"Owen Lowe" wrote in message
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Would the bevel angle on the underside of a scraper affect the surface
quality achieved? The bevel acts as support for the edge as well as
establishing the clearance angle behind(under) the edge. In other words,
would it make any difference to the surface finish scraping with an edge
formed by an 85 degree angle vs. a 60 degree angle?

Remaining in this line of thought, consider a bench plane and the mouth
opening for the iron. The front of the mouth supports the wood and helps
keep the cut from becoming a tear in the grain and running ahead of the
iron's edge. I wonder if some sort of scraper design could be devised
such that there's a hood just above the scraper edge that might serve
the same purpose. (Something along the lines of the Proforme or other
shielded hollowing cutters.)


Edge is an edge. For the type of scraping we do, the bevel is just a
sharpening phenomenon. Some scrapers are ground at 90 degrees to the face
and still scrape when turned on edge. I'm a clean edge scraper fan, but
some leave the wire edge from sharpening on the tool, and old Frank Pain
turned his carbon steel with a burnisher. Means their edge is entirely
independent of the bevel.

As far as devising a turning plane, I think you need to remember that
rotation is changing our stock presentation to us even as we bring the tool
to it. Try to figure the optimum type of shaving from one presentation, and
it changes with the curve and rotation. For instance, I prefer to shear the
outsides of my turnings, producing full twisted shavings , but there is a
certain point on the curvature where I take almost no shear, to avoid
picking out tiny pieces of side grain. Those who have turned ring porous
wood will recognize that effect. For inside you'd need a double curve,
(like a gouge?) to have a chance to get a stable shaving, which of course
would only be of one type based on exposure, clearance, and bevel angle, and
would be entirely unsuitable in some grain orientations.

Though I have used planes on the outside of spindle turnings to good effect,
I think the best thing you can do for your surface is to take the thinnest
shaving possible. Won't be perfectly suited to all circumstances, but it'll
give the best overall results. If you're forced to scrape, so be it. Also
take the thinnest as best compromise.

Here's one scraper I use all the time
http://www.leevalley.com/wood/page.a...at=1,310,41069 to
scrape the button at the bottom, and the last of a tenon, when I use one.
Also the bowls of spoons.