Okay all, so I have one of the Sieg 7X14 Mini lathes and it seems that the spindle has about 4 6 thousandths of play. This measured from both the top of the main housing, and the bed ways both. Now my dial indicator is not an expensive one, but it does seem consistent. So I'm turning the breech end of a .257 barrel for my Condor and notice that even though I get it within .002 run out it was cutting oblong rather than correctly circular. So I take the jaws out of the chuck, clean them, and the chuck, then reassemble. Check it before the cleaning and it's 12 thousandths with an aluminum rod. Aftr the cleaning check it again this time using an 1/8 inch drill bit, same result 12 thousandths. So any good ideas? I already tried using an extra fine round shone on the chucks jaws just lightly and when I chucked the barrel up it was almost dead on. Maybe the tool post doesn't have enough rigidity? Going to tear the head stock down this weekend and upgrade the berrings to tapered roller ones and see if that takes a bit more of the play/run out up. Guess I'll order a steel tool post and new holders and adjust the cross slide jibs again just to be sure those are as close as I can get them. I hate having to chop off another 3 inches of barrel to redo that Air Force breech diameter without it ending up oval again. Guess I'll test it with a small piece of aluminum or steel rod and see if it stays circular.Any and all ideas, input pointers or suggestions are welcome. I value everyones advice here, you have all guided me in the right direction over the years.Thanks in advance,CaseyOh if you happen to read this Mr. Noble, PM me about one of your great 257 valves please.
Ed, did your runout cause an oblong piece? I’m just having a hard time seeing how oblong can happen, maybe I’m missing something.Casey, by the time you get this figured out and corrected, you’ll know that machine intimately, which will make you way better at making it do what you want. There may be a Sieg forum somewhere, maybe at groups.io, where you can go from our generic pontificating to people who know that specific machine and it’s peculiarities.