Warning: 0.003 inches of taper on my spindle cost me 3 days and a scrapped batch
Everybody in here keeps saying the first thing to check on a finish problem is the tool and the feeds, and I get why, but that advice burned me bad a couple weeks back. I was getting a wavy finish on the final passes of a run of 60 aluminum brackets at the plant in Fort Wayne. I tried 4 different end mills, bumped my RPMs up and down, re-ran the finish pass at half the stepover, and nothing changed. The finish still had this ripple on one side of every part. I was on it from Monday to Wednesday before a guy on nights suggested I put a dial indicator on the spindle taper and spin it by hand. Turned out the taper had about 0.003 inches of runout from a crash nobody logged months ago. That is the whole reason I am posting this. I wasted 3 days and scrapped about 12 parts chasing feeds and speeds when the machine itself was the problem. I am not saying skip the tool check, but grab an indicator and check the spindle first when the finish acts up on one side only. Has anyone else had a taper issue sneak up like that and how did you catch it before the parts started going bad?