Tel: 860-571-3602  |
Tel: 860-571-3602  |

FAQ – Precision Balls

Q: What gives chrome balls better performance properties than plain carbon steel?

A: Chrome balls contain greater percentages of key alloying metals, including chromium, silicon and manganese. Chromium contributes toughness, and helps resist wear, corrosion and discoloration; silicon and manganese both increase strength.


Q: Where are precision miniature balls used?

A: Precision miniature balls are those under 1/8 inch (3 mm) in diameter. Precision miniature balls are commonly used in medical, dental and optical instruments, miniature bearings, ball screws and pumps. Material options include chrome steel, stainless steel, tungsten carbide, plastic and glass.


Q: What are the best options for stainless steel bearing balls?
A: Our page on stainless steel bearing balls can help you decide.

Q: What are some good criteria for deciding whether a ball or roller is best for a given rolling motion application?
A: There are 6 main factors to consider – here’s how balls and rollers compare on that basis:

Q: What are the main differences between 300 and 400 series stainless steel balls?
A: 300 series “austenitic” stainless steel balls contain chromium and nickel and are non-magnetic. They have better corrosion resistance than 400 series, (in fact, the highest corrosion resistance of the stainless group). They are less brittle, and can be hardened by cold working. A 400 series stainless steel ball is “straight chromium.” It contains more carbon to make it magnetic, and offers less corrosion protection than 300 series. “Martensitic” can be readily heat treated to increase hardness, making it more brittle. Martensitic grades are specified for applications that demand strength, hardness and wear resistance.

Q: What standards does Hartford adhere to for ball manufacturing?
A: Hartford products conform to these major standard industrial specifications for precision balls:

  • ANSI / AFBMA Standard 10 Metal Balls
  • ISO 3290 Rolling Bearings – Balls – Dimensions and Tolerances
  • DIN 5401 Finished Steel Balls for Rolling Bearings
  • ASTM F 2215
  • ASTM F2215
  • ASTM F2215-08
  • ASTM F 2215-08
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