Cat XLS pivot balls U7150

[slazzaro]

Hello! Does anyone know, or can anyone with a Cat XLS re-re take a measurement of these ball studs?
Are the balls 5.8mm diameter?
Thanks in advance! Cheers!

[XLR8]

Hello! Does anyone know, or can anyone with a Cat XLS re-re take a measurement of these ball studs?
Are the balls 5.8mm diameter?
Thanks in advance! Cheers!

5.5mm

[slazzaro]

Thank you! So they're not good for me.. I'll look further for some "vintage looking" 5.8 ball studs to fit my Yokomo 870c. The original ones are so rare!

[juicedcoupe]

Are you looking for the ball studs or the links?

I believe that the RPM links for Traxxas vehicles will fit 5.8mm balls. They are made in two lengths and multiple colors.

[Coelacanth]

5.8mm ball studs and open ball-ends are pretty common in vintage Kyosho kits, mainly the Optima series...used for tie rods and camber links, if I'm not mistaken. I believe they're 3mm threaded studs.

[XLR8]

Yes, vintage and re-re Kyosho also uses 5.8mm ball connectors and they are 3mm thread.
Also, off-road vehicles from MST uses this size as well. Here are some part numbers to add to your search:

Not sure if any of this is helpful.

EDIT: A Main has the 210491's

[slazzaro]

Thank you all! I'm after ball studs. Ideally with inner thread and hex, but I think I'll have to settle for any alternative solution from Kyosho or other makes. After all the ones with external thread do the same job and look similar enough once installed.

[juicedcoupe]

https://www.amainhobbies.com/kyosho-5.8mm-flanged-hard-ball-3mm-thread-4-kyow0158/p-qqqqqzyqlc2xactz

Just search for "5.8mm pivot balls". You will find some options, not all will be threaded.

[XLR8]

As juicedcoupe suggested, I searched Amain's website for "5.8 ball" and found two pages of ball connectors and related products in this size. Besides Kyosho and MST, there are 12 different manufacturers listed that make a 5.8mm ball connector. This can't be mere coincidence, there must be a reason. Why 5.8 I wonder.

[slazzaro]

I know! I was also wondering why 5.8?

[XLR8]

I know! I was also wondering why 5.8?

After giving this more thought, I'm guessing 5.8 is the largest ball diameter that can consistently be turned from 6mm diameter bar stock.
What's interesting is that smaller diameters will result in less friction so Schumacher makes 5.5mm and RC10 ball studs are even smaller (although AE uses #4 screw threads which are also slightly smaller than M3).
With M3 as the basis, ball connectors made from 6mm bar yields the greatest range of motion at lowest material cost. Just speculating of course.

[jwscab]

Yeah that's why. The 6mm hex is used to turn into a ball.

Same with the associated ball. Starts with 3/16" hex stock.

[slazzaro]

That makes a lot of sense, thank you both!