It has been brought to my attention that some of the 3mm rods are too tight in the J5 housing and the bearings. I went through my supplies and found the last batch of rods measured 3.04mm and the newest batch measured 2.98mm. Please measure your rods and do not force them onto the bearings if you have rods larger than 2.98mm. I would not use these unless you can chuck them up and evenly polish them down to 2.98mm. If you are experiencing this problem please contact me so we can figure out the best way to get your rods corrected.