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Unread 03-16-2018, 07:07 AM
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Wobble in Vex short shaft ball shifter

We are using a Vex ball shifter short shaft in our own transmission design. We’ve noticed some wobble in the ball shifter gears. Still trying to pin down the cause of the wobble. One unverified theory os that there is some movement where the short 1/2” hex shaft joins the ball shifter housing.

Has anyone else noticed this issue?

Thanks in advance



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Unread 03-16-2018, 09:19 PM
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Re: Wobble in Vex short shaft ball shifter

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Originally Posted by MisterTim View Post
We are using a Vex ball shifter short shaft in our own transmission design. We’ve noticed some wobble in the ball shifter gears. Still trying to pin down the cause of the wobble. One unverified theory os that there is some movement where the short 1/2” hex shaft joins the ball shifter housing.

Has anyone else noticed this issue?

Thanks in advance



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The normal ball shifter is supported by a 0.75 ID bearing on the end of the shaft. After the larger ball gear, there is a c-clip and a wave washer, followed by the 0.75 bearing. In this arrangement the pinned hex shaft would have no influence on gear wobble.

Are you supporting the load catilivered further out with an R8 hex bearing? The hex shaft is retained by it's clearance with shifter end ID and a single roll-pin. I don't believe the hex shaft is a press-fit, so it certinaly could have some small side-play.
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Last edited by InFlight : 03-16-2018 at 09:28 PM.
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Unread 03-17-2018, 11:47 AM
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Re: Wobble in Vex short shaft ball shifter

Is it the shaft that is wobbling or the gear?

If it's the gear, check the broach/bore dimension. That can induce the wobble as well. If you find that is the problem, getting some metal spacers and shimming/springing out all the slack on the shaft can help mitigate the problem. But, ultimately, getting a more tightly fitting gear would be the fix.
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