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Steel ball bearing as Duo 250 trackball

Posted by: Bama on 2019-11-22 19:31:38 Hello All, I need a replacement 19mm trackball. I have a 19mm steel ball bearing.  Is this safe to use the metal ball bearing as a replacement?  My reason for asking is that I can see what looks like copper at the base of the trackball assembly.  I attached a picture. Thanks, Bama

Posted by: Papichulo on 2019-11-23 07:29:51 I think plastic is better

Posted by: maceffects on 2019-11-23 09:39:33 It will work just fine though the feel of the movement will be different.

Posted by: Trash80toHP_Mini on 2019-11-23 10:00:25 Fabulous idea, I hope it works out. Is 19mm the trackball spec or did you use a caliper on the original? I don't have a Duo open ATM so I couldn't check. I don't think the ball would touch the brass, check if the rollerball is supported by the mechanism's rollers? If the copper/brass ring is the bottoming out support it's a no go. If so the weight of the ball bearing may stress the support structure? Dunno, I've got one colored ball so I haven't looked for them, but if marbles are available in 19mm they'd make some crazy trackballs. Smoothness might be a concern in terms of frictional interface differential with the roller material? On a side note, the mass of a bearing would have made tweaking Bezier control points a lot more accurate given the inertial upgrade when I was doing that in the field.

Posted by: maceffects on 2019-11-23 10:02:26 I have a couple chrome and gold platted ones that look amazing in the Duo and 1x0 series.  I always liked the colored plastic balls that were once popular.

Posted by: Solvalou on 2019-11-23 10:09:00 Failing that, there's a fairly reasonably priced complete NOS trackball assembly. https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F142744323329

Posted by: Trash80toHP_Mini on 2019-11-23 10:12:32 Just checked marbles out, a 3/4 inch "Shooter" is 19.05mm!  [😀] edit: Just checked the PB100 trackball is about .9885" and Outside the North America, 1-inch marbles are sometimes used as shooters. One wonders what  was used in trackball protyping? 100 series Powerbooks are an oddball size at 1 3/16 in. so they're 3/16" short of the 1 3/8" marble standard.

Posted by: Bama on 2019-12-02 05:33:09 19mm steel ball bearing works terrific!   Now I only need a retaining ring. (I don’t want a loose ball bearing bouncing against my glass screen when the lid is closed.) Any ideas for this part in the United States?

Posted by: Trash80toHP_Mini on 2019-12-02 08:38:41 Very nice, where'd you get the ball bearing? Gotta get a few marbles as well to test the mass differentials for feel.

Posted by: Bama on 2019-12-03 14:26:57 Ebay...19mm steel ball bearing... China of course.  🙂

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