I really need to redo my scraper video....
So, uphill/down hill: When roughing it doesn't really make much difference because the important part is removing bulk as efficiently as possible, and getting to the final shape. For finish cuts, yes, you get way better surfaces if you are cutting down hill. With shear scraping, it is a bit different as the cuts are so fine you can generally go in either direction and get the same surface.
You can use scrapers on spindle work. Mike is doing a scraping cut, which does leave an okay surface. His 50 degree angle is a bit on the pointy/acute side to me. If you use a scraper for a peeling cut, you get a much better surface. I wouldn't try a peeling cut with a 50 degree scraper, though a 70 or 80 degree scraper works pretty well, and leaves a nice surface, sandable at about 150 to 220 grit. A better surface is achieved if you use a skew for the peeling cuts which leave me with a 220 or so surface ( yes, this will be another video). Where this type of cut comes in really handy is for us mere mortal skew users who are not up to Richard Raffen and Al Lacer levels. Especially if we are making wavy type shapes, we get tool marks which are a pain to sand out. If you use a blunt scraper or skew for a peeling cut, you can remove all of the tool marks and have a surface that is much less like a washboard.
Shear scraping with a round nose scraper: I recently posted a video about shear scraping, almost 2 months ago. If I am shear scraping with a round nose scraper, ALWAYS have the handle down, not up/elevated. Yes, standard way to use a scraper, for a scraping cut is to lift the handle. When doing shear scraping, since you are not doing a scraping cut, this is not a safety issue. If you raise the handle when you do a shear scrape, it becomes a safety issue. The reason for this, as I explain in my video is that with the handle raised you can get on the high side of the round nose, and you get the same catch that you do if you are on the high side of a skew chisel. The tool is unbalanced. By keeping the handle low, you can not get on that high side, so there is no catch risk.
The best cutting edge for a shear scraper is a burnished burr. I do need to send Mike a few burnishing rods... That burnished burr is also excellent on the 80/25 degree NRS for both bowls and spindles, and yes, they actually use it as a peeling cut on bowls (Sorby hard wood NRS tool video). Freaky, but it does work really well.
The cheater bar that Ernie uses: You may need one on a long bed lathe. If you have a sliding headstock, and have it all the way down on the end, you just set your tool rest to 90 degrees to the bed and you don't need a cheater bar/extended secondary lever.
robo hippy