I have a new mini with which I want to experiment with different ball sizes. I'm not sure which ball bearing material I need to use. Stainless steel is generally not highly attracted to magnets, but this is what most of the ball bearing variety kits are made of. What material (or stainless steel grade) are the balls that come with the Sisyphus made of, and what other materials/grades will also work?
@stevetheevans - Pretty much any ferromagnetic object you place over the magnet will get pulled through the sand. Spheres are much nicer (IMO) because they roll (as opposed to skidding). As far as material, all non-stainless alloys ("carbon steels") will work, and you really don't need bearings that are high precision (closer to a perfect sphere) or hardened. And you're partially correct about stainless - many alloys are very weakly attracted to a magnet (300-series) - but 400-series are ferromagnetic and work fine. Home Depot carries a small variety of single ball bearings in their specialty fastener section.
I can save you from a (small, inexpensive) mistake. Don't buy these: https://www.amazon.com/gp/product/B07Q6LFYQ5/
I wonder if there's something in the world that's like a ball bearing with a textured surface? That might produce some cool effects for things that are coarse linework, though I'd guess they'd make a total mess of fine details. If not it might be easy to 3d print a thin cover for one.
@patti Well, I had just ordered these on amazon because it was so frustrating trying to find 400 grade ball bears, I thought, "What the heck for $10?" I canceled the order but it might be too late. Where the heck is a good place to get an assortment of balls that will work? I want to try smaller ones than are offered on the sisyphus-industries.com site. Home Depot doesn't say what grade the balls are. And all the industrial B2B sites deal in quantity.
@stevetheevans - not 100% sure that Home Depot's single bearings are not stainless, but I doubt they'd carry stainless (it's more expensive and less hard than carbon steels). But you can be absolutely sure if you just bring a small magnet with you next time you're shopping. BTW - you do not need 400-series stainless. Regular shiny (polished) steel balls stay that way over long periods of time when running on Sisyphus. I assume the sand does the "cleaning."
the majority of industrial ball bearings are going to be 52100 steel (very hi carbon, relatively hi chromium and some manganese and phosphorus) these are pretty easily atrracted to a magnet. many are also chrome plated so they will be shineyer and last longer
I found that going down to my local Ace Hardware and picking through the specialty trays yielded a nice selection in sizes for a reasonable price. Very easy and convenient.
We take your privacy seriously and will only use your personal information to provide you with the products and services you request from us. Please see our privacy policy for more details.