12-22-2019, 01:16 PM
I only watched about a minute, but could tell he was on target. It demonstrates exactly what I was talking about.
BTW, it doesn't just happen with small dia material. While in the Navy I'd stub twisted pump shafts to put them back in service. They were about 3 1/2" in diameter in the middle and roughly 3ft long. One had to dial in the diameter in the chuck and the end hanging out in the middle of the air. We then would use a steady rest to keep it aligned while making the repairs. Same was true when we would simply repair the bearing diameters by welding or electro plating. The bearing diameters were about 18 or 20 inches apart and had to have no more than .001" TIR. More than that put the bearings in too much strain due to misalignment.
BTW, it doesn't just happen with small dia material. While in the Navy I'd stub twisted pump shafts to put them back in service. They were about 3 1/2" in diameter in the middle and roughly 3ft long. One had to dial in the diameter in the chuck and the end hanging out in the middle of the air. We then would use a steady rest to keep it aligned while making the repairs. Same was true when we would simply repair the bearing diameters by welding or electro plating. The bearing diameters were about 18 or 20 inches apart and had to have no more than .001" TIR. More than that put the bearings in too much strain due to misalignment.