Since I bought it for the first time, I didn't know how to use it at first. I didn't know there was a correct position for the collet to fit in, so the drill bit didn't go straight and I doubted accuracy. However, if the collet was put in the correct position before the nut was attached (there should be a clicking sound and the tip should be flat), it was reasonably accurate. For DIY level work, there is no problem even if there is a slight deviation from the core compared to high precision products.
Thanks!