To Negative Rake or not to Negative Rake. That is the question.

[doragus]

I'm still not overly confident with gouges so I use carbide tools a lot and scrapers a fair bit. There is a lot of material around on the benefits of negative rake scrapers but so many opinions on the actual bevel angles. My questions are, is it worth changing some of my scrapers to negative rake and, if so, what are the suggestions for bevel angles?
Thanks
Chris

[Paul39]

Your normal scraper tilted down 10 - 15 degrees is negative rake scraper. A skew run straight in is a negative rake scraper. The only advantage I can see with buying or making a NRS is if you have no room to tilt a scraper down, as in boxes or tall thin vases.

As I make mostly good sized bowls, I have not felt the need form a NRS. Recently in a weak moment I did buy a used NRS at a good price. After a quick trial I can see no advantage over a regular scraper tilted down to whatever angle shaves off tissue paper thin shavings. There are many discussions about having a burr or not having a burr, and how to achieve same. Do a search here and on Google about NRS. Also look up Robo Hippy YouTube videos about using scrapers.

There are so many variables in turning that one can not say that any tool, ground at any specific angle, will give a clean cut on any specific timber, with any specific moisture content, on any given day or phase of the moon.

There is more art than science to turning. What worked for me is using one tool, sharpened the same way, on many blanks of the same kind of timber. After about 10 or 15 hours over a week or so it became instinctive on just how to present the freshly sharpened tool to make a nice clean cut. Once the feel of the cutting is learned, the tool will tell you when to sharpen. When we learn on one kind of timber, anything stuck on the lathe can be turned by feel and instinct.

Some days nothing will work but starting with 80 grit sandpaper and working in steps to 220 grit.

[NeilS]

Your normal scraper tilted down 10 - 15 degrees is a negative rake scraper. A skew run straight in is a negative rake scraper.



Agreed.

IME, the angles are not so critical, but forming and keeping a keen edge (with or without a burr) is.

I found the most helpful tool when learning to prepare a scraper edge is a 30x loupe (https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=loupe+30x&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=loupe).

Try any angle (like your current skew angles) and see how you go.

And, as always....

[NeilS]

Some days nothing will work but starting with 80 grit sandpaper and working in steps to 220 grit.



What, no #40 or #60, Paul?.....:U

[turnerted]

I have a couple of double sided negative rake scrapers which I use frequently .When I am using them, I leave the grinder running so's I can keep touching them up .One big advantage of a scraper like this, is that I think it is almost imposible to get a catch .
Ted

[doragus]

Thanks guys. I'm going to give them a go. Think I might need a sharpener upgrade though.
Chris