While playing Assetto Corsa i was not satisfied with the lengt of the shifting lever. For driving old cars like Group C or early 90s F1 the shifter felt way too long so i designed a shorter knob that pertrudes only about 1.5 cm above the rod (about 2 cm less than the default knob).

The bore is 9.18 mm diameter for the most part, for the threaded part on the top its stepped down to 8.2 mm to grip the threads.

With my printer it was a friction fit but my tolerances are pretty bad so your mileage might vary.