Hi! I figured this may be the best place to ask but do direct me elsewhere if I’m mistaken.
Has anyone compared a dual rail linear ball bearing setup like shown here in insight 285 on the sample images, to something more simplistic but potentially having some axial wiggle (and resultingly, friction) using a setup like is shown for the ball bearing carriage here in sample images? I’m specifically trying to determine the option that has the least amount of off-axis motion and friction. I’m looking to make a thrust controller for a hall effect joystick setup, so smoothness is important.
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I’m no expert but I have had a little relevant experience. I reckon off axis motion and friction are two not necessarily related parameters. Looking at the example images I believe the example using the linear bearings on two round shafts would certainly have less off axis motion. But it probably has a little more friction in the direction of travel. The carriage with the ordinary ball bearings does not appear to have any control of off axis motion in the axis at right angles to the direction of travel but might have slightly less friction. My point is that the more closely controlled the off axis motion is, the more friction there may be. However, there is probably not much in it.
If I wanted to build a carriage that only moved in one axis I would go for the design with the linear bearings on the 2 round shafts. I think you will find the linear ball bearings do not introduce significant friction. That is really the point of any form of ball bearing.
Ian
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Hi Lewis,
I agree with Ian - many great points there.
Axial wiggle, will be down to the tolerance on each of the parts (pretty good for goBILDA parts compared to other suppliers).
A linear rail bearing by itself might be a good way to go? Steel Viper-Slide (10-Ball Carriage, 240mm Length, 174mm Travel) | Buy in Australia | GB-2500-0010-0240 | Core Electronics (similar to this)
By smoothness, do you mean the amount of force required to move the lever is constant along the length or interns of backlash, from bearings?
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I had initially considered a linear rail on account of it being a neat package, but I’m looking to add a center detent to indicate the center of the axis, using something like a spring/ball plunger and I’m not sure how neatly that would work on a linear rail.
I had meant smoothness in terms of bearing backlash and axial wiggle, combining in the perception of the user having a controlled sense of motion over a single direction, for example without a noticeable jerking into place or rattle when applying a sudden force not perfectly along the axis.
Ian’s right here, by the nature of the mechanism it does seem the linear bearing route would be the better one.
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