This cool little ball forming jig design has only been around for 5+ years. It's a clever design - it replaces the cross slide on a standard Mini Lathe which is only 2 bolts, and take just a couple of minutes. I is very easy to set up for convex ball/hemisphere forming, and also convex shaping.
https://youtu.be/FxQqDfha-CA
I like the "inexpensive" part. :D But can you provide information on the source? I've seen many of those shop made, but not one to purchase inexpensively.
It looks like this one. https://www.amazon.com/dp/B096Y1ZY3N...f_=as_li_ss_tl (Amazon link)
Edited to include the affiliate link from the description of the original video.
I put a link in the description of my video to one that you can purchase inexpensively.
Thanks. it looks similar, but his appears better "finished".(?) I see there is quite the range of those on Amazon, but didn't find one that was a solid match. Better/Worse? Who knows. Too small for my lathe, but I mostly need smaller "balls" and related, so if cheap enough, it could be adapted to fit.
Yes, this is what I bought
I watched it on this site and didn't see the youtube comments. Thanks. Looks like you lucked out with one that appears to have a better finish that that shown on Amazon. Thanks for the video and information. I've been "planning" to make one for years, but have more "real" projects than I can keep up with, so tool projects often get pushed back. Then when I need a surface and don't have the arc cutter, I wind up with form tools and/or files. A simple cheap adaptation could be the solution for something like 95% of what I need to make. In fact, a very small one would have been near perfect for a 1/4" ball race I had to make with some very temperamental precipitation hardening stainless that work hardened with even the briefest pause using HSS form tools. For something that small, yours would even be too big, but might make a suitable base for a slide for mounting a small enough bit. Maybe a Top Notch or something? Hmm.