I have been trying to figure out the dials on my south bend 9b that I rebuilt last year. I tried measuring cuts once before and it seemed that everything was double, 5 on the dial took 10 thou off; 10 took 20 thou off. Not sure if that is how it was designed, but now I am not sure that is even correct.
Just now, I chucked up a piece of scrap rifle barrel I had to mess around with threading the muzzle.
Initial measurement was .595" so figured I'd take it down to an even .5
Now assuming that the dial measures in thousandths, I did the following
First cut was 10 thou, then a second cut at 5 thou, and a third again at 5 thou. Total of 20 thou, with the dial on 20. Measurement after those cuts was .572, which not exact, but not terrible for the old lathe.
After that I set set the dial at 30 for another 10 thou cut. This time it took roughly 30 thou total off(did not rezero) measuring .538". Not good at all. Rezeroed the dial, turned it to 10 thou, measured it an this time it took 38-40 thou off. measuring right about .5". So while I did reach my desired diameter, it was by pure luck.
Anyone have any thoughts on what could be going on? I thought about setting up a DRO on it, but not sure if it would be worth the money vs just buying a newer lathe
Just now, I chucked up a piece of scrap rifle barrel I had to mess around with threading the muzzle.
Initial measurement was .595" so figured I'd take it down to an even .5
Now assuming that the dial measures in thousandths, I did the following
First cut was 10 thou, then a second cut at 5 thou, and a third again at 5 thou. Total of 20 thou, with the dial on 20. Measurement after those cuts was .572, which not exact, but not terrible for the old lathe.
After that I set set the dial at 30 for another 10 thou cut. This time it took roughly 30 thou total off(did not rezero) measuring .538". Not good at all. Rezeroed the dial, turned it to 10 thou, measured it an this time it took 38-40 thou off. measuring right about .5". So while I did reach my desired diameter, it was by pure luck.
Anyone have any thoughts on what could be going on? I thought about setting up a DRO on it, but not sure if it would be worth the money vs just buying a newer lathe