Posted by John Swensen on March 13, 2002 at 12:47:50:
In Reply to: Re: Re: Re: Re: Dent eraser posted by Kristian on March 12, 2002 at 16:38:34:
For bearing balls, your choices are carbon steel (cheapest, hard "skin", tough core), chrome steel (hard throughout the ball), and 440C stainless (most expensive, not as hard as chrome steel, intended for corrosive environments).
At least with the MSC catalog, chrome steel offers the most size choices (up to 2" diameter for about $16, which we tubists would want), and is probably what you would get if you just asked a bearing supply place for a large-diameter ball. Chrome steel is moderately "magnetic" (has a moderately high magnetic permeability), but is not nearly as "magnetic" as materials specifically engineered for magnetic permeability. However, most of these alloys are not very good for bearings, and having them specially made for dent balls would be prohibitively expensive.
I would be astonished if the Dent Eraser came with other than chrome steel balls.