The RFM69HCW is an inexpensive and...
3.17 mm Supporting Axis for Rotary Tools
Each shaft is 140 mm long and will work with any 2 mm bore gears.
2x70 mm Shaft
2x130 mm Shaft
Each shaft is 60 mm long and will work with any 2 mm bore gears.
2x90 mm Shaft
2x100 mm Shaft