Centering Tubing on a Lathe

摘要

Centering glass tubing to rotate straight on a lathe can be a big problem, especially when there is substantial warpage in the tubing. The following adaptation to a universal chuck's donut can simplify the matter to a great extent. The original donut that I had with my lathe chuck was 64 mm in diameter. When I later purchased some finned donuts. I noticed they were larger in diameter (75 mm) and at first I thought I would have no use for the old ones. Unfortunately, glass tubing was not held adequately straight by the single set of finned donuts, so in an attempt to provide some balanced support, I taped (using masking tape) some heavy Kevlar woven tape to the smaller (older) donuts to make up for the diameter difference. What I had not expected was that the ends of the Kevlar tape tend to bunch-up against the masking tape resulting in a wider diameter at these regions (see Figure 2).