Abstract: A ball nose end mill comprises a body having a semi-spherical front surface and a plurality of indexable cutting inserts. A central one of the inserts is of generally triangular shape, and the additional inserts are of generally rectangular shape. The central insert has a generally convexly curved top surface, and the cutting edges thereof include main cutting edges which are convexly curved when the central insert is viewed from the side.

Abstract: For determining the relative humidity of a highly moist gas, particularly air exiting from a wood-drying apparatus, there is used a humidity sensing arrangement having a capacitive sensor, whose capacitance varies with changes in the relative humidity of gas to which it is exposed, and means for generating an output signal proportional to the prevailing capacitance of said capacitive sensor. The capacitive sensor is exposed to a heated partial flow of the highly moist gas, and the output signal of the output signal generating means is modified in correspondence with the extent to which the partial flow has been heated.