Steel ball bearing as Duo 250 trackball

[Bama]

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

 

[Papichulo]

I think plastic is better

 

[maceffects]

It will work just fine though the feel of the movement will be different. 

 

[Trash80toHP_Mini]

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.

 

[maceffects]

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. 

 

[Solvalou]

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

 

[Trash80toHP_Mini]

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.

 

[Bama]

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?

 

[Trash80toHP_Mini]

Very nice, where'd you get the ball bearing? Gotta get a few marbles as well to test the mass differentials for feel.

 

[Bama]

Ebay...19mm steel ball bearing... China of course.