First of all, there is enough space in the blank. If the bar is directly clamped on the machine, if the inner diameter of the pipe is hardwood or PTFE rod, or other plastic rod, or even iron rod, just tighten the pipe and start turning, and grind the stainless steel rod with a knife of 2-3 mm thickness. There are many in this general hardware store. If the black reinforced PTFE is hard, turn it with a tungsten steel blade. When turning, you don't need to spray water, just blow dry the car directly. Note that it expands with heat and contracts with cold.

In some cases, the manufacturer's specifications do not meet the blank specifications required by customers, so they will adopt the plastic method, heat it, put it on iron bars or drums, make the small sleeve bigger, or make the big sleeve smaller. In this way, it will be hot when you process the car, and the products will return to the original similar specifications. So the outer diameter * inner diameter * thickness you originally prepared is 100*800*20, or it may be 99*79*20 or 10 1*8 1*20.