The Specifications for the ASTM Bearing Shaft Quality Bar

 

The drive shaft in this motorcycle is sturdy and flexible.

The American Society for Testing Materials publishes quality standards for bearing shafts. Bearings rotate, or turn, around a straight bar or rod, which transmits energy, motion and torque. The rod, or shaft, may contain gears or wheels and end in the propeller of a ship or the drive shaft of an automobile. Specifications for quality bars are precise size, finish and ease of fit within a bearing or within the housing and the load direction of load within.

Automotive

1. Automotive thrust bearings and contained shafts are mounted assembled. Quality steel automotive thrust bearing shafts carry heavier loads than polymer bearings, but polymer shafts are chemical resistant and do not corrode or rust. Automotive or truck camshafts are up to 76 inches long in 5/8 inch, 3/4 inch, 7/8 inch, 1 inch, 1 1/8 inch, 1 1/2 inch and 2 inches tapered diameters. Polishing the camshaft removes wear and tear due to high speed and pressure. Thrust chrome and steel axial bearing shafts carry the heavy load at the end of the car's axles.

In 2011, energy efficient automotive shafts range from single bearing and seal to powertrain shafts, which reduce CO2 emissions. The low-friction powershafts reduce emissions and increase fuel economy. The driveshafts reduce CO2 emissions. Light alloys are used for suspension and sealed mechanical assemblies contain hub bearing units.

Aeronautic

2. Jet engines operate at speeds and temperatures which stress maximum performance of mechanical components. Jet engines are scanned with an electron microscope for bearing flakes or fragments because bearing performance in jet engines is crucial to the safety of passengers. Jet engine roller thrust bearings are subjected to high-speed rotating shafts.

Roller thrust bearings respond to internal engine speed and pressure to leverage gyroscopic 15,000-pound loads on the aircraft. If the highly-loaded bearing is chipped or flaked, the bearings must be oiled. Chips or flakes can cause the jet engine to seize. Defective roller bearings or shafts result in loss of the aircraft.

Industrial

3. Turbine thrust bearings separate moving parts and absorb force. Industrial steam turbines may operate in series from a single source of power on the same shaft. Each turbine may have its own shaft linked, or concatenated, to the next shaft. Both methods of linking turbines use anti-friction journals, or shafts.

Elliptical bore axial groove thrust bearings are usually used in steam turbines to improve flow and drain oil to reduce heat. Groove width increases load capacity, one criteria of shaft quality. Industrial steam turbine shafts vary from low pressure to high pressure steam bearings.

Pump Shaft

4. The quality of stainless steel and nickel pump shafts is judged by straightness and size. Bearings support and guide rotating, pivoting, oscillating or sliding shafts. Bearings adhere to exact size dimensions whether the pump is for an oil well or water well. Bearing shafts are ground to a 0.001 to 0.0015-inch tolerance under the dimension of the largest diameter tolerated for a good slip fit.

Pump shafts rotate tightly. The shaft also has a surface finish. The finish allows a round smooth bar, which extends the life of the shaft. Bearings must slide over the shaft with ease and not wiggle with minimum vibration at the shaft.

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