This is a 3D model of an IBM/Simplex secondary clock delay sector gear with 66 teeth. This copper-plated steel delay sector works in conjunction with a correction solenoid to initiate hourly and daily time correction cycles in a Hansen movement, used in IBM/Simplex synchronized clock systems. The part of this sector that first comes into contact with the steel minute pickup ratchet of the Hansen movement often experiences the most wear. Since new replacement delay sectors are difficult to find and no longer seem to be produced, I decided to create a replacement.

This piece is supposed to be manufactured on a CNC machine or using electrical discharge machining, not 3D printed.

To reduce potential future wear of the pickup ratchet, I decided to manufacture this part from brass, as it has better self-lubricating properties. Additionally, I can easily re-manufacture and replace the sector if needed. This brass sector shown in the photos was produced by PCBWay using wire-cut electrical discharge machining (EDM). While EDM resulted in slightly less smooth teeth finish compared to CNC machining, it is a far more economical method for achieving this level of precision.

For more information on IBM/Simplex secondary clock check my website.