Square nose scraper 1/2"

[Greg Carles]

Hello, new to wood turning, have classes scheduled later in September at wood craft.
I got a good deal on a Robert Sorby 1/2 inch square nose scraper , it came with an 82 degree bevel and was wondering if I should keep that grind or put a more aggressive grind such as 60-70 degree bevel. Did a search already and could not find any info on the forum about this.
I plan on using it for recessed tenons on bowl bottoms and to use on box turning on the inside of the box, and make some shoulders on various turning projects.
Thanks for any input and explaination.

 

[odie]

I keep a pretty steep angle on my scrapers, and I'd say it's somewhere around 80°, or so. A few degrees one way or the other isn't going to make much difference.

Much of the time, I manually raise my burs on a veritas tool......and, for this purpose, a steep angle has a stronger, more resilient bur, than that raised on a scraper with a lesser angle, and a more "pointy tip". I'm not sure this rule applies to a ground bur left from grinding, but it may to a lesser extent, because it's not obviously so. (You'd probably have to run a scientific test to confirm that, or not.)

All of my scrapers are ground to the same steep angle, so to make things simple for me.....never been a problem standardizing the angle, so it makes sense for me to do that.

I am also shaping tenons with a square nose scraper, and I slightly hit the right side so to make a finely ground corner. It's been so long that I did a recess, that I can't remember, but if you plan to make a dovetail, then maybe a recess would do better with a specially ground scraper. When I did do a few recesses, I did it with a square nose scraper, with the pointy side on the left.....using straight up jaws.

I do not use negative rake scrapers.....I realize they are all the rage these days, but I found that if you adjust your presentation on a standard scraper, you can essentially accomplish the same thing.

-----odie-----

 

[Dean Center]

I suspect you will start with it ground to a certain degree and change it as you get experience and develop a preference. Anything less than 90 degrees will work. The pointier, the more exciting the potential catches.

One other decision you will need to make is the angle of the left corner, as seen from the top of the tool. That also should be a little less than 90 degrees if you are going to use it on the inside of boxes. But you might want it as pointy as 75 degrees for making recesses for chucking. This too is mostly personal preference. I'd suggest starting with whatever the teacher at Woodcraft or a mentor from the local turning club suggest, and adapt as you become proficient. And opinionated.

 

[odie]

I measured last evening, and my scrapers are approximately 83°.

Note on "opinionated": This designation only applies when there is disagreement. If you follow the mainstream thought on woodturning (herd-think), it doesn't apply. A universal truth is: The one and only thing that matters is results...and results ..... "are what they are"....., and should not be confused with........

........opinions!

-----odie-----

 

[Greg Carles]

I measured last evening, and my scrapers are approximately 83°.

That sounds like my 1/2 inch square nose scraper, came in at around 82 - 83 degrees out of the box---using a protractor.

Thanks for all the information.

BTW: I visited your etsy store and WOW !!!!!!. These bowls are absolutely stunning works of art.
Do you have any videos of you turning these master pieces?

 

[odie]

That sounds like my 1/2 inch square nose scraper, came in at around 82 - 83 degrees out of the box---using a protractor.

Thanks for all the information.

BTW: I visited your etsy store and WOW !!!!!!. These bowls are absolutely stunning works of art.
Do you have any videos of you turning these master pieces?

Hi Greg, and thanks.

No, I haven't made any videos. Other turners ask me that frequently. Sorry, but it's not a high priority for me......maybe someday I might, though.

-----odie-----

 

[Dave Hulett]

I measured last evening, and my scrapers are approximately 83°.

Note on "opinionated": This designation only applies when there is disagreement. If you follow the mainstream thought on woodturning (herd-think), it doesn't apply. A universal truth is: The one and only thing that matters is results...and results ..... "are what they are"....., and should not be confused with........

........opinions!

-----odie-----

View attachment 46361

mine are ground to 79 degrees

 

[odie]

mine are ground to 79 degrees

Probably not going to make a whole lot of difference, Dave.....

Mine will change slightly, as my grinding wheel wears down.

-----odie-----

 

[robo hippy]

I have a couple of videos up about scrapers, The Big Ugly Tool, Scary Scrapers, and Shear Scraping. I don't have any that I use on bowls that are square. All are swept back to the left side. I do have some scrapers that are close to square, like maybe 80 degrees to the side of the scraper that I use when I want a square corner on the inside of a box. That particular grind would work for creating a tenon shoulder, but it would be angled slightly to the left side, while box scraper is angled to the right side. I do prefer about a 70 degree bevel on my standard scrapers, and some where between a 45/45 to a 60/30 on my NRSs. Haven't done that video yet...

robo hippy

 

[William Rogers]

I converted all mine to negative rake scrapers. Just easier to use. mine are 60/30 or 70/20 degrees. I think the included angle needs to be equal to or less than 90 degrees.

