The BAUER 4-tooth claw system found in P7 and P8 series 16mm projectors is as follows:

The claw tooth spacing AB (Fig. 1) is smaller, while the spacing BC and CD are larger than the standardized spacing of the perforation holes.

When running forwards and with perfect perforation, only the claw tooth B is in contact with the edge of the perforation hole b (black arrow). It transports the film by the cut length S (Fig. 2).

If the perforation hole b is damaged, the transport is carried out by the tooth C (Fig. 3), the other teeth do not touch the film (light arrows).

If hole c is damaged, tooth D transports (Fig. 4) and if hole d is also damaged, tooth A transports.

The same applies to reverse motion, except that tooth C is the working tooth and the sequence of the receiving teeth is C, B, A and D.