Tag Archives: pinion cutting

Making pinions

Various texts describe pinion making as being tricky, requiring a very rigid setup to have a chance of success. The Aciera F1 is provides just such a setup. 

The first pinion I cut was for the third wheel. This is a very short pinion but I decided to only turn down one end of the O1 bar, leaving the end that was held in the collet as thick as possible to increase rigidity. Since the indexing head on the F1 only had a male centre, I left a long pivot and drilled a small hole in the end to be supported by the male centre. 


The F1 was prepared for pinion cutting by centring the indexing head on the cutter:

And aligning the male centre:

The blank was transferred to the F1 for the leaves to be cut. The full depth of 0.41mm was reached in four cuts, feeding using the leadscrew as recommended in the J Malcolm Wilde text. 

Third wheel

The third wheel is the smallest in the going train of my watch, with 90 teeth. The process for making this was:

1. Cut a wheel blank out of 0.2mm titanium sheet.

2. Attach the blank to a brass wax chuck with superglue and turn down to the wheel full diameter on the Schaublin 70 lathe.

3. Set up the Aciera F1 so that the end of the electronic indexing spindle was facing the horizontal spindle so that the 5 circles could be cut Continue reading Third wheel