Motor Shaft Adapter Coupler 15mm 16mm 17mm 18mm 19mm 20mm 22mm 24mm 25mm 28mm 30mm 35mm Single Disk Coupling Od 68mm - Shaft Couplings - AliExpress
SPROCKET ADAPTER – Saltbmx
Motor Shaft Collet Chuck Extension Rod Holder ER11A 5mm Mini CNC Milling Spindle Toolholder For Boring Tapping Grinding From Shuzhanonline, $8.97 | DHgate.Com
Bike Trainer thru Axle Adapter - The Robert Axle Project
HEX axle tool; Multifunctional 17-19-22-24 mm - Eastbound
8mm to 11mm Stepper Motor Shaft Sleeve 8x11mm Bore Adapter Turbine Reducer Shaft Sleeve for RV030 Worm Gear Speed Reduce RV30 Gearbox 0.31inch: Amazon.com: Industrial & Scientific