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An industry standard for more than 70 years, Thomson proudly serves precision industries with specialty and production runs of standard and non-standard balls. At our A2LA accredited calibration laboratory, our precision balls are made with pride and ideal for bearings, ball screws and many more applications.
Made with pride, backed by accreditations:
Manufacturing Capabilities
Holding ourselves to the higher standard:
NEWS:- You Should Know-
440C DFARS Readily Available- 1/16”, 3/32”, 1/8”, 5/32”, 3/16”, 1/4”, 5/16”, 11/32”, 3/8”
Meets DFARS 7009/7014, AMS 5880, AMS 5630, QQ-S-763, ASTM A276, AMS 2759, ASTM F2215, HRC 58-62, AMS 2700, NADCAP Heat Treat
NADCAP Passivation, Retained Austenite Available
Pioneer Steel Ball was founded in 1946 in Unionville, Connecticut by five men who had extensive experience in the steel ball industry. The idea to form the company took root several years earlier, but since the founders did not want to jeopardize the war effort in any way, they waited until the war had ended. In the forties and fifties, Pioneer, produced carbon steel balls for bearings and the automotive industry. In addition, the company manufactured a variety of steel sizes and shapes for the burnishing industry. Pioneer’s growth outpaced their capital and in the early ‘50s they sold the company to Pittsburg Steel with the option to repurchase it at a later date. Unfortunately, they bought back the company a few months before the devastating hurricane and flood of 1955. Located on the banks of the Farmington River, the company took a direct hit and was destroyed. However, it was rebuilt by two of the former five partners who later expanded the product lines to include High Carbon Chrome SAE 52100 as well as a full line of stainless steel types: 440C, 302, 316. The partners also added lapping machines to produce tighter tolerances and improved surface finish. One of their greatest accomplishments was to develop the 36” flashing machine, the largest at that time. This accomplishment was the result of their combined expertise which had been acquired over sixty years in the steel ball business. Pioneer’s innovative leadership continued with the development of extremely strong hollow stainless steel 440 balls for the air cargo industry. They also developed a special stainless steel type 431 gold- plated with extremely high tolerance for the automobile air bag deployment mechanism.
A second company in the industry, ABEK, had been founded in 1976 by two people with 20 years of miniature ball- making experience. Unlike Pioneer, which specialized in small to large balls, ABEK specialized in miniature balls that were 1/16 of an inch in diameter or smaller. With its expertise in this area, ABEK was able to manufacture high precision balls as small as .012 inches and became a leader in this field.
It was this expertise, combined with Thomson Industries determination to have a USA supplier of high quality, that had led it to purchase ABEK in 1982. Once the purchase was finalized, approximately 14% of ABEK’s sales were to Thomson divisions. At that time, ABEK manufactured the miniature and small balls sizes, and purchased the larger sizes from Pioneer, which it then sold to Thomson. ABEK, was combined with Pioneer in 1988 to form Thomson Precision Ball. This enabled Thomson Industries to satisfy all of its’ ball requirements. Approximately 14% of Thomson Precision Ball capacity is still dedicated to Thomson Industries.
Precision Balls | 2619 KB |
High Chrome Carbon steel, typically known as Chrome Steel, is a workhorse of the precision motion industry. It is the most common material in radial bearings, linear bearings, and ball screws. All Thomson’s standard products meet AMS-6440 at a minimum and are through-hardened to HRC 60-67 to achieve a fine surface finish and high load capacity. Single lot hardness typically is within two (2) points. Our Chrome 52100 balls ship with a preservative light oil. If you require dry product, please contact Customer Service.
Type 440C Stainless Steel has similar physical properties to Chrome Steel with a higher corrosion resistance to many common fluids. It is commonly used in specialty radial bearings, linear bearings, and ball screws as well as check-valves and plug balls. All Thomson’s standard products meet AMS-5630 at a minimum and are through-hardened to HRC 58-65 to achieve a fine surface finish and high load capacity. Single lot hardness typically is within two (2) points. All Stainless steel from Thomson is passivated.
Type 430 Stainless steel is an unheated treated, economical stainless material that provides corrosion resistance at low cost. Typical applications for this product include cosmetic mixing media, decorative trim, and light duty ball valves. For SS430, Grade 1000 is standard. All Stainless steel from Thomson is passivated.
Type 302 Stainless Steel is widely used in the food industry for its good corrosion resistance and economical costs. It is commonly known as 18-8 stainless. Its non-annealed hardness, created by cold working, is typically Rockwell “C” 25 to 39. Type 302 can be annealed to remove any cold worked magnetism and will result in a hardness of Rockwell “B” 75 to 90. For Type 302, Grade 100 is standard. All Stainless steel from Thomson is passivated.
Type 316 Stainless Steel is a more corrosion resistant version of the 300 series than 302, mainly due to the higher levels of Molybdenum and Nickel. Its non-annealed hardness, created by cold working, is typically Rockwell “C” 25 to 39. Type 302 can be annealed to remove any cold worked magnetism and will result in a hardness of Rockwell “B” 75 to 90. For Type 316, Grade 100 is standard. All Stainless steel from Thomson is passivated.
Type 440A Stainless Steel has similar physical properties to 440C with a lower carbon level for workability. Thomson uses 440A for our Aerospace hollow balls. Our 440A hollow balls meet AMS-5630 and are heat treated for strength and through-hardened to HRC 52-60.
Brass balls provide excellent resistance to corrosion in water, is nonmagnetic, is an excellent electrical conductor, and is very machine-able. Its typical hardness is Rockwell “B” 75 to 87.
Silicon Nitride Balls are a popular choice among bearing designs and other high precision product applications. When compared to steel, this material offers a 60% reduction in weight, up to twice the material hardness, a coefficient of thermal expansion that is 70% less than steel, and a temperature operating range up to 1800° F (982° C). Silicon nitride balls are non-corrosive, anti-magnetic, and excel in low noise, high rigidity, and high load carrying applications. Thomson’s products are made to exceed ASTM F2094 Class II.
Industrial Atmosphere | Hydraulic Oils (Petroleum) | Fresh Water | Salt Water | Food Products | Fruit and Veggie Juices | Milk | Alcohol | Hydrochloric Acid 40% | Sulfuric Acid 40% | Phosphoric 40% | Nitric Acid 40% | Citric Acid | Ammonia Liquids | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
52100 Chrome | C | A | D | D | - | - | - | C | - | - | - | - | C | B |
440C Stainless | B | A | C | C | B | - | A | A | D | D | A | A | A | A |
302 Stainless | B | A | B | B | A | - | A | - | - | - | A | - | - | - |
316 Stainless | B | A | A | A | A | A | A | A | D | D | A | A | A | A |
Brass | C | B | C | C | D | - | C | C | - | D | D | - | D | - |
Monel | C | A | A | B | D | C | C | A | D | - | C | - | - | A |
Nylon | A | A | A | A | - | A | A | A | D | D | D | D | C | - |
Viton | A | A | A | A | A | A | A | A | A | A | A | A | A | D |
Ceramic | A | A | A | A | A | A | A | A | C | D | C | A | A | A |
Titanium | - | - | - | - | - | - | - | A | C | C | - | A | A | - |
Letters indicating order of preference: A = Excellent, B = Good, C = Fair, D = Poor
Standard Ball Diameter is the value that is used for the purpose of general identification of a ball size (1/4”, 6mm, etc). Check out our “Quality Assurance” section to learn about measuring a ball.
Specific Diameter is the amount by which the lot mean diameter differs from the nominal diameter, accurate to the container marking increment for that grade. The specific diameter should be marked on the unit container
Thomson Precision Ball offers a full range of sizes from 0.011 inch to over 2.0 inches in diameter, in US standard and metric sizes. Our specialty is product as small as 1mm and up to 1/2 inch in diameter.
The ball grade is a specific combination of dimensional form and surface roughness tolerance. A ball grade is designated by a grade number. Thomson Precision Ball makes all of our standard products to exceed standard set by ISO 3290.
The specification defines the upper limits of the tolerances. The smaller the Grade number, the more precise the ball is. The chart below is a guidelines based on ISO 3290 and Thomson’s specifications. See our “Quality Assurance” section for additional details.
The Ball Gauge is the prescribed small amount by which the lot mean diameter should differ from nominal diameter, this amount being one of an established series of amounts. A ball gauge, in combination with the ball grade and nominal ball diameter, should be considered as the most exact ball size specification to be used by a customer for ordering purposes.
M05 = Nominal -.0005” (1/2” - .0005”)
P05 = Nominal +.0005”
P15 = Nominal +.0010”
As always, if you’re unable to locate the actual diameter, material, grade, or specification here our website, Customer Service would be happy to check our full inventory for you or create a quote for custom material. Since we manufacturer in the USA, we can have your custom product shipped typically in 4 weeks but as little as a week.
This part number is not available for sale online but may still be available for sale. Click here to contact Thomson Customer Support.
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