Does sanding Case Harden the wood

[Faust M. Ruggiero]

I'm making some cherry turnings about 3" in diameter in the shape of a flattened tomato. Don't think pizza flattened!
I made several and one was not shaped to my liking. I decided to re-chuck it and change the shape a bit on a section that was end grain. I found it very difficult to get the spindle gouge to cut into the sanded surface. The tool was quite sharp and I know I had the cutting edge in a position it should have made a shear cut. I ended up having to lightly scrap the end grain. Does the sanding process case harden the piece?
fmr

[John Keeton]

Faust, I have never had that happen, though I suppose if one got it hot enough it could. In addition, that much heat could cause some cracks.

[Bernie Weishapl]

Faust I am not sure if that is what it is called but have had that happen a couple of time to me. I don't know if it burnishes the surface so slick that the gouge can't bite or what. I did the same as you and used a scraper then went to the gouge and it worked.

[Faust M. Ruggiero]

Thanks Bernie,
I'm trying to learn some turning skills and I've already figured out I started too late to learn enough. You may have a point about the surface being so smooth there was no place for the tool to bite. After scuffing it up with a file I was able to cut normally.
Right now I'm consuming scrap pieces trying to learn to make beads with a skew. It's a good thing I can laugh at myself. Here I am with this brand new lathe and a bunch of first class tools making beads that look like a beaver chewed them. I made so many "skates" I'm feeling like Hans Christian Anderson. I'm also having a lot of fun trying.
fmr

[Wally Dickerman]

It seems to me that if the surface has been "case hardened", then you are pressing too hard when you sand, and possibly at too much speed. Sanding should be done with a fairly light touch. Heat is your enemy. Also, don't over use the sandpaper. Throw away used sp. As the saying goes..use sandpaper like someone else is paying for it.

Actually, I suggest that you try it. Hold a piece of well used sandpaper, using firm pressure, against a piece of spinning wood. You'll find that it burnishes or "case hardens" quite easily.

Wally

[Faust M. Ruggiero]

Hey Wally,
I tried what you said. Worn paper heated up very quickly. That must be what happened. My ability to get the shape I wanted with a spindle gouge left something to be desired. I had to sand quite a bit. Since I am sure it will be a while until I learn tool control well enough to create shapes that need sanding only to finalize the finish and not to finalize the shaping, I will have to be more careful about sanding. Thanks for the education.
fmr

[Steve Schlumpf]

Faust - one other thing to take into consideration is that end-grain is a lot harder to sand or cut than face-grain. When sanding, in addition to fresh sandpaper and light pressure, make sure that your lathe speed is fairly slow and it will help from generating to much heat.