Measurement of worm gears

A method of determining a minimum root radius of a worm gear member of a worm drive, said worm gear member having an axis of rotation extending in a direction Z, a periphery comprising a plurality of teeth, and a face width with said plurality of teeth being located along said face width and extending between an upper face and a lower face of said worm gear member with a tooth space having a root located between adjacent teeth, a root radius being defined between said axis and said root, said method comprising:

• probing a root of a tooth space between adjacent teeth, said probing comprising establishing a center location in said tooth space between said adjacent teeth and probing along said root at a plurality of points, each of said points being defined by a root radius position and a Z-direction position, said plurality of points forming a shape,
• best fitting a defined curve to the shape formed by said plurality of points, and determining a minimum root radius and a corresponding location in said Z-direction from said defined curve.