.
I looked at the source code: there is code to show the BBs inside the bearing as greyed out (the for loop that starts with %). This for loop is inside the difference(){ ... } which it does not need to be (Scad tries to subtract everything from the BBs which does not work since they do not intersect).

If you move the %for ... outside of the difference() (i.e. above difference() and below 'BBstep = 360/BBs;') then it shows the 3D view with F5 and renders almost instantly. Hope this helps!

What size are these?
Are they comparable to any regular bearings?

Hi. The size is adjustable. Softgun Balls have a diameter of 6mm and Steel Bearing Balls for AirGuns have a diameter of 4.5mm - so for smaller bearings like a 608 you get into trouble because the balls are too big.

The Bearing is mostly usable for slow turning and no big axial or radial pressure, like in Thing http://www.thingiverse.com/thing:1799834

Printrbot simple Spool Holder Upgrade (Dirty Mix)