Gear 2.2

2.2 Klingelnberg Palloid method
One development， which did not fall into line with the Gleason and Oerlikon methods， was patented by the engineers Schlicht and Preis in the 1920's. This invention was based on a bevel- worm shaped miller （similar to the spur and helical gear hobber) and created a nearly uniform tooth depth along the face width. The miller shown in Figure 3 swivels tangentially on its axis onto a selectable base circle， and rotates around the plane gear axis during milling. Work begins on the large diameter， and generates an involute tooth trace. The angle of spiral is determined through the selection of the base circle. Because of the tiny slots available for the miller to pass on the small diameter， only very small chip removal magnitudes are achieved.
Figure 3： Method using bevel-worm-shaped milling tool （Klingelnberg-Palloid)
（Source， Klingelnberg Sons)
Klingelnberg adopted this method and built the first machine for the so-called Palloid Method in 1923. Figure 4 shows a full view of the Klingelnberg machine， which also， interestngly enough， shows that construction of the machine is “mirror-backward” as compared with bevel gear machines in use both then and now.
Advantages， which even today occasionally lead to the application of the Palloid method，are to be found in the involute tooth trace （insensibility to displacement) the flaky enveloping lines （smooth rolling and oil-pocket effect) and in the fully rounded root region
（no grooving effect). The low sensitivity to gearbox and shaft distortions and high break-point capabilities predestine this method for use in racing and touring vehicles.
Figure 4： Klingelnberg gear machine for bevel shaped milling tool，1923
{Source， Klingelnberg Sons)。