Established in 1952

Page: 2190

Basic Magnetically-Mounted Authenticator
AUT-2000

			An Authenticator™ is a device used to evaluate the axis of rotation of a precision spindle. It is basically a coupling device. It holds an Ultra Precise Test Sphere and temporarily, but rigidly attaches it to the spindle being evaluated. The very basic magnetic Authenticator™ (our Part Number AUT-2000) uses a powerful rare earth magnet with a holding power in excess of 60 pounds (27.2 KG) to attach the Ultra Precise Test Sphere to the spindle. The flat surface of this magnet is simply placed against a magnetically permeable flat face plate that is perpendicular to the spindle axis. It is placed with the sphere approximately centered with the spindle axis. A soft head hammer is used to tap the outside rim until the sphere is in the desired location in relation to the spindle axis.
	Magnetically Mounted Spindle Authenticator

Because the holding power of the large rare earth magnet is so great, we provide a jack screw on each side of the device to break the magnetic pull, so that it can be easily removed from the spindle at the end of the test. This same set of jack screws can be used to reduce the magnetic pull when first placing the magnet on the spindle. By advancing one or both of the jack screws a slight amount, the Ultra Precise Test Sphere can be easily tapped into approximate position. Then the full power of the magnet is applied by withdrawing the jack screws, thus allowing the magnet to come into full contact with the spindle face.

The one inch (25.4 mm) diameter Ultra Precise Test Sphere is produced from very fine grained high chrome high carbon stainless steel. It is hardened to 58 Rockwell C for wear-resistance and ultra-cold cycled for long term dimensional stability.

The Ultra Precise Test Sphere is just that, it is spherical within 2.5 micro inches (63.5 nm) maximum and has a surface finish that is better than 0.5 micro inches (12.7 nm) Ra. This is ten times more accurate than high quality bearing balls. Spheres of this quality are simply not commercially available.

Unlike tungsten carbide, this material has good uniform electrical conductivity which is so important for spindle bearing evaluation when using non contact capacitance gage.

The body of the Basic Magnetic Authenticator is machined from a single piece of 2-3 /4 inch (69.85 mm) diameter very highly permeable magnetic material. This body is electro less nickel plated for corrosion resistance.

Each Authenticator has an individual identification number permanently marked on its body. An individual polar chart recording documenting the roundness of the Ultra Precise Test Sphere is supplied with each Authenticator™. The Ultra Precise Test Sphere is attached to the body of the Authenticator™ in a manner that provides an ultra low electrical resistance between it and the body. This is extremely important when using capacitance gages for the critical evaluation of the spindle characteristics.

The Ultra Precise Sphere is not just glued to the body. A steel pin extends deep into a hole in the sphere and into the body to achieve an extremely strong connection.

In order to preserve the dynamic balance of the device, all details are maintained very symmetrical, dimensionally balanced and constant.

Authenticator Page