Quote:
Originally Posted by utopia
Hmmm ... I'm not so sure about that.
Surely the 6mm balls do not track at a single point but rather they make contact across the full width of the races which have a matching 6mm concave form.
The larger 1/4 inch balls will probably make contact at the two extreme edges of the concave form of the races.
This may mean that they avoid the central, indented area to some extent and initially run more smoothly but the loading will be concentrated over two narrow bands instead of across the full width of the races and they will probably deteriorate in short order.
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I don’t see how the 6mm balls can bear on the full width of the ball race as it would stop the balls from rolling?
The purpose of the balls is to take away friction by allowing the balls to roll, but the linear (Or circular in this application) distance travelled per revolution of the ball is proportional to the perpendicular distance from the axis of rotation of the ball. Taken to extreme, and ignoring the friction between top and bottom races where they meet, if half of the ball were within each ball race, rotation of the balls would create movement at the top and bottom of theball, but progressively less movement as you approach the axis of the ball. The difference in movement would require the balls to slide across parts of the ball race, or lock the bearing solid if it can’t slide.
Tapered roller bearings are better because they can bear across full width of the roller without needing to slide, provided the geometry of the tapers is accurate.