Experiments were carried out on roughness models of planed and turned surfaces made of metal measured by, means of a computer assisted profilographometre designed by the author. Measurements were performed using three gauging tips with the following angles: a = 60° 75° and 90°, The rounding radius of tips was r = 100 gm (Fig. ), R_a and R_m roughness parameters were determined, in accordance with the PN-84/D-01005 standard were. determined. Results of investigations are presented in the table.

Analysing measurement results from the above table it can be observed that, as expected. the larger the angle of the gauging tip, the lower the roughness parameter values. This can be attributed to the impossibility of representation of surface indentations at large edge angles. However, this influence is only slight because of a large flare angle of the profile of the surface roughness.