Results of wear tests in clean water at room temperature and at 500F are presented. The differences in result with 0.08 in. diameter and line contact riders and with much larger riders are shown. The contact stress range is from 10 psi to 9000 psi for large contact areas and from 3000 psi to over 100,000 psi for small contact areas. The majority of the testing is at a linear velocity of about 2 in. per sec. The concept of wear per unit load and per unit distance traveled for a unit wear area is used for converting sliding wear data from various test machines to a common basis for comparison. The same concept can be used for calculating from wear data the expected wear in a new design. The range and trend of friction values encountered in some of the tests is presented.Presented as an American Society of Lubrication Engineers paper at the Lubrication Conference held in Toronto, October, 1957.