Spiral markings on quill barrel

[Matanuska]

The outside of the barrel of my quill has developed spiral markings. I installed it new a few years ago as part of my PowerPro upgrade. Initially I thought they might be caused by vibration as the quill moved in and out but the markings are so uniform that now I think they may be machining marks left over from the quill fabrication. Perhaps I’m just noticing them now because the black surface treatment is starting to wear. Anybody else’s quill look like this or is something out of whack? The quill operates smoothly.

IMG_2721.jpeg (375.97 KiB) Viewed 3329 times

[thunderbirdbat]

It looks like machining marks to me. The black wears off the high spots leaving it in small indentations. The imperfections in the surface become visible along with any small scratches made by the manufacturing process. I am not sure what the final finish is sanded to but it is usually way higher than wood is finished to.

[BuckeyeDennis]

I'm going to hazard a guess that those marks are from the surface finish created by a centerless OD grinding process. Presumably using a higher axial feed rate than shown in the video below.

[edma194]

I can't imagine how that could happen while installed in your machine. It might be the finish coating is rather light or overly ground and wouldn't expose those marks normally. I had to replace a Mark 7 quill spring recently, completely remove the quill, and didn't notice any markings like that on it.

[Matanuska]

Just took a closer look at my quill and noticed the spiral doesn’t extend past the quill stop ring. It must be machining marks all have suggested that show up as the black coating wears off. Quill surface is smooth to touch so hopefully this is just cosmetic.