Precision Ground Balls

All Seals produces precision ground rubber balls to exacting tolerances and stringent rubber compound specifications.  After the balls are molded, they are finished by a high-speed, accurate grinding process.  The finishing process eliminates the mold parting line and results in a smooth and uniform surface.  Additionally, the machining process used on our precision ground balls provides the consistent, close diametrical and spherical dimensions that are required to produce an effective seal. We stocks many sizes of Nitrile Ground Balls in prepackaged quantities. Please call for a quote on custom size balls and compounds.

Sizes (Diameter) Tolerances
Inch Decimal Inch Millimeters Diametrical (In.) Spherical (In.)
3/32 .093 2.36 .003 .003
1/8 .125 3.18 .003 .003
9/64 .140 3.56 .003 .003
5/32 .156 3.96 .003 .003
3/16 .187 4.75 .003 .003
7/32 .218 5.54 .003 .003
1/4 .250 6.35 .003 .003
5/16 .312 7.94 .003 .003
3/8 .375 9.53 .003 .003
7/16 .437 11.11 .004 .005
1/2 .500 12.70 .004 .005
9/16 .562 14.79 .004 .005
Sizes (Diameter) Tolerances
Inch Decimal Inch Millimeters Diametrical (In.) Spherical (In.)
5/8 .625 15.88 .004 .005
3/4 .750 19.05 .004 .005
1 1.000 25.40 .004 .005
1 1/8 1.125 28.58 .006 .008
1 1/4 1.250 31.75 .008 .008
1 3/8 1.375 34.93 .008 .008
1 1/2 1.500 38.10 .008 .008
1 5/8 1.625 41.28 .010 .010
2 2.000 50.80 .010 .010

Commercial Grade Balls

All Seals's commercial grade balls are manufactured for a variety of industrial applications.  They are produced to RMA Class 3 commercial tolerances in a wide range of specifications and compounds.

Compounds for Commercial Grade Balls
• Pure Gum Natural Rubber
• Nitrile (Buna-N)
• Viton® †
• Neoprene
• SBR
• Silicone
• Urethane
†DuPont Dow Registered Trademark

Diameter of Standard Commercial Grade Balls
Inches Inches (decimal)
5/8 0.625
7/8 0.875
1 1.000
1 1/8 1.125
1 1/4 1.250
1 3/8 1.375
1 5/8 1.625
2 2.000
3 3.000

RMA Class A3 Tolerance
Size (in.) Fixed +/– Closed +/–

0.00 - 0.40

.008 .013
0.40 - 0.63 .010 .016
0.63 - 1.00 .013
 .020
1.00 - 1.60 .016 .025
1.60 - 2.50 .020 .032
2.50 - 4.00 .025 .040
4.00 - 6.30 .032 .050

Sponge Rubber Balls

All Seals's chemically blown sponge balls are molded from a premium grade natural rubber compound. Our molding process ensures uniform cell structure, excellent physical properties, good colorability, and smooth skinned surfaces.

Available Colors:*
Red, Blue, White, Green, Yellow
* Exact color shades cannot be guaranteed.

Properties

Material:

Natural Rubber

Hardness: 70 +/– 5 (Shore00)
Tolerance: +/– .040 in.
Density: 25.0 lb/cu.ft.
Rebound: 40%
Tensile Strength: 140 psi
Elongation: 480%
Sizes (diameter)

Nominal (in.)

Actual (mm)

1 1/8 28
1 3/8 35
2 50
2 1/4 56
2 1/2 63
2 3/4 70

Other sizes and compounds are available as specialty orders. Contact your Customer Service Representative for more information.