I use the Eflite EFLM1925L collet adapter. It fits a 5mm motor shaft, has a 1/4-28 threaded shaft with a bullet nut and has a 3/8” short extension to catch the precision alignment surface of APC props. I ream out the non-precision 1/4 inch hole in the APC prop to clear and let the precision 3/8 inch hole guide the prop onto the collet adapter. The Eflite adapter is available at Horizon Hobby, Amazon or your LHS.
Pete