Hi Annin. This is VUCAtech in Korea. I got my items delivered last month. I have two question. (AR 4) Q1 : J4 turret housing and needle roller bearing assemblying is very loos. Please check Pic 1. Is this correct? Q2 : J4 main shaft ' OD is 25.4mm and needle roller bearing's ID is 24.5mm. The two cannot be assembled. In addition, the needle roller bearing OD is 30.25mm. Different from B1616 (1x1-1/4x1 inch) needle roller bearing OD dimensions. (Pic 2, Pic 3). Please check the needle roller bearing we received. I look forward to your quick reply. Thank you.