蝸桿軸，導螺桿

I was a little worried about getting the right part, but this worm shaft threaded into place on my bench lathe without any drama. The threads are clean and it feels solidly machined, definitely solved my vibration issue.

The fit on my SC4 was spot-on, no grinding or slop during the first few test passes. The threads engage smoothly and it's held up fine through a couple of hours of light threading work.

I was worried about compatibility with my SC4, but this worm shaft dropped right in with no modifications needed. The threads are cut cleanly and the steel feels solid compared to the original part that wore out.