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New product: Pololu Ball Caster with 1″ Plastic Ball
This new ball caster is an improved version of our original ball caster with 1″ plastic ball, with better rollers for reduced friction and a two-part ABS housing that securely encloses the plastic ball. The ball can rotate freely in any direction, making this caster suitable for use as a third contact point for wheeled, differential-drive robots weighing up to around ten pounds (the smaller ball caster on our 3pi robot is an example of this kind of application).
We designed the rollers to be replaceable by ball bearings for even better performance, and we expect to release a version that includes them by the end of summer. If you’re impatient, you can make this upgrade yourself by getting some standard 3×7×3mm ball bearings (3 mm inner diameter, 7 mm outer diameter, 3 mm width) along with 3 mm diameter dowel pins to hold them. The left picture below shows dowel pins we crudely cut ourselves in 8 mm segments from a longer rod.
You can also replace the included plastic ball with a metal one (not included) if a harder ball would better suit your application, but please note that a metal ball is much heavier and will not necessarily increase the load-bearing capacity of the ball caster.
Check out the product page for more information, or visit the ball caster category for more options, including ball sizes down to 3/8″.