 

[Doug Freeman]

My flat scrapers are ~70°. NRS's are 30/30, so I can flip them over for inside or outside, etc, as many have an asymmetrical shape/curve. As mentioned NRS's need to be less than 90° - Stuart Batty says anywhere from 25/25 to 40/40. 30/30, with a burnished burr, just worked best for me.

As a new turner I encourage you to experiment with NRS's vs flat scrapers to see and feel the difference. My flat tops are mostly used for shear scraping, and use NRS's if the tool needs to be flat on the tool rest. Flat tops work better if hogging material out but much easier to get a catch.

 

[Greg Carles]

As a new turner I encourage you to experiment with NRS's vs flat scrapers

I appreciate the advice. I have about 4 scrapers, all non-NRS. They are a little grabby. But I am new to this hobby and don't have much experience with them yet.

 

[odie]

I do not use negative rake scrapers.....I realize they are all the rage these days, but I found that if you adjust your presentation on a standard scraper, you can essentially accomplish the same thing.

I measured last evening, and my scrapers are approximately 83°.

I've recently changed my mind about negative rake scrapers. I spent a day experimenting with scraper angles, and practicing with all three types of scrapers and burs. I want to standardize the angle, so that all standard and negative rake scrapers start with the same angle. I've changed this angle from about 83° to approximately 76°. My conclusion is the change makes manually raised burs a little easier to form. Negative rake scrapers are a little more aggressive, and require a little more sensitivity in application.

I'm now using three types of scrapers all together....

1. Standard scrapers with ground bur
2. Standard scrapers with manually raised bur
3. Negative rake scrapers

Negative rake scrapers are not the best for shear scraping, and application is mainly flat on the tool rest. Standard scrapers with a ground bur have general applications for both flat on the tool rest, and shear scraping. Manually raised burs are best suited for shear scraping only...

These are my conclusions from a day of experimenting, and I reserve the right to change my mind again.....and again.....and again!

-----odie-----

 

[robo hippy]

I agree with the 'change my mind' thing, I am always learning. A NRS with a burnished burr can do a fair job of shear scraping, but the standard scraper, with a burnished burr, works better for that. Sorby had a 'hardwood NRS' that had about an 80 degree bottom bevel, and even with a carbide rod, it was extremely difficult to burnish a burr on it. My standard scrapers are all at about 70 degrees, and burnishing a burr on them seems to work just fine. I am still searching for a perfect bevel angle formula for NRSs. I have been experimenting with a 45/45. Most of mine are 60/30, at present. With a skew chisel type, which to me is about 30/30 or even 35/35, the angle is too acute to get a burnished burr on, and that wire burr is gone way too fast.

One demo I saw that blew me away was Nick Cook, a local guy who came over from England. He was turning a hard maple lamp base in bowl grain orientation. His finish cuts were with a scraper with about a 70 degree face, and he honed and stropped the burr off. Left a very smooth surface.

robo hippy

 

[Mark Jundanian]

Currious. According to Stuart Batty the included angle of an NRS (i.e. the intersection of the top and bottom bevels) should be closer to 70*, but less than 90*. So 35/35 should work well? You might want to try 40/40 or 60/20.

 

[Doug Freeman]

Currious. According to Stuart Batty the included angle of an NRS (i.e. the intersection of the top and bottom bevels) should be closer to 70*, but less than 90*. So 35/35 should work well? You might want to try 40/40 or 60/20.

I recall in some article or something somewhere Stuart states min 50 max 70 or 80. I find 60-70 works well for me. Its balance - sharper angles wear the burr down faster, but cut a bit better, so I’ve compromised in the middle.

 

[robo hippy]

Stuart prefers the grinder burr. I prefer a burnished burr, in part because it lasts much longer. For a burnished burr, you don't have enough metal under the burr to support burnishing if you use a typical skew chisel, which is in the 30/30 range. My 60/30 seems to work fine for burnishing a burr. I do have at least one 45/45, but need more practice time with it. About the only use I have for NRSs is on boxes. Super finish with them. I did try one where I guessed the angles, but it was a Sorby 'hard wood bowl' NRS, and appeared to be about 80/20. It may work fine on some thing like hard maple, but not on softer woods.

robo hippy

 

[Doug Freeman]

you don't have enough metal under the burr to support burnishing if you use a typical skew chisel, which is in the 30/30 range

Works well for me at 30/30 or 35/35 (m2 steel). I’ll use the grinder burr, when it goes away, hone the edge and burnish with carbide. Doesnt take much force. Are you using m2 or some of your harder mat’ls? They may be too brittle for the sharper angles.

 

[robo hippy]

I use M42 and V10, D Way and Thompson. Even with very light pressure, the burr on a skew chisel doesn't hold up as well as a burr on a 60/25. I don't use them on bowls, only on boxes, and not for any roughing, finish cuts only.

robo hippy

 

[Mark Jundanian]

...and then you have Tom Wirsing's article in the Oct '22 AWT in which he recomends a 45* included angle (22.5* x 22.5*). So many ways to skin this rat.

 

[Mark Jundanian]

In the next article Cindy Drozda says she uses a 50* included angle